Connections between cells which allow passage of small molecules and electric current. Gap junctions were first described anatomically as regions of close apposition between cells with a narrow (1-2 nm) gap between cell membranes. The variety in the properties of gap junctions is reflected in the number of CONNEXINS, the family of proteins which form the junctions.
A group of homologous proteins which form the intermembrane channels of GAP JUNCTIONS. The connexins are the products of an identified gene family which has both highly conserved and highly divergent regions. The variety contributes to the wide range of functional properties of gap junctions.
A 43-kDa peptide which is a member of the connexin family of gap junction proteins. Connexin 43 is a product of a gene in the alpha class of connexin genes (the alpha-1 gene). It was first isolated from mammalian heart, but is widespread in the body including the brain.
Direct contact of a cell with a neighboring cell. Most such junctions are too small to be resolved by light microscopy, but they can be visualized by conventional or freeze-fracture electron microscopy, both of which show that the interacting CELL MEMBRANE and often the underlying CYTOPLASM and the intervening EXTRACELLULAR SPACE are highly specialized in these regions. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p792)
Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)
An agent derived from licorice root. It is used for the treatment of digestive tract ulcers, especially in the stomach. Antidiuretic side effects are frequent, but otherwise the drug is low in toxicity.
Specialized junctions between NEURONS which connect the cytoplasm of one neuron to another allowing direct passage of an ion current.
The attachment of PLATELETS to one another. This clumping together can be induced by a number of agents (e.g., THROMBIN; COLLAGEN) and is part of the mechanism leading to the formation of a THROMBUS.
Non-nucleated disk-shaped cells formed in the megakaryocyte and found in the blood of all mammals. They are mainly involved in blood coagulation.
Blood clot formation in any part of the CAROTID ARTERIES. This may produce CAROTID STENOSIS or occlusion of the vessel, leading to TRANSIENT ISCHEMIC ATTACK; CEREBRAL INFARCTION; or AMAUROSIS FUGAX.
Formation and development of a thrombus or blood clot in the blood vessel.
An enzyme formed from PROTHROMBIN that converts FIBRINOGEN to FIBRIN.
The process whereby PLATELETS adhere to something other than platelets, e.g., COLLAGEN; BASEMENT MEMBRANE; MICROFIBRILS; or other "foreign" surfaces.
The number of PLATELETS per unit volume in a sample of venous BLOOD.
Cell-cell junctions that seal adjacent epithelial cells together, preventing the passage of most dissolved molecules from one side of the epithelial sheet to the other. (Alberts et al., Molecular Biology of the Cell, 2nd ed, p22)
Any of several ways in which living cells of an organism communicate with one another, whether by direct contact between cells or by means of chemical signals carried by neurotransmitter substances, hormones, and cyclic AMP.
Family of the suborder HAPLORHINI (Anthropoidea) comprising bipedal primate MAMMALS. It includes modern man (HOMO SAPIENS) and the great apes: gorillas (GORILLA GORILLA), chimpanzees (PAN PANISCUS and PAN TROGLODYTES), and orangutans (PONGO PYGMAEUS).
An oleanolic acid from GLYCYRRHIZA that has some antiallergic, antibacterial, and antiviral properties. It is used topically for allergic or infectious skin inflammation and orally for its aldosterone effects in electrolyte regulation.
A colorless liquid with a fragrant odor. It is used as an intermediate, solvent and in cosmetics.
Neurons of the innermost layer of the retina, the internal plexiform layer. They are of variable sizes and shapes, and their axons project via the OPTIC NERVE to the brain. A small subset of these cells act as photoreceptors with projections to the SUPRACHIASMATIC NUCLEUS, the center for regulating CIRCADIAN RHYTHM.
The 2nd cranial nerve which conveys visual information from the RETINA to the brain. The nerve carries the axons of the RETINAL GANGLION CELLS which sort at the OPTIC CHIASM and continue via the OPTIC TRACTS to the brain. The largest projection is to the lateral geniculate nuclei; other targets include the SUPERIOR COLLICULI and the SUPRACHIASMATIC NUCLEI. Though known as the second cranial nerve, it is considered part of the CENTRAL NERVOUS SYSTEM.
The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.
A phosphoinositide present in all eukaryotic cells, particularly in the plasma membrane. It is the major substrate for receptor-stimulated phosphoinositidase C, with the consequent formation of inositol 1,4,5-triphosphate and diacylglycerol, and probably also for receptor-stimulated inositol phospholipid 3-kinase. (Kendrew, The Encyclopedia of Molecular Biology, 1994)
GTP-BINDING PROTEINS that contain three non-identical subunits. They are found associated with members of the seven transmembrane domain superfamily of G-PROTEIN-COUPLED RECEPTORS. Upon activation the GTP-BINDING PROTEIN ALPHA SUBUNIT of the complex dissociates leaving a dimer of a GTP-BINDING PROTEIN BETA SUBUNIT bound to a GTP-BINDING PROTEIN GAMMA SUBUNIT.
Regulatory proteins that act as molecular switches. They control a wide range of biological processes including: receptor signaling, intracellular signal transduction pathways, and protein synthesis. Their activity is regulated by factors that control their ability to bind to and hydrolyze GTP to GDP. EC 3.6.1.-.
A subclass of phospholipases that hydrolyze the phosphoester bond found in the third position of GLYCEROPHOSPHOLIPIDS. Although the singular term phospholipase C specifically refers to an enzyme that catalyzes the hydrolysis of PHOSPHATIDYLCHOLINE (EC 3.1.4.3), it is commonly used in the literature to refer to broad variety of enzymes that specifically catalyze the hydrolysis of PHOSPHATIDYLINOSITOLS.
The exchange or transmission of ideas, attitudes, or beliefs between individuals or groups.
The teaching staff and members of the administrative staff having academic rank in a medical school.
A province of eastern Canada. Its capital is Quebec. The region belonged to France from 1627 to 1763 when it was lost to the British. The name is from the Algonquian quilibek meaning the place where waters narrow, referring to the gradually narrowing channel of the St. Lawrence or to the narrows of the river at Cape Diamond. (From Webster's New Geographical Dictionary, 1988, p993 & Room, Brewer's Dictionary of Names, 1992, p440)
Cells of epithelial origin possessing specialized sensory functions. They include cells that are found in the TASTE BUDS; OLFACTORY MUCOSA; COCHLEA; and NEUROEPITHELIAL BODIES.
Bulbous enlargement of the growing tip of nerve axons and dendrites. They are crucial to neuronal development because of their pathfinding ability and their role in synaptogenesis.
Locomotor behavior not involving a steering reaction, but in which there may be a turning random in direction. It includes orthokinesis, the rate of movement and klinokinesis, the amount of turning, which are related to the intensity of stimulation.
A genus of mosquitoes (CULICIDAE) frequently found in tropical and subtropical regions. YELLOW FEVER and DENGUE are two of the diseases that can be transmitted by species of this genus.
One of the BIOLOGICAL SCIENCE DISCIPLINES concerned with the origin, structure, development, growth, function, genetics, and reproduction of animals, plants, and microorganisms.
Slender tubular or hairlike excretory structures found in insects. They emerge from the alimentary canal between the mesenteron (midgut) and the proctodeum (hindgut).
Proteins that take part in the formation or structure of TIGHT JUNCTIONS.
Small double-stranded, non-protein coding RNAs (21-31 nucleotides) involved in GENE SILENCING functions, especially RNA INTERFERENCE (RNAi). Endogenously, siRNAs are generated from dsRNAs (RNA, DOUBLE-STRANDED) by the same ribonuclease, Dicer, that generates miRNAs (MICRORNAS). The perfect match of the siRNAs' antisense strand to their target RNAs mediates RNAi by siRNA-guided RNA cleavage. siRNAs fall into different classes including trans-acting siRNA (tasiRNA), repeat-associated RNA (rasiRNA), small-scan RNA (scnRNA), and Piwi protein-interacting RNA (piRNA) and have different specific gene silencing functions.
A gene silencing phenomenon whereby specific dsRNAs (RNA, DOUBLE-STRANDED) trigger the degradation of homologous mRNA (RNA, MESSENGER). The specific dsRNAs are processed into SMALL INTERFERING RNA (siRNA) which serves as a guide for cleavage of the homologous mRNA in the RNA-INDUCED SILENCING COMPLEX. DNA METHYLATION may also be triggered during this process.
The result of a positive or negative response (to drugs, for example) in one cell being passed onto other cells via the GAP JUNCTIONS or the intracellular milieu.

The bystander effect in the HSVtk/ganciclovir system and its relationship to gap junctional communication. (1/2680)

The bystander effect (BSE) is an interesting and important property of the herpes thymidine kinase/ganciclovir (hTK/GCV) system of gene therapy for cancer. With the BSE, not only are the hTK expressing cells killed upon ganciclovir (GCV) exposure but also neighboring wild-type tumor cells. On testing a large number of tumor cell lines in vitro, a wide range of sensitivity to bystander killing was found. Since transfer of toxic GCV metabolites from hTK-modified to wild-type tumor cells via gap junctions (GJ) seemed to be a likely mechanism of the BSE, we tested GJ function in these various tumors with a dye transfer technique and pharmacological agents known to affect GJ communication. We confirmed that mixtures of tumor cell resistant to the BSE did not show dye transfer from cell to cell while bystander-sensitive tumor cells did. Dieldrin, a drug known to decrease GJ communication, diminished dye transfer and also inhibited the BSE. Forskolin, an upregulator of cAMP did increase GJ, but directly inhibited hTK and therefore its effect on BSE could not be determined. We conclude that these observations further support port the concept that functional GJ play an important role in the BSE and further suggest that pharmacological manipulation of GJ may influence the outcome of cancer therapy with hTK/GCV.  (+info)

Three-dimensional structure of a recombinant gap junction membrane channel. (2/2680)

Gap junction membrane channels mediate electrical and metabolic coupling between adjacent cells. The structure of a recombinant cardiac gap junction channel was determined by electron crystallography at resolutions of 7.5 angstroms in the membrane plane and 21 angstroms in the vertical direction. The dodecameric channel was formed by the end-to-end docking of two hexamers, each of which displayed 24 rods of density in the membrane interior, which is consistent with an alpha-helical conformation for the four transmembrane domains of each connexin subunit. The transmembrane alpha-helical rods contrasted with the double-layered appearance of the extracellular domains. Although not indicative for a particular type of secondary structure, the protein density that formed the extracellular vestibule provided a tight seal to exclude the exchange of substances with the extracellular milieu.  (+info)

Morphogenesis of the Caenorhabditis elegans male tail tip. (3/2680)

Using electron microscopy and immunofluorescent labeling of adherens junctions, we have reconstructed the changes in cell architecture and intercellular associations that occur during morphogenesis of the nematode male tail tip. During late postembryonic development, the Caenorhabditis elegans male tail is reshaped to form a copulatory structure. The most posterior hypodermal cells in the tail define a specialized, sexually dimorphic compartment in which cells fuse and retract in the male, changing their shape from a tapered cone to a blunt dome. Developmental profiles using electron microscopy and immunofluorescent staining suggest that cell fusions are initiated at or adjacent to adherens junctions. Anterior portions of the tail tip cells show the first evidence of retractions and fusions, consistent with our hypothesis that an anterior event triggers these morphogenetic events. Available mutations that interfere with morphogenesis implicate particular regulatory pathways and suggest loci at which evolutionary changes could have produced morphological diversity.  (+info)

Gap junction signalling mediated through connexin-43 is required for chick limb development. (4/2680)

During chick limb development the gap junction protein Connexin-43 (Cx43) is expressed in discrete spatially restricted domains in the apical ectodermal ridge (AER) and mesenchyme of the zone of polarising activity. Antisense oligonucleotides (ODNs) were used to investigate the role of Connexin-43 (Cx43) in the development of the chick limb bud. We have used unmodified ODNs in Pluronic F-127 gel, which is liquid at low temperature but sets at room temperature and so remains situated at the point of application. As a mild surfactant, the gel increases antisense ODN penetration and supplies ODNs to the embryo continually for 12-18 h. We have shown a strong decrease in Cx43 protein expression after application of specific antisense oligonucleotides but the abundance of a closely related protein, Connexin-32 (Cx32), was not affected. Application of antisense Cx43 ODNs at stages 8-15 HH before limb outgrowth resulted in dramatic limb phenotypes. About 40% of treated embryos exhibited defects such as truncation of the limb bud, fragmentation into two or more domains, or complete splitting of the limb bud into two or three branches. Molecular analysis of antisense treated embryos failed to detect Shh or Bmp-2 in anterior structures and suggested that extra lobes seen in nicked and split limbs were not a result of establishment of new signalling centres as found after the application of FGF to the flank. However, examination of markers for the AER showed a number of abnormalities. In severely truncated specimens we were unable to detect the expression of either Fgf-4 or Fgf-8. In both nicked and split limbs the expression of these genes was discontinuous. Down-regulation of Cx43 after the antisense application could be comparable to AER removal and results in distal truncation of the limb bud. Taken together these data suggest the existence of a feedback loop between the FGFs and signalling mediated by Cx43.  (+info)

Chemical signaling from colonic smooth muscle cells to DRG neurons in culture. (5/2680)

Transduction mechanisms between target cells within the intestinal wall and peripheral terminals of extrinsic primary afferent neurons are poorly understood. The purpose of this study was to characterize the interactions between smooth muscle cells from the rat distal colon and lumbar dorsal root ganglion (DRG) neurons in coculture. DRG neurons visually appeared to make contact with several myocytes. We show that brief mechanical stimulation of these myocytes resulted in intracellular Ca2+ concentration ([Ca2+]i) transients that propagated into 57% of the contacting neurites. Direct mechanical stimulation of DRG neurites cultured without smooth muscle had no effect. We also show that colonic smooth muscle cells express multiple connexin mRNAs and that these connexins formed functional gap junctions, as evidenced by the intercellular transfer of Lucifer yellow. Furthermore, thapsigargin pretreatment and neuronal heparin injection abolished the increase in neurite [Ca2+]i, indicating that the neuronal Ca2+ signal was triggered by inositol 1,4, 5-trisphosphate-mediated Ca2+ release from intracellular stores. Our results provide evidence for intercellular chemical communication between DRG neurites and intestinal smooth muscle cells that mediates the exchange of second messenger molecules between different cell types.  (+info)

Spatial and temporal regulation of gap junction connexin43 in vascular endothelial cells exposed to controlled disturbed flows in vitro. (6/2680)

Hemodynamic regulation of the endothelial gap junction protein connexin43 (Cx43) was studied in a model of controlled disturbed flows in vitro. Cx43 mRNA, protein expression, and intercellular communication were mapped to spatial variations in fluid forces. Hemodynamic features of atherosclerotic lesion-prone regions of the vasculature (flow separation and recirculation) were created for periods of 5, 16, and 30 h, with laminar shear stresses ranging between 0 and 13.5 dynes/cm2. Within 5 h, endothelial Cx43 mRNA expression was increased in all cells when compared with no-flow controls, with highest levels (up to 6- to 8-fold) expressed in regions of flow recirculation corresponding to high shear stress gradients. At 16 h, Cx43 mRNA expression remained elevated in regions of flow disturbance, whereas in areas of fully developed, undisturbed laminar flow, Cx43 expression returned to control levels. In all flow regions, typical punctate Cx43 immunofluorescence at cell borders was disrupted by 5 h. After 30 h of flow, disruption of gap junctions persisted in cells subjected to flow separation and recirculation, whereas regions of undisturbed flow were substantially restored to normal. These expression differences were reflected in sustained inhibition of intercellular communication (dye transfer) throughout the zone of disturbed flow (84.2 and 68.4% inhibition at 5 and 30 h, respectively); in contrast, communication was fully reestablished by 30 h in cells exposed to undisturbed flow. Up-regulation of Cx43 transcripts, sustained disorganization of Cx43 protein, and impaired communication suggest that shear stress gradients in regions of disturbed flow regulate intercellular communication through the expression and function of Cx43.  (+info)

Intracellular trafficking pathways in the assembly of connexins into gap junctions. (7/2680)

Trafficking pathways underlying the assembly of connexins into gap junctions were examined using living COS-7 cells expressing a range of connexin-aequorin (Cx-Aeq) chimeras. By measuring the chemiluminescence of the aequorin fusion partner, the translocation of oligomerized connexins from intracellular stores to the plasma membrane was shown to occur at different rates that depended on the connexin isoform. Treatment of COS-7 cells expressing Cx32-Aeq and Cx43-Aeq with brefeldin A inhibited the movement of these chimera to the plasma membrane by 84 +/- 4 and 88 +/- 4%, respectively. Nocodazole treatment of the cells expressing Cx32-Aeq and Cx43-Aeq produced 29 +/- 16 and 4 +/- 7% inhibition, respectively. In contrast, the transport of Cx26 to the plasma membrane, studied using a construct (Cx26/43T-Aeq) in which the short cytoplasmic carboxyl-terminal tail of Cx26 was replaced with the extended carboxyl terminus of Cx43, was inhibited 89 +/- 5% by nocodazole and was minimally affected by exposure of cells to brefeldin A (17 +/-11%). The transfer of Lucifer yellow across gap junctions between cells expressing wild-type Cx32, Cx43, and the corresponding Cx32-Aeq and Cx43-Aeq chimeras was reduced by nocodazole treatment and abolished by brefeldin A treatment. However, the extent of dye coupling between cells expressing wild-type Cx26 or the Cx26/43T-Aeq chimeras was not significantly affected by brefeldin A treatment, but after nocodazole treatment, transfer of dye to neighboring cells was greatly reduced. These contrasting effects of brefeldin A and nocodazole on the trafficking properties and intercellular dye transfer are interpreted to suggest that two pathways contribute to the routing of connexins to the gap junction.  (+info)

Dissection of the molecular basis of pp60(v-src) induced gating of connexin 43 gap junction channels. (8/2680)

Suppression of gap-junctional communication by various protein kinases, growth factors, and oncogenes frequently correlates with enhanced mitogenesis. The oncogene v-src appears to cause acute closure of gap junction channels. Tyr265 in the COOH-terminal tail of connexin 43 (Cx43) has been implicated as a potential target of v-src, although v-src action has also been associated with changes in serine phosphorylation. We have investigated the mechanism of this acute regulation through mutagenesis of Cx43 expressed in Xenopus laevis oocyte pairs. Truncations of the COOH-terminal domain led to an almost complete loss of response of Cx43 to v-src, but this was restored by coexpression of the independent COOH-terminal polypeptide. This suggests a ball and chain gating mechanism, similar to the mechanism proposed for pH gating of Cx43, and K+ channel inactivation. Surprisingly, we found that v-src mediated gating of Cx43 did not require the tyrosine site, but did seem to depend on the presence of two potential SH3 binding domains and the mitogen-activated protein (MAP) kinase phosphorylation sites within them. Further point mutagenesis and pharmacological studies in normal rat kidney (NRK) cells implicated MAP kinase in the gating response to v-src, while the stable binding of v-src to Cx43 (in part mediated by SH3 domains) did not correlate with its ability to mediate channel closure. This suggests a common link between closure of gap junctions by v-src and other mitogens, such as EGF and lysophosphatidic acid (LPA).  (+info)

Receptor activator of NF-kappaB ligand (RANKL) is crucial in osteoclastogenesis but signaling events involved in osteoclast differentiation are far from complete and other signals may play a role in osteoclastogenesis. A more direct pathway for cellular crosstalk is provided by gap junction intercellular channel, which allows adjacent cells to exchange second messengers, ions, and cellular metabolites. Here we have investigated the role of gap junction communication in osteoclastogenesis in mouse bone marrow cultures. Immunoreactive sites for the gap junction protein connexin 43 (Cx43) were detected in the marrow stromal cells and in mature osteoclasts. Carbenoxolone (CBX) functionally blocked gap junction communication as demonstrated by a scrape loading Lucifer Yellow dye transfer technique. CBX caused a dose-dependent inhibition (significant , or = 90 microM) of the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells formed in 7- to 8-day marrow cultures ...
The biogenesis of connexins and their assembly into functional gap junction hemichannels (connexons) was studied with the use of a cell-free transcription/translation system. Velocity sedimentation on sucrose gradients showed that a small proportion of connexin (Cx) 26 and Cx32 that were co-translationally translocated into microsomes were oligomers of Cx26 and Cx32. Chemical cross-linking studies showed that these corresponded to hexameric connexons. Reconstitution of connexons synthesized in vitro into liposomes induced permeability properties consistent with the view that open gap junction hemichannels were produced. By using an immunoprecipitation approach, a simultaneous translation of Cx26 and Cx32 incorporated into microsomes resulted in homomeric connexons. However, supplementation of the translation system in vitro with liver Golgi membranes produced heteromeric connexons constructed of Cx32 and Cx26, and also resulted in an increased oligomerization especially of Cx32. All of the ...
During blood vessel assembly, mural cell differentiation is initiated in response to contact-dependent interactions with endothelial cells.5,7 In the present studies, we demonstrate for the first time that functional gap junction channels are established between endothelial cells and the mural cell progenitors that they recruit and are necessary for endothelial-induced mural cell differentiation. We additionally determined that the mechanism by which gap junctions mediate endothelial-induced mural cell differentiation involves the activation of TGF-β, which then induces SRF and mural cell-specific gene expression.. The mesenchymal cells that did not form gap junctions with endothelial cells (Cx43−/−) did not undergo endothelial-induced differentiation toward a mural cell phenotype. Of note, the Cx43−/− cells express low levels of Cx45, although this expression was not evident as channel activity and not adequate to support the formation of functional heterocellular gap junctions with ...
Early descriptions of gap junctions and connexons did not refer to them as such and many other terms were used. It is likely that synaptic disks[117] were an accurate reference to gap junction plaques. While the detailed structure and function of the connexon was described in a limited way at the time the gross disk structure was relatively large and easily seen by various TEM techniques. Disks allowed researchers using TEM to easily locate the connexons contained within the disk like patches in vivo and in vitro. The disk or plaque appeared to have structural properties different from those imparted by the connexons alone.[26] It was thought that if the area of membrane in the plaque transmitted signals the area of membrane would have to be sealed in some way to prevent leakage.[118] Later studies showed gap junction plaques are home to non-connexin proteins making the modern usage of the terms gap junction and gap junction plaque non-interchangeable as the area of the gap ...
Reversible down-regulation of gap junctional intercellular communication (GJIC) is proposed to be an important cellular mechanism in tumor promotion. Gap junction function is modified by a variety of tumor promoters, including the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). Treatment of cells with TPA results in the activation and subsequent depletion of the TPA-responsive protein kinase C (PKC) isoforms. TPA-induced degradation of the PKC isoforms α, δ and ϵ was recently shown to occur via the ubiquitin-proteasome pathway. In the present study we investigated the role of the proteasome in the TPA-induced modification of GJIC in IAR20 rat liver epithelial cells. TPA exposure of IAR20 cells induced hyperphosphorylation of gap junction protein connexin43 and inhibition of GJIC. Prolonged TPA treatment induced down-regulation of PKCα, δ and ϵ and a reduction in the total PKC activity, which was associated with recovery of GJIC. Co-treatment of IAR20 cells with TPA and the ...
TY - JOUR. T1 - Gap junctional channels regulate acid secretion in the mammalian gastric gland. AU - Radebold, K.. AU - Horakova, E.. AU - Gloeckner, J.. AU - Ortega, G.. AU - Spray, David C.. AU - Vieweger, H.. AU - Siebert, K.. AU - Manuelidis, L.. AU - Geibel, J. P.. PY - 2001/10/1. Y1 - 2001/10/1. N2 - Gap junction channels are regarded as a primary pathway for intercellular message transfer, including calcium wave propagation. Our study identified two gap junctional proteins, connexin26 and connexin32, in rat gastric glands by RT-PCR, Western blot analysis, and immunofluorescence. We demonstrated a potential physiological role of the gap junctional channels in the acid secretory process using the calcium indicator fluo-3, and microinjection of Lucifer Yellow. Application of gastrin (10-7 M) to the basolateral membrane resulted in the induction of uniphasic calcium signals in adjacent parietal cells. In addition, single parietal cell microinjections in intact glands with the cell-impermeant ...
The mechanism by which the change in gap-junctional distribution influences the location and characteristics of the reentrant circuit has yet to be determined. The abnormal redistribution of gap junctions to the lateral interfaces between myocytes might be expected to enhance side-to-side coupling, thereby improving transverse conduction and reducing (rather than increasing) the arrhythmogenicity of the tissue by reducing the degree of anisotropy. The redistribution should, however, be considered in the context of other changes of electrophysiological significance in the infarct border zone myocytes.14 15 43 Although the functional status of the gap junctions in these border zone cells is unknown, the results of in vitro studies would suggest that the hypoxia, acidosis, and hypercalcemia that may exist in this tissue would attenuate gap-junctional coupling44 and reduce conductance particularly in the transverse direction.45 46 Indeed, one might speculate that the redistribution of gap junctions ...
TY - JOUR. T1 - Colocalization of connexin 43 and connexin 45 but absence of connexin 40 in granulosa cell gap junctions of rat ovary. AU - Okuma, A.. AU - Kuraoka, A.. AU - Iida, H.. AU - Inai, T.. AU - Wasano, K.. AU - Shibata, Y.. PY - 1996/7. Y1 - 1996/7. N2 - The expression and localization of gap junction family proteins (connexins) were examined in nonstimulated and gonadotrophin-stimulated ovarian follicles of immature rats. Immunoblot and RNA blot analysis showed the presence of connexin (Cx) 43, Cx40 and Cx45 in ovarian tissue. Of these connexin proteins, Cx43 and Cx45 were identified by immunofluorescent microscopy between granulosa cells in characteristic expression patterns related to follicular developmental stages, while Cx40 was not expressed in granulosa cells but was detected in blood vessels in ovarian stroma. In some plaques of gap junction between granulosa cells, Cx45 was found to be colocalized with Cx43. In immunofluorescent microscopy, the expression of Cx43 was ...
Early descriptions of gap junctions and connexons did not refer to them as such and many other terms were used. It is likely that synaptic disks[116] were an accurate reference to gap junction plaques. While the detailed structure and function of the connexon was described in a limited way at the time the gross disk structure was relatively large and easily seen by various TEM techniques. Disks allowed researchers using TEM to easily locate the connexons contained within the disk like patches in vivo and in vitro. The disk or plaque appeared to have structural properties different from those imparted by the connexons alone.[25] It was thought that if the area of membrane in the plaque transmitted signals the area of membrane would have to be sealed in some way to prevent leakage.[117] Later studies showed gap junction plaques are home to non-connexin proteins making the modern usage of the terms gap junction and gap junction plaque non-interchangeable as the area of the gap ...
Cxs (connexins), the protein subunits forming gap junction intercellular communication channels, are transported to the plasma membrane after oligomerizing into hexameric assemblies called connexin hemichannels (CxHcs) or connexons, which dock head-to-head with partner hexameric channels positioned on neighbouring cells. The double membrane channel or gap junction generated directly couples the cytoplasms of interacting cells and underpins the integration and co-ordination of cellular metabolism, signalling and functions, such as secretion or contraction in cell assemblies. In contrast, CxHcs prior to forming gap junctions provide a pathway for the release from cells of ATP, glutamate, NAD+ and prostaglandin E2, which act as paracrine messengers. ATP activates purinergic receptors on neighbouring cells and forms the basis of intercellular Ca2+ signal propagation, complementing that occuring more directly via gap junctions. CxHcs open in response to various types of external changes, including ...
My research interests focus on gap junctions which are involved in cell-to-cell communication. Regulating the chemical and physical properties of gap junctions are the different connexin proteins. Unique communication compartments can be formed when gap junctions are assembled from various connexins.. Presently, I am examining the implications of gap junctions on cell differentiation and development using the testis as a model. Organized in the seminiferous tubule and supported by Sertoli cells are some 63 different germ cell types. The germ cells are arranged and organized in the seminiferous epithelium for an ordered development and differentiation into spermatozoa. We are currently determining gap junctions role in the formation of specific communication compartments and how gap junctions regulate and support specific spermatogenic cells. Gap junction assembly, connexin composition, and the chemical and physical properties of homotypic - heterotypic gap junctions will be examined ...
Introduction: Metastasis involves the emigration of tumor cells through the vascular endothelium, a process also known as diapedesis. The molecular mechanisms regulating tumor cell diapedesis are poorly understood, but may involve heterocellular gap junctional intercellular communication (GJIC) between tumor cells and endothelial cells. Method: To test this hypothesis we expressed connexin 43 (Cx43) in GJIC-deficient mammary epithelial tumor cells (HBL100) and examined their ability to form gap junctions, establish heterocellular GJIC and migrate through monolayers of human microvascular endothelial cells (HMVEC) grown on matrigel-coated coverslips. Results: HBL100 cells expressing Cx43 formed functional heterocellular gap junctions with HMVEC monolayers within 30 minutes. In addition, immunocytochemistry revealed Cx43 localized to contact sites between Cx43 expressing tumor cells and endothelial cells. Quantitative analysis of diapedesis revealed a two-fold increase in diapedesis of Cx43 expressing
PURPOSE To establish an electrical fingerprint for the gap junction channels between mammalian lens epithelial cells. METHODS The double whole cell patch clamp technique was applied to isolated cell pairs obtained from mouse lens epithelium and a continuous cell line of lens epithelial cells derived from the sheep lens (SLE 2.1). RESULTS The junctional conductance in mouse lens epithelial cells and in cultured SLE 2.1 cells was found to be moderately voltage dependent. SLE 2.1 cells were analyzed in more detail. The voltage dependence could be described by a Boltzmann distribution with Vo = +/- 63.1 mV and Gmin = 0.34. In cell pairs that exhibited spontaneously low junctional conductance, single channel events could be distinguished. Single gap junction channel currents had a linear current-voltage relationship. A frequency histogram of single channel conductances from eight cell pairs had three major peaks of 35, 60 and 97 pS. CONCLUSION The electrical properties of gap junction channels
Gap junction channels allow communication in the form of small molecules that flow between adjacent cells. Conductance through gap junctions formed of the connexin43 (Cx43) protein is decreased after stimulation of G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptors (GPCRs) at the cell surface, but the actual mechanism of channel regulation has been unclear. van Zeijl et al. report that in Rat-1 fibroblasts, one way gap junction conductance can be regulated is through changes in the abundance of the phospholipid phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2]. The authors confirmed decreased conductance of gap junctions formed from Cx43 in cells transfected with an active form of the G protein alpha subunit Gαq. Gαq activates phospholipase C-β (PLC-β), which catalyzes hydrolysis of PtdIns(4,5)P2, forming the second messengers inositol 1,4,5-trisphosphate (IP3) and diacylglycerol, and experiments with a fluorescently labeled probe containing a pleckstrin ...
TY - JOUR. T1 - Glycosaminoglycans and proteoglycans induce gap junction expression and restore transcription of tissue‐specific mRNAs in primary liver cultures. AU - Fujita, Michiyasu. AU - Spray, David C.. AU - Choi, Haing. AU - Saez, Juan C.. AU - Watanabe, Tohru. AU - Rosenberg, Larry C.. AU - Hertzberg, Elliott L.. AU - Reid, Lola M.. PY - 1987/1/1. Y1 - 1987/1/1. N2 - Normal rat hepatocytes maintained on tissue culture plastic and in serum‐supplemented medium lose their gap junctions within 12 hr and expression of their tissue‐specific functions within 24 to 72 hr. The gap junctions are lost via internalization and degradation, and the differentiated functions due to loss of synthesis and to rapid degradation of tissue‐specific mRNAs. Near normal levels of tissue‐specific mRNAs can be achieved by stabilization of the mRNAs but not by transcription (for most genes), if the cells are cultured in a serum‐free, hormonally defined medium and on substrata of tissue culture plastic, ...
Gap junctions are clusters of specialized intercellular channels that regulate the direct exchange of ions and various hydrophilic cellular metabolites that are smaller than 1000 Da, a process known as gap junctional intercellular communication (GJIC) (Alexander and Goldberg, 2003). Two inter-docked connexons (hemichannels), one from each of two apposing cells, form a functional gap junction channel. Each connexon is composed of six oligomerized connexin (Cx) subunits, and, to date, the connexin family consists of 21 members in human (Söhl and Willecke, 2003; Söhl and Willecke, 2004). Interestingly, the primary function of gap junction channels is to facilitate intercellular communication; however, hemichannels have also been reported to exist and function at the cell surface in an undocked state, permitting the transfer of molecules between extracellular and intracellular environments (Anselmi et al., 2008; Burra and Jiang, 2011; Tong et al., 2007). Hemichannels that are formed from single or ...
Upregulation of gap junctional intercellular communication and connexin 43 expression by cyclic-AMP and all-trans-retinoic acid is associated with glutathione depletion and chemosensitivity in neuroblastoma cells.
Gap junctions contain intercellular channels that allow direct communication between the cytosolic compartments of adjacent cells. Each gap junction channel is formed by docking of two hemichannels, each containing six connexins, contributed by each neighboring cell. These channels permit the direct transfer of small molecules including ions, amino acids, nucleotides, second messengers and other metabolites between adjacent cells. Gap junctional communication is essential for many physiological events, including embryonic development, electrical coupling, metabolic transport, apoptosis, and tissue homeostasis. Communication through Gap Junction is sensitive to a variety of stimuli, including changes in the level of intracellular Ca2+, pH, transjunctional applied voltage and phosphorylation/dephosphorylation processes. This figure represents the possible activation routes of different protein kinases involved in Cx43 and Cx36 phosphorylation ...
Gap junctions contain intercellular channels that allow direct communication between the cytosolic compartments of adjacent cells. Each gap junction channel is formed by docking of two hemichannels, each containing six connexins, contributed by each neighboring cell. These channels permit the direct transfer of small molecules including ions, amino acids, nucleotides, second messengers and other metabolites between adjacent cells. Gap junctional communication is essential for many physiological events, including embryonic development, electrical coupling, metabolic transport, apoptosis, and tissue homeostasis. Communication through Gap Junction is sensitive to a variety of stimuli, including changes in the level of intracellular Ca2+, pH, transjunctional applied voltage and phosphorylation/dephosphorylation processes. This figure represents the possible activation routes of different protein kinases involved in Cx43 and Cx36 phosphorylation ...
Objective: Gap junctions (formed by connexins, Cx) are important for functional coordination of cells in the vascular wall. However, little is known about their physiological regulation in this tissue. We examined the effects of nitric oxide (NO), an important mediator of vasomotion, wound healing and angiogenesis, on the formation of gap junctions in endothelial cells (human umbilical vein endothelial cells, HUVEC). Methods: Flow cytometry was used to determine dye transfer through newly formed gap junctions between acutely coincubated HUVECs. Parallel experiments in wild-type HeLa cells (no connexins) and transfected HeLa cells exclusively expressing Cx43, Cx40 or Cx37 were performed to determine the specific role of Cx subtypes. The intracellular distribution of Cx40 was examined after fractionation with triton by Western blotting. Intracellular levels of cGMP and cAMP were measured by radioimmunoassay. Results: The NO donor SNAP (1 μM) enhanced gap-junctional coupling in HUVECs by about ...
Connexin 47 (Cx47), and to a lesser extent Cx32, are assembled into Gap Junctions (GJs) and couple oligodendrocytes mainly to astrocytes via heterotypic GJs and to other oligodendrocytes via homotypic GJs. In the demyelinating and inflammatory disease Multiple Sclerosis (MS) these oligodendrocyte connexins appear disrupted. Recently published studies in our lab utilizing mice with Experimental Autoimmune Encephalomyelitis (EAE), a mouse model of MS, demonstrates that the absence of Cx32 or Cx47 affects the severity and progression of the disease and alters the profile of several CNS-inflammation-related cytokines. From these 64 cytokines tested in wild type (WT) EAE, Cx32-knockout (KO) EAE, and Cx47-KO EAE mice, we selected the most relevant and altered molecules, GM-CSF, G-CSF, CCL2, and VCAM-1 for further testing in the same mouse genotypes. Their expression was analyzed at 7, 12, and 24 days post injection (dpi) using fluorescent microscopy, real-time PCR, and Western blot analysis. This ...
TY - JOUR. T1 - Intercellular communication and human hepatocellular carcinoma. AU - Carruba, Giuseppe. AU - Cocciadiferro, Letizia. AU - Bellavia, Vincenzo. AU - Rizzo, Sergio. AU - Tsatsanis, Christos. AU - Spandidos, Demetrios. AU - Muti, Paola. AU - Smith, Colin. AU - Mehta, Parmender P. AU - Castagnetta, Luigi. PY - 2004/1/1. Y1 - 2004/1/1. N2 - We have previously reported that gap junction-mediated intercellular communication (GJIC) can be restored in junctionally deficient human prostate epithelial cells, also suggesting that GJIC activity is regulated by estrogen. In the present work, we report studies on sex steroid regulation of GJIC and proliferative activity in both nontumoral (Chang liver, CL) and malignant (HepG2, Huh7) human liver cells. Junctional activity and liver cell growth were measured using the scrape-loading/dye-transfer (SL/DT) and the MTS assay, respectively. Using the SL/DT, only Huh7 cells exhibited a moderate degree of Junctional activity in basic conditions, while ...
There is a reduction in the 28-kD gap junction protein detectable by immunofluorescence in livers of partially hepatectomized rats and in cultured hepatocytes stimulated to proliferate. By the coordinate use of antibodies directed to the hepatic junction protein (HJP28) and the use of a monoclonal antibody that recognizes bromodeoxyuridine (BrdU) incorporated into DNA, we have been able to study the relationship between detectable gap junction protein and cell division. Hepatocytes that label with BrdU in the regenerating liver and in cell culture show a significant reduction of HJP28. Cells that do not synthesize DNA, on the other hand, show normal levels and distribution of immunoreactive gap junction protein. We postulate that the quantitative changes in gap junction expression might play an important role in the control of proliferation in the liver.
Using an in vitro model in which a confluent monolayer of capillary endothelial cells is mechanically wounded, gap junction-mediated intercellular communication has been studied by loading the cells with the fluorescent dye, Lucifer Yellow. Approximately 40-50% of the cells in a nonwounded confluent monolayer were coupled in groups of four to five cells (basal level). Basal levels of communication were also observed in sparse and preconfluent cultures, but were reduced in postconfluent monolayers. 30 min after wounding, coupling was markedly reduced between cells lining the wound. Communication at the wound was partially reestablished by 2 h, exceeded basal levels after 6 h and reached a maximum after 24 h, at which stage approximately 90% of the cells were coupled in groups of six to seven cells. When the wound had closed (after 8 d), the increase in communication was no longer observed. Induction of wound-associated communication was unaffected by exposure of the cells to the DNA synthesis ...
Gap junctions are specialized cell-cell contacts that provide direct intercellular communication between eukaryotic cells. The tyrosine-sorting signal (YXXØ), present at amino acids 286-289 of Cx43 (connexin43), has been implicated in the internalization of the protein. In recent years, ubiquitination of Cx43 has also been proposed to regulate gap junction intercellular communication; however, the underlying mechanism and molecular players involved remain elusive. In the present study, we demonstrate that ubiquitinated Cx43 is internalized through a mechanism that is independent of the YXXØ signal. Indeed, expression of a Cx43-Ub (ubiquitin) chimaera was shown to drive the internalization of a mutant Cx43 in which the YXXØ motif was eliminated. Immunofluorescence, cycloheximide-chase and cell-surface-protein biotinylation experiments demonstrate that oligomerization of Cx43-Ub into hemichannels containing wild-type Cx43 or mutant Cx43Y286A is sufficient to drive the internalization of the ...
Gap junction protein that acts as a regulator of bladder capacity. A gap junction consists of a cluster of closely packed pairs of transmembrane channels, the connexons, through which materials of low MW diffuse from one cell to a neighboring cell. May play a critical role in the physiology of hearing by participating in the recycling of potassium to the cochlear endolymph. Negative regulator of bladder functional capacity: acts by enhancing intercellular electrical and chemical transmission, thus sensitizing bladder muscles to cholinergic neural stimuli and causing them to contract. May play a role in cell growth inhibition through the regulation of NOV expression and localization. Plays an essential role in gap junction communication in the ventricles (By similarity).
Gap junction protein that acts as a regulator of bladder capacity. A gap junction consists of a cluster of closely packed pairs of transmembrane channels, the connexons, through which materials of low MW diffuse from one cell to a neighboring cell. May play a critical role in the physiology of hearing by participating in the recycling of potassium to the cochlear endolymph. Negative regulator of bladder functional capacity: acts by enhancing intercellular electrical and chemical transmission, thus sensitizing bladder muscles to cholinergic neural stimuli and causing them to contract. May play a role in cell growth inhibition through the regulation of NOV expression and localization. Plays an essential role in gap junction communication in the ventricles (By similarity).
Evidence implicating alterations in connexin43 gap junctions in arrhythmogenesis in different models of human heart disease has steadily accumulated.20 21 22 26 29 30 The novel findings of the present study are that (1) a reduction in connexin43 gap junctions occurs in hibernating myocardium beyond that seen in reversible ischemia, and (2) a specific feature characterizing hibernating myocardium is a loss of the population of large gap junctions at the disk periphery. These changes seen by laser scanning immunoconfocal microscopy were subsequently confirmed by quantification with PC image analysis. The use of quantitative immunofluorescence for measurement of gap junction size has been previously validated with a polyclonal anti-connexin43 antibody in rat left ventricular tissue by comparison of measurements from immunoconfocal (0.53 μm) and freeze-fracture (0.57 μm) electron microscopy.28 In the present study, quantification of images obtained with a different primary antibody yielded a mean ...
Our results demonstrate changes of gap junction channel characteristics and alterations in the pathways of intercellular communication in the organ of Corti during postnatal development. The characteristics of early postnatal GJIC bear little resemblance to those in the hearing cochlea. These observations have implications for the interpretation of studies of GJIC in normal hearing and disease. We have provided functional evidence for the existence of gap junction channels comprising heteromeric Cx26/Cx30 connexons in native cochlear tissue in hearing animals based on the selective transfer of diagnostic dyes, in conjunction with the colocalization of Cx26 and Cx30 within supporting cells. We found evidence for Cx26-only channels (i.e., LY permeable) only in peripheral supporting cells within the organ of Corti in hearing animals (supplemental Fig. 4, available at www.jneurosci.org as supplemental material). Furthermore, we have provided functional and anatomical evidence that is consistent with ...
Guys, Ive uploaded my disease stuff except im having problems with uploading the references and pictures. WIll try again later. Ive also added a few things to our glossary. Anyway hope youve all had a good break! --Elizabeth Blanchard 10:28, 30 April 2011 (EST) I found another article concerning disease that might be of use: Gap-Junction Channels Dysfunction in Deafness and Hearing Loss I wouldnt put the abstract since its too long. [1] --z3283837 23:00, 26 April 2011 (EST) Hey guys, I am kind of finished with my part for the intro and the function although it needs a little bit of touch up. Anyway, while researching, I just found a few review articles that might be helpful. Whoever is doing the location of gap junctions, this article below gives you an overview of the expression patterns of different connexins in different tissues. Diversity and properties of connexin gap junction channels Gap junction channels are composed of two apposing hemichannels (connexons) in the contiguous cells ...
Guys, Ive uploaded my disease stuff except im having problems with uploading the references and pictures. WIll try again later. Ive also added a few things to our glossary. Anyway hope youve all had a good break! --Elizabeth Blanchard 10:28, 30 April 2011 (EST) I found another article concerning disease that might be of use: Gap-Junction Channels Dysfunction in Deafness and Hearing Loss I wouldnt put the abstract since its too long. [1] --z3283837 23:00, 26 April 2011 (EST) Hey guys, I am kind of finished with my part for the intro and the function although it needs a little bit of touch up. Anyway, while researching, I just found a few review articles that might be helpful. Whoever is doing the location of gap junctions, this article below gives you an overview of the expression patterns of different connexins in different tissues. Diversity and properties of connexin gap junction channels Gap junction channels are composed of two apposing hemichannels (connexons) in the contiguous cells ...
Purpose: Cancer patients are often concurrently treated with analgesics and antineoplastic drugs, yet the influence of analgesic agents on therapeutic activity of antineoplastic drugs is largely unexplored. This study investigates the effects of three commonly used analgesics, which produce analgesia by different mechanisms, on cytotoxicity induced by cisplatin, a widely used antitumor agent, and the relation between those effects and modulation of gap junction function by the analgesics.. Experimental Design: The role of gap junctions in the modulation of cisplatin toxicity is explored by manipulation of connexin expression, and gap junction presence and function, using clinically relevant concentrations of the analgesics and cisplatin.. Results: Short-term exposure of transformed cells to cisplatin reduced the clonogenic survival in low-density cultures (without gap junction formation) and in high density (with gap junction formation), but the toxic effect was greater at high density. In the ...
Ng, FS, Lyon, AR, Shadi, IT, Chang, ETY, Chowdhury, RA, Dupont, E and Peters, NS (2010) GAP JUNCTIONAL UNCOUPLING WITH CARBENOXOLONE SLOWS CONDUCTION AND INCREASES VULNERABILITY TO VENTRICULAR ARRHYTHMIAS IN STRUCTURALLY NORMAL HEARTS: AN OPTICAL MAPPING STUDY In: Annual Conference and Exhibition of the British-Cardiovascular-Society, 2010-06-07 - 2010-06-09, Manchester, ENGLAND. Ng, FS, Lyon, AR, Shadi, IT, Chang, ETY, Chowdhury, RA, Dupont, E and Peters, NS (2010) MODULATION OF GAP JUNCTIONAL COUPLING AS AN ANTI-ARRHYTHMIC STRATEGY TO PREVENT REPERFUSION VENTRICULAR ARRHYTHMIAS In: Annual Conference and Exhibition of the British-Cardiovascular-Society, 2010-06-07 - 2010-06-09, Manchester, ENGLAND. Dhillon, PS, Gray, R, Kojodjojo, P, Jabr, R, Chowdhury, RA, Fry, CH and Peters, NS (2009) The Relationship Between Gap Junction Conductance and Conduction Velocity in Intact Myocardium In: 82nd Scientific Session of the American-Heart-Association, 2009-11-14 - 2009-11-18, Orlando, FL. Dhillon, P, ...
The molecular basis of gap junctions in invertebrates has been a mystery for decades. Connexin proteins were first identified in the 1970s as the structural components of gap junctions in vertebrates (Goodenough, 1974). For more than 20 years, the term `connexin became synonymous with gap junctions, whereas efforts to find the homologous connexin in invertebrates were unsuccessful (Phelan et al., 1998). It was only in 1998 that the gene family encoding invertebrate gap-junction proteins, innexins, was first confirmed in Drosophila (Phelan et al., 1998). To date, eight innexin genes have been found in the fruit fly, and 25 innexin genes in C. elegans (Phelan, 2005).. In the present study we identify six innexin-like genes in Aedes (Table 5). The neighbor-joining tree (Fig. 9) shows that most of the innexins in Aedes are still closely related to their Drosophila homologues despite the 250 million years of evolution that separate the mosquito from the fruit fly (Severson et al., 2004). The strong ...
Several laboratories have demonstrated a decrease in gap junctional communication in cells transformed by the src oncogene of the Rous sarcoma virus. The decrease In gap junctional communication was associated with tyrosine phosphorylation of the gap junction protein, connexin43 (Cx43). This study was initiated to determine if the phosphorylation of Cx43 is the result of a direct kinase-substrate interaction between the highly active tyrosine kinase, pp60v-src, and Cx43. Confocal microscopy data indicates that the two proteins are within physical proximity allowing for a potential kinase-substrate interaction. Previous biochemical studies have been limited by the low levels of Cx43 protein in fibroblast cell lines. To obtain larger quantities of Cx43 we constructed a recombinant baculovirus expressing Cx43 in Spodoptera frugiperda (Sf-9) cells and subsequently purified the expressed Cx43 by immunoaffinity chromatography. We observed that this partially-purified Cx43 was phosphorylated on ...
Heart failure (HF), whether nonischemic or ischemic, is associated with a nearly 50% incidence of sudden death, primarily from ventricular tachycardia (VT) degenerating to ventricular fibrillation (VF).1 Whereas VT in nonischemic HF initiates primarily by a nonreentrant mechanism,2 myocardium from patients with idiopathic dilated cardiomyopathy (IDCM) exhibits nonuniform anisotropy, slow conduction, and conduction block3 that could underlie reentry during the transition from VT to VF. Conduction slowing could arise from decreased depolarizing currents and/or decreased gap junctional coupling.4 However, the degree of slow conduction and block in failing myocardium appears to be out of proportion to the changes in active membrane properties.5 Moreover, LV myocytes from an animal model of nonischemic HF exhibit markedly decreased gap junctional conductance.6 Thus, alterations in intercellular coupling involving cardiac gap junctions may underlie slow conduction in nonischemic HF.. Gap junctions are ...
New immunolocalization data put the role of the lens MP26 (MIP) protein in a new perspective. During maturation of lens fibre cells, MIP is found to associate specifically with two structures, gap junctions and cell interlocking processes (known as ball and socket domains). It is significant that the zone in which these associations are most striking is discrete, coinciding with the zone of rapidly enlarging junctional plaques and newly forming ball and socket domains. Observation of domain-specific interactions of MIP with forming gap junctions and ball and socket domains suggests that MIP may be involved in the formation of close membrane appositions. Furthermore, previous ambiguities in the literature over the presence of MIP in gap junctions are clarified by the knowledge that, in situ, MIP associates strongly with gap junctions for only a brief period (with less than about 5% of all lens gap junctions at any one time) during the assembly of junctional plaques. ...
Model of the role of FGF in establishing regional differences in gap junction-mediated intercellular communication in the lens. (A) The concentration of FGF i
Intracellular calcium (Ca2+) concentration exhibits periodic oscillations in vascular smooth muscle cells. This is thought to result from Ca2+ release from intracellular stores, due to inositol triphosphate and ryanodine-sensitive channel activation. This activation has been shown to result in either Ca2+ sparks, highly localized calcium increases, or waves, global Ca2+ increase that propagates the length of the cell.[3] To allow vasomotion to occur, synchronization must occur between the individual oscillations, resulting in global calcium synchronization and vessel tone oscillation.[4] Gap junctions are thought to play a large role in this synchronization, as application of gap junction blockers has been shown to abolish vasomotion, indicating a critical role.[5] Due to regional variations in gap junction distribution and coupling (homocellular vs. heterocellular) several hypotheses have been suggested to account for vasomotion occurrence. The classic mechanism of vasomotion generation ...
In the present study, we provide experimental evidence that gap junctions/hemichannels are involved in the apical phase of interkinetic nuclear migration in neural precursors. Our data suggest that regulation of apically directed interkinetic nuclear migration by intracellular Ca2+ signaling via both ATP release and Ca2+-mobilizing messenger diffusion may be an important mechanism by which functional gap junctions/hemichannels maintain the neural progenitor pool during their division.. Cytosolic Ca2+ signaling has previously been implicated in several aspects of nervous system development, including cell proliferation (Weissman et al., 2004; Pearson et al., 2005), differentiation (Gu and Spitzer, 1995), migration (Komuro and Rakic, 1993), neurite outgrowth, and growth cone behavior (Gomez and Spitzer, 1999). In the present study, we confirmed the existence of Ca2+ signaling fluctuations in neural precursors of the VZ/SVZ (Owens and Kriegstein, 1998; Weissman et al., 2004). However, in addition, ...
When DArcy Wentworth Thompsons On Growth and Form was published 100 years ago, it raised the question of how biological forms arise during development and across evolution. In light of the advances in molecular and cellular biology since then, a succinct modern view of the question states: how do genes encode geometry? Our new special issue is packed with articles that use mathematical and physical approaches to gain insights into cell and tissue patterning, morphogenesis and dynamics, and that provide a physical framework to capture these processes operating across scales.. Read the Editorial by guest editors Thomas Lecuit and L. Mahadevan, as they provide a perspective on the influence of DArcy Thompsons work and an overview of the articles in this issue.. ...
Gap junctions provide direct electrical and biochemical communication between cardiomyocytes in the heart. Connexin40 (Cx40) is the major connexin in the atria of the heart and little is known regarding its regulation. Thus, the goal was to investigate the regulation of Cx40 in both physiological and pathophysiological conditions. The first objective of this thesis was to determine whether Cx40 gap junctions were regulated by â-adrenergic receptor activation. Cx40 has previously been shown to be acutely activated by cAMP, this cAMP-induced increase in Cx40-mediated cell-to-cell dye transfer has been shown to be effected through the â-adrenergic receptor-adenylyl cyclase- Protein Kinase A (PKA) pathway in Cx40-transfected HeLa cells. The second objective of this thesis was to determine whether Cx40 gap junctions were regulated by intracellular Ca2+ concentration ([Ca2+]i ). [Ca2+]i was increased by addition of the ionophore ionomycin and elevating extracellular calcium [Ca2+]o from 1.8 mM to 21.8 mM.
Gap junctions (GJs) are expressed in most cell types of the nervous system, including neuronal stem cells, neurons, astrocytes, oligodendrocytes, cells of the blood brain barrier (endothelial cells and astrocytes) and under inflammatory conditions in microglia/macrophages. GJs connect cells by the docking of two hemichannels, one from each cell with each hemichannel being formed by 6 proteins named connexins (Cx). Unapposed hemichannels (uHC) also can be open on the surface of the cells allowing the release of different intracellular factors to the extracellular space. GJs provide a mechanism of cell-to-cell communication between adjacent cells that enables the direct exchange of intracellular messengers, such as calcium, nucleotides, IP(3), and diverse metabolites, as well as electrical signals that ultimately coordinate tissue homeostasis, proliferation, differentiation, metabolism, cell survival and death. Despite their essential functions in physiological conditions, relatively little is ...
While a number of different gap junction proteins have now been identified, hepatic gap junctions are unique in being the first demonstrated case where two homologous, but distinct, proteins (28,000 and 21,000 Mr) are found within a single gap junctional plaque (Nicholson, B. J., R. Dermietzel, D. Teplow, O. Traub, K. Willecke, and J.-P. Revel. 1987. Nature [Lond.]. 329:732-734). The cDNA for the major 28,000-Mr component has been cloned (Paul, D. L. 1986. J. Cell Biol. 103:123-134) (Kumar, N. M., and N. B. Gilula. 1986. J. Cell Biol. 103:767-776) and, based on its deduced formula weight of 32,007, has been designated connexin 32 (or Cx32 as used here). We now report the selection and characterization of clones for the second 21,000-Mr protein using an oligonucleotide derived from the amino-terminal protein sequence. Together the cDNAs represent 2.4 kb of the single 2.5-kb message detected in Northern blots. An open reading frame of 678 bp coding for a protein with a calculated molecular mass of ...
Effects of second messengers on gap junctional intercellular communication of ovine luteal cells throughout the estrous cycle.: Corpora lutea (CL) from Days 5,
In the present study we demonstrated, by various experimental approaches, that cAMP and PKC are involved in the modulation of inter-TEC GJIC: the cAMP agonist 8-Br-cAMP enhanced inter-TEC coupling whereas PMA-induced PKC activation triggered an opposite effect.. Using flow cytometry we first detected in a mouse TEC line, that up to 90% of DiIc18(3)+ cells co-cultured in 1:1 ratio with calcein+ cells became double positive, a phenomenon which was readily inhibited by the gap junction inhibitors 18-β-glycyrrhetinic acid and carbenoxolone. This result clearly demonstrates that the thymic epithelium spontaneously forms a GJIC-dependent functional syncytium in vitro. Under these conditions, 8-Br-cAMP and forskolin did not significantly modify this spontaneous percentage of coupled cells. However, both compounds enhanced up to 3 fold the calcein fluorescence intensity of the double positive cells, indicating an increase in the rate of dye transfer among coupled cells. Importantly, 8-Br-cAMP also ...
TY - JOUR. T1 - Molecular cloning and functional expression of mouse connexin-30, a gap junction gene highly expressed in adult brain and skin. AU - Dahl, Edgar. AU - Manthey, Dieter. AU - Chen-Izu, Ye. AU - Schwarz, Hans Jürgen. AU - Chang, Young Sook. AU - Lalley, Peter A.. AU - Nicholson, Bruce J.. AU - Willecke, Klaus. PY - 1996. Y1 - 1996. N2 - A new gap junction gene isolated from the mouse genome codes for a connexin protein of 261 amino acids. Because of its theoretical molecular mass of 30.366 kDa, it is named connexin-30. Within the connexin gene family, this protein is most closely related to connexin-26 (77% amino acid sequence identity). The coding region of mouse connexin-30 is uninterrupted by introns and is detected in the mouse genome as a single copy gene that is assigned to mouse chromosome 14 by analysis of mouse x hamster somatic cell hybrids. Abundant amounts of connexin-30 mRNA (two transcripts of 2.0 and 2.3 kilobase pairs) were found after 4 weeks of postnatal ...
Read Connexin Composition in Apposed Gap Junction Hemiplaques Revealed by Matched Double-Replica Freeze-Fracture Replica Immunogold Labeling, The Journal of Membrane Biology on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
Peripheral sensory ganglia contain the somata of neurons mediating mechanical, thermal, and painful sensations from somatic, visceral, and oro-facial organs. Each neuronal cell body is closely surrounded by satellite glial cells (SGCs) that have properties and functions similar to those of central astrocytes, including expression of gap junction proteins and functional dye coupling. As shown in other pain models, after systemic pain induction by intra-peritoneal injection of lipopolysaccharide, dye coupling among SGCs in intact trigeminal ganglion was enhanced. Moreover, neuron-neuron and neuron-SGC coupling was also detected. To verify the presence of gap junction-mediated coupling between SGCs and sensory neurons, we performed dual whole cell patch clamp recordings from both freshly isolated and short term cultured cell pairs dissociated from mouse trigeminal ganglia. Bidirectional gap junction mediated electrical responses were frequently recorded between SGCs, between neurons and between ...
The usage of stem cells is a promising strategy for the repair of damaged tissue in the injured brain. Recently, amniotic fluid (AF) cells have received a lot of attention as an alternative source of stem cells for cell-based therapies. However, the
The effect of SV40 viral transformation of human fibroblasts on intercellular gap junctional communication (IJC) was investigated using a short-term quantitative assay. IJC was measured using metabolic cooperation in a coculture system of argininosuccinate synthetase- and argininosuccinate lyase-deficient human fibroblasts. These cell lines were transformed with origin-defective adenovirus/SV40 recombinant virions, and IJC was determined both between transformed cells (homologous IJC) and between transformed and untransformed cells (heterologous IJC). At equivalent cell densities, homologous IJC between transformed cells was reduced to 25-55% of the level between untransformed cells. Intermediate levels of IJC (50-70% of normal) were observed in heterologous cocultures of transformed with untransformed cells. Transformed and untransformed cells were equally sensitive to inhibition of IJC by phorbol esters and by glycyrrhetinic acid, and also did not differ in the degree of upregulation of IJC by
Atherosclerosis is a chronic inflammatory disease characterised by the accumulation of monocytic cells and lipids within the sub-endothelial space by direct monocyte to endothelial cell contact through gap junctions (GJs). Both cell types express connexin 43 (Cx43) isoforms that permit the formation of GJs. This is enhanced by adhesion molecules in the presence of pro-inflammatory stimuli, such as tumour necrosis factor α (TNF-α). TNF-α is suggested to have a role in Cx43 expression mainly mediated through MAPK pathways over other intercellular pathways; however, to date the mechanism remains unclear. Experiments were carried out in the absence and presence of 25ng/ml TNF-α and the functional integrity of human umbilical vein endothelial cell (HUVEC) monolayers was assessed by measuring the trans-endothelial electrical resistance (TEER). The trans-endothelial migration (TEM) assay used as a model for the transmigration of monocytes to the sub-endothelial space. Monocytes were added to HUVEC ...
Efficient inter-myocyte communication is essential for synchronised myocardial contraction. Gap junctions are areas where adjacent cell membranes are more closely apposed to each other. Within these gap junctions are present communication ports called connexins. Connexin channels are composed of two grummet shaped hemi-channels called connexons. Each connexon in turn is a hexamer of 6 connexin protein molecules. Connexin channels are selectively permeable to certain ions and molecules less than 1kDa in weight and less than 2nm in diameter. There are three isotypes of connexins expressed by the human myocardium, connexin-40 (Cx40), connexin-43 (Cx43), and connexin-45 (Cx45). Each isotype has distinct unitary conductance, permeability, and gating properties. Cx40 are high conductance channels expressed by atrial myocytes and the conduction system. Cx43 is mainly expressed by ventricular and to a lesser extent by atrial myocytes. Cx45 are low conductance channels mainly expressed by myocytes in the ...
TY - JOUR. T1 - Control of single-molecule junction conductance of porphyrins via a transition-metal center. AU - Liu, Zhen Fei. AU - Wei, Sujun. AU - Yoon, Hongsik. AU - Adak, Olgun. AU - Ponce, Ingrid. AU - Jiang, Yivan. AU - Jang, Woo Dong. AU - Campos, Luis M.. AU - Venkataraman, Latha. AU - Neaton, Jeffrey B.. PY - 2014/9/10. Y1 - 2014/9/10. N2 - Using scanning tunneling microscope break-junction experiments and a new first-principles approach to conductance calculations, we report and explain low-bias charge transport behavior of four types of metal-porphyrin-gold molecular junctions. A nonequilibrium Greens function approach based on self-energy corrected density functional theory and optimally tuned range-separated hybrid functionals is developed and used to understand experimental trends quantitatively. Importantly, due to the localized d states of the porphyrin molecules, hybrid functionals are essential for explaining measurements; standard semilocal functionals yield qualitatively ...
1) Gap junction hyper-neurons. Stuart: Regarding my suggestion that gap junction-connected neurons (hyper-neurons) may be the neural correlate of consciousness, Christof raises the issue of connexin-36 (a brain gap junction protein) knockout mice who appear relatively normal from a cognitive standpoint, and are presumably conscious. (This exact point was debated on PSYCHE-B a year or so ago, raised by Johnjoe MacFadden). Christof notes that gamma synchrony continued in the knockout mice, though reduced.. As Christof notes, there at least ten types of connexins. Additional connexins are being discovered all the time. Further, another family of gap junction proteins - the pannexins - has been uncovered. So when Christof says: The most important connexin of the adult brain is Cx36, this is not necessarily the case. And to say that connexin-36 knockout mice lack functional gap junctions in their brains is an extremely weak contention (e.g. shown by the occurrence of even weak gamma synchrony). ...
1) Gap junction hyper-neurons. Stuart: Regarding my suggestion that gap junction-connected neurons (hyper-neurons) may be the neural correlate of consciousness, Christof raises the issue of connexin-36 (a brain gap junction protein) knockout mice who appear relatively normal from a cognitive standpoint, and are presumably conscious. (This exact point was debated on PSYCHE-B a year or so ago, raised by Johnjoe MacFadden). Christof notes that gamma synchrony continued in the knockout mice, though reduced.. As Christof notes, there at least ten types of connexins. Additional connexins are being discovered all the time. Further, another family of gap junction proteins - the pannexins - has been uncovered. So when Christof says: The most important connexin of the adult brain is Cx36, this is not necessarily the case. And to say that connexin-36 knockout mice lack functional gap junctions in their brains is an extremely weak contention (e.g. shown by the occurrence of even weak gamma synchrony). ...
TY - JOUR. T1 - Correlations of differentially expressed gap junction connexins cx26, cx30, cx32, cx43 and cx46 with breast cancer progression and prognosis. AU - Teleki, Ivett. AU - Szász, A.. AU - Maros, Mate Elod. AU - Györffy, B.. AU - Kulka, J.. AU - Meggyeshazi, Nora. AU - Kiszner, Gergo. AU - Balla, Peter. AU - Samu, Aliz. AU - Krenács, T.. PY - 2014/11/10. Y1 - 2014/11/10. N2 - Background and Aims: Connexins and their cell membrane channels contribute to the control of cell proliferation and compartmental functions in breast glands and their deregulation is linked to breast carcinogenesis. Our aim was to correlate connexin expression with tumor progression and prognosis in primary breast cancers.Materials and Methods: Meta-analysis of connexin isotype expression data of 1809 and 1899 breast cancers from the Affymetrix and Illumina array platforms, respectively, was performed. Expressed connexins were also monitored at the protein level in tissue microarrays of 127 patients equally ...
Abstract: Heart development is a precisely harmonized process of cellular proliferation, migration, differentiation, and integrated morphogenetic interactions, and therefore it is extremely vulnerable to developmental defects that cause congenital heart diseases (CHD). One of the major causes of CHD has been shown to be the mutations in key cardiac channel-forming proteins namely, connexins (Cxs). Cxs are tetra-spanning transmembrane proteins that form gap junction channels and hemichannels on cellular membrane. They allow passage of small molecules or ions between adjacent cells or between cells and the extracellular environment. Studies have revealed that the spatiotemporal expression of Cxs mainly, Cx31.9, Cx40, Cx43, and Cx45 is essentially involved in early developmental events, morphogenetic transformations, maturation, and functional significance of heart. Our lab and others have shown that mutations in gap junction proteins could result in impaired trafficking, misfolding, and improper ...
This abstract was presented at the 2014 FASEB Summer Research Conference in Saxtons River, Vermont by J. Scott Lauritzen, Crystal L. Sigulinsky, Noah T. Nelson, Nathan R. Sherbotie, Danny P. Emrich, Rebecca L. Pfeiffer, Jefferson R. Brown, John V. Hoang, Joshua M. Dudleston, Carl B. Watt, Kevin Rapp, Marguerite V. Shaw, Jia-Hui Yang, James R. Anderson, Bryan W. Jones and Robert E. Marc.. Purpose: Functional mapping in tiger salamander shows that bipolar cell (BC) projective fields far exceed their axonal fields, and directly implicates wide-field GABAergic amacrine cells (wf γACs) and gap junctions (Asari & Meister, 2014). Strikingly, single BCs exert differential effects on functionally distinct ganglion cells (GCs), likely achieved by privatized amacrine cell (AC) presynaptic inhibition to specific BC-GC synaptic pairs (Asari & Meister, 2012). To address whether BC projective fields in the mammal are equally broad, wf γAC- and gap junction-dependent, and GC type unselective, we reconstructed ...
Connexins are tetraspan transmembrane proteins that form gap junctions and facilitate direct intercellular communication, a critical feature for the development, function, and homeostasis of tissues and organs. In addition, a growing number of gap junction-independent functions are being ascribed to these proteins. The connexin gene family is under extensive regulation at the transcriptional and post-transcriptional level, and undergoes numerous modifications at the protein level, including phosphorylation, which ultimately affects their trafficking, stability, and function. Here, we summarize these key regulatory events, with emphasis on how these affect connexin multifunctionality in health and disease ...
Discussion. This study presents for the first time that gap junctions in the fiber cells of embryonic chicken lenses contain different amounts of cholesterol as determined by filipin cytochemistry and freeze-fracture TEM. For the purpose of determining their heterogeneous distributions in different cortical regions of the lens, we have classified these cholesterol-containing gap junctions as three subtypes based on the number of filipin-cholesterol complexes (FCCs) per unit area (i.e., μm2) of gap junction plaques. Namely, cholesterol-poor and -free subtypes contain 0-50 FCCs/μm2 Gj area, cholesterol-intermediate subtypes contain 51-100 FCCs/μm2 Gj area, and cholesterol-rich subtypes contain 101-300 FCCs/μm2 Gj area. By using the same technique, the presence of cholesterol-free gap junctions has previously been found in the aging human lens [25]. In addition, in view of the presence of the similar aquaporin junctions which contain aquaporin 0 [27] in lens fiber cells, the nature of these ...
This gene is a member of the connexin gene family. The encoded protein is a component of gap junctions, which are composed of arrays of intercellular channels that provide a route for the diffusion of low molecular weight materials from cell to cell. Mutations in this gene may be associated with atrial fibrillation. Alternatively spliced transcript variants encoding the same isoform have been described. [provided by RefSeq, Jul 2008 ...
During the assembly of gap junctions, a hemichannel in the plasma membrane of one cell is thought to align and dock with another in an apposed membrane to form a cell-to-cell channel. We report here on the existence and properties of nonjunctional, plasma membrane connexin43 (Cx43) hemichannels. The opening of the hemichannels was demonstrated by the cellular uptake of 5(6)-carboxyfluorescein from the culture medium when extracellular calcium levels were reduced. Dye uptake exhibited properties similar to those of gap junction channels. For example, using different dyes, the levels of uptake were correlated with molecular size: 5(6)-carboxyfluorescein (approximately 32%), 7-hydroxycoumarin-3-carboxylic acid (approximately 24%), fura-2 (approximately 11%), and fluorescein-dextran (approximately 0.4%). Octanol and heptanol also reduced dye uptake by approximately 50%. Detailed analysis of one clone of Novikoff cells transfected with a Cx43 antisense expression vector revealed a reduction in dye ...
Purpose: : Oculodentodigital dysplasia (ODDD) is characterized by ocular abnormalities including microphthalmia, enophthalmia, iris malformation and microcornea. A recent clinical report (Gabriel et al, 2011. Arch Ophthalmol 129: 781) examined two ODDD patients and found optic nerve and retinal aberrations not emphasized previously. Also, ciliary body cysts in one patient had not been associated with human ODDD previously. Gja1Jrt/+ mice, a mimic of human ODDD, have ciliary body cysts and retinal abnormalities (Tsui et al. IOVS 52:3539). Gja1Jrt/+ mice carry a glycine to serine substitution at position 60 (G60S) in connexin43, the product of the gap junction alpha 1 (Gja1) gene. Connexins form gap junctions between cells in multiple structures of the eye: ciliary body, lens, iris and retina. The purpose of this project was to show the high prevalence of retinal aberrations in older ODDD mice and the correlation between anterior segment phenotype and the mutant domain of the protein. Methods: : ...
Gap junctions (GJs) are intercellular channels connecting the cytoplasm of adjacent cells. This type of connection is an efficient way of cellular communications in many tissues including the central nervous system. Connexins are the proteins that constitute mammalian GJs, and Connexin43 (Cx43) is the most abundant isoform expressed in body cells. Cx43 has been detected within immature neural populations, but only in astrocytes in the adult brain and investigations have shown that Cx43 channel and adhesive properties largely influence neuronal differentiation of mouse neural progenitor (NP) cells. To date the role of Cx43 in neuronal differentiation remains unexplored in human systems, hence our study aimed to investigate the Cx43 participation in human NP differentiation. We largely detected Cx43 protein within the immature neural populations showing that protein expression occurred by fibroblast growth factor (FGF _2) stimulation through the ERKlj2 pathway; FGF _2 withdrawal induced NP ...
NIH 1RO1-GM098584-01A1, for Structure-function Relation of Connexin Disease Mutations. Principal investigator. Sept. 1, 2012 - Aug. 31, 2016; $109,468 per year. In this grant I investigate structural alterations in the N-termini of Connexin gap junction molecules in diseases such as deafness, fatal skin disease and neuropathy. I use NMR spectroscopy to produce structural data of these molecules, which are then analyzed with functional data showing alterations in gap junctions observed in these diseases. The structural and functional data may provide insight into the etiology of these diseases as well as molecular mechanistic information on gap junction assembly and gating. (Grants and Fellowships) ...
During the last decades it became increasingly evident that electrical synapses are capable of activity-dependent plasticity. However, measuring the actual strength of electrical transmission remains difficult. Usually changes in coupling strength can only be inferred indirectly from measures such as the coupling coefficient and the coupling conductance. Because these are affected by both junctional and non-junctional conductance, plastic changes can potentially be due to both components. Furthermore, these techniques also require the blocking of chemical transmission, so that processes that involve crosstalk between chemical and electrical synapses will be suppressed. To directly examine the magnitude of errors that can occur, we use dual whole-cell current- and voltage-clamp recordings from the soma of the pair of easily accessible, electrically coupled Retzius cells in the leech to simultaneously determine coupling coefficients, coupling conductances and directly measured gap junctional ...
Cx43, a major cardiac connexin, forms precursor hemichannels that accrue at the intercalated disc to assemble as gap junctions. While gap junctions are crucial for electrical conduction in the heart, little is known about the potential roles of hemichannels. Recent evidence suggests that inhibiting Cx43 hemichannel opening with Gap19 has antiarrhythmic effects. Here, we used multiple electrophysiology, imaging, and super-resolution techniques to understand and define the conditions underlying Cx43 hemichannel activation in ventricular cardiomyocytes, their contribution to diastolic Ca2+ release from the sarcoplasmic reticulum, and their impact on electrical stability. We showed that Cx43 hemichannels were activated during diastolic Ca2+ release in single ventricular cardiomyocytes and cardiomyocyte cell pairs from mice and pigs. This activation involved Cx43 hemichannel Ca2+ entry and coupling to Ca2+ release microdomains at the intercalated disc, resulting in enhanced Ca2+ dynamics. Hemichannel ...
SKKUs research team led by Prof. Jong Sun KANG of the Dept. of Medicine demonstrated a role of a cell surface receptor Cdon in preventing cardiac remodeling through suppression of Wnt signaling. Cdon is expressed and predominantly localized at intercalated disk in both mice and human hearts. Cdon−/− mice develop cardiac dysfunction and fibrosis with altered expression of remodeling genes. Cdon deficiency causes aberrant localization and function of gap junction protein connexin 43, correlating with hyperactivated Wnt signaling. Blocking of Wnt signaling in Cdon-depleted cardiomyocytes attenuates aberrant intercellular coupling. Conversely, Wnt activator causes aberrant activation of gap junction with decreased Cdon levels, suggestive of a feedback mechanism. This data suggests that Cdon is required for the control of Wnt signaling to prevent cardiac remodeling.. The research, supported by the Ministry of Science, ICT and Future Planning, as a part of a project supporting the cultivation of ...
Background Gap junction communication has been shown in glial and neuronal cells and it is thought they mediate inter- and intra-cellular communication. Connexin 36 (Cx36) is expressed extensively in the developing brain, with levels peaking at P14 after which its levels fall and its expression becomes entirely neuronal. These and other data have led to the hypothesis that Cx36 may direct neuronal coupling and neurogenesis during development. Methodology/Principal Findings To investigate Cx36 function we used a neurosphere model of neuronal cell development and developed lentiviral Cx36 knockdown and overexpression strategies. Cx36 knockdown was confirmed by western blotting, immunocytochemistry and functionally by fluorescence recovery after photobleaching (FRAP). We found that knockdown of Cx36 in neurosphere neuronal precursors significantly reduced neuronal coupling and the number of differentiated neurons. Correspondingly, the lentiviral mediated overexpression of Cx36 significantly increased the
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Pannexin2 (Panx2) is the largest of three members of the pannexin proteins. Pannexins are topologically related to connexins and innexins, but serve different functional roles than forming gap junctions. We previously showed that pannexins form oligomeric channels but unlike connexins and innexins, they form only single membrane channels. High levels of Panx2 mRNA and protein in the Central Nervous System (CNS) have been documented. Whereas Pannexin1 (Panx1) is fairly ubiquitous and Pannexin3 (Panx3) is found in skin and connective tissue, both are fully glycosylated, traffic to the plasma membrane and have functions correlated with extracellular ATP release. Here, we describe trafficking and subcellular localizations of exogenous Panx2 and Panx1 protein expression in MDCK, HeLa, and HEK 293T cells as well as endogenous Panx1 and Panx2 patterns in the CNS. Panx2 was found in intracellular localizations, was partially N-glycosylated, and localizations were non-overlapping with Panx1. Confocal images of
Pannexin1 (Panx1) forms nonselective membrane channels, structurally similar to gap junction hemichannels, that is permeable to ions, nucleotides and other small molecules below 900 Da. Panx1 activity is implicated in paracrine signaling and inflammasome regulation. Recent studies in different animal models showed that Panx1 overactivation correlates with a selective demise of several types of neurons, including retinal ganglion cells, brain pyramidal and enteric neurons. The list of Panx1 activators includes extracellular ATP, glutamate, high K+, Zn2+, fibroblast growth factors (FGFs), pro-inflammatory cytokines and elevation of intracellular Ca2+. Most of these molecules are released following mechanical, ischemic or inflammatory injury of the CNS, and rapidly activate this channel. As a result, prolonged opening of Panx1 channel induced by these
Buy anti-cx35 antibody, Mouse Connexin 35 Monoclonal Antibody (Clone 2Q2144)-NP_919401.1 (MBS603567) product datasheet at MyBioSource, Primary Antibodies. Application: Immunohistochemistry (IHC)
Intercellular gap-junctional communication (GJC) plays an important role in ovarian cell physiology. Closure of GJC has been proposed to be involved in oocyte maturation, particularly in the resumption of meiosis, both in vivo and in vitro, by controlling the flow of meiosis inhibitors, such as cAMP and cGMP. Understanding how GJC dynamics are regulated during in vitro maturation (IVM) could provide a powerful tool for controlling meiotic resumption and oocyte maturation in vitro. Since little is known about the GJC dynamic regulation between cumulus cells, we have developed an assay based on recovery of calcein fluorescence in photobleached cumulus cells, a gap-FRAP assay. The GJC profile has been characterized during the first hours of porcine IVM. We showed that equine chorionic gonadotropin (eCG) and epidermal growth factor (EGF) down-regulated GJC effectiveness between cumulus cells. However, human chorionic gonadotropin was not down-regulating GJC effectiveness. We also showed that the GJC ...
One embodiment includes a capacitor case sealed to retain electrolyte, at least one electrode disposed in the capacitor case, the at least one electrode comprising an overcurrent protector, a conductor coupled to the overcurrent protector and in electrical communication with a remainder of the electrode, the conductor sealingly extending through the capacitor case to a terminal disposed on an exterior of the capacitor case, a second electrode disposed in the capacitor case, a separator disposed between the electrode and the second electrode and a second terminal disposed on the exterior of the capacitor case and in electrical communication with the second electrode, with the terminal and the second terminal electrically isolated from one another, wherein the overcurrent protector is to interrupt electrical communication between the terminal and the remainder of the electrode at a selected current level.
The spontaneous firing of auditory neurons triggered by the release of the neurotransmitter glutamate from the inner hair cells (IHCs) of the cochlea is critical for neuronal survival during development of the auditory system. However, how these responses are triggered before the auditory canal has opened (that is, without sound as a stimulus) is unknown. Tritsch et al. removed cochlea from postnatal rats with closed auditory canals, performed whole-cell voltage clamp experiments, and measured low-frequency spontaneous currents and extracellular potentials in the supporting cells of a structure called Köllikers organ, which resides close to the IHCs. Antagonists of the P2 purinergic receptors P2Y and P2X inhibited these spontaneous potentials, as did the ATP-hydrolyzing enzyme, apyrase. The supporting cells contain connexin 26 and are connected to each other by gap junctions, and ATP-dependent spontaneous potentials were blocked by gap junction inhibitors. The authors then simultaneously ...
After repeated seizures, the expression levels of Cx32, Cx43, and Cx36 mRNAs at the epileptic foci were increased significantly. Blockade of the gap junctions with carbenoxolone shortened the duration of seizures and decreased the amplitude of the seizure discharges, whereas their opening with trime …
Autori: Iacobas DA, Suadicani SO, Iacobas S, Chrisman C, Cohen M, Spray DC, Scemes E. Editorial: J Membr Biol, 217(1-3), p.83-91, 2007.. Rezumat:. Gap junctions and purinergic P2 receptors (P2Rs) can be regarded as belonging to a common functional unit, given that they are involved in the transmission of calcium signals between cells. We have previously shown that deletion of the Gja1 gene alters expression levels of numerous genes encoding proteins with diverse functions, including purinergic receptors (P2Rs), and have found that genes synergistically or antagonistically expressed in wild-type tissues are more prone to be similarly or oppositely regulated in Cx43-nulls. We have now explored the use of coordination analysis of gene expression as a strategy to identify interlinked genes encoding functionally related proteins and pull-downs to evaluate their interlinkage. Our findings indicate that, in brain and in cultured astrocytes, several of these coexpressed genes encode proteins that are ...
Connexins (Cxs) are encoded by a large gene family predicted to include at least 20 isoforms in humans. Most mammalian Cx genes consist of two exons. The first consists of untranslated sequence, and the second contains the entire coding sequence. Exceptionally, Cx36 and Cx45 contain 3 exons and 2 introns and the third exon contains the coding sequence (Belluardo et al. 1999 ; Jacob and Beyer 2001). Connexins have been divided in two major subgroups, alpha and beta, according to their amino acid sequence similarity (see Bruzzone et al., 2001; Willecke et al., 2002). Alternative names and additional subgroups have been suggested as well. Cx are synthesized by ribosomes in the endoplasmic reticulum (ER) membrane. All Cx proteins contain four trans-membrane domains (TM1 to TM4), two extracellular loops (E1 and E2) and one cytoplasmic loop. The amino- and carboxyl termini are located in the cytosol (reviewed in Segretain and Falk, 2004). After targeting to the ER, connexins are checked by a quality ...
Connexins (Cxs) are encoded by a large gene family predicted to include at least 20 isoforms in humans. Most mammalian Cx genes consist of two exons. The first consists of untranslated sequence, and the second contains the entire coding sequence. Exceptionally, Cx36 and Cx45 contain 3 exons and 2 introns and the third exon contains the coding sequence (Belluardo et al. 1999 ; Jacob and Beyer 2001). Connexins have been divided in two major subgroups, alpha and beta, according to their amino acid sequence similarity (see Bruzzone et al., 2001; Willecke et al., 2002). Alternative names and additional subgroups have been suggested as well. Cx are synthesized by ribosomes in the endoplasmic reticulum (ER) membrane. All Cx proteins contain four trans-membrane domains (TM1 to TM4), two extracellular loops (E1 and E2) and one cytoplasmic loop. The amino- and carboxyl termini are located in the cytosol (reviewed in Segretain and Falk, 2004). After targeting to the ER, connexins are checked by a quality ...
The membrane-permeabilizing action of ATP (formation of a transmembrane pathway for flux of moderately sized molecules) first described as mediated by the so-called purinergic P2Z receptor (20) was later identified as being due to P2X7R (33, 47). The physical relationship between the P2X7R cation channel and the nonselective pore was until very recently unclear. Several models for pore formation have been proposed to explain the somewhat variable degree of agonist-induced permeabilization among various cell types; these include the recruitment of monomeric channel subunits (12, 13, 48) and the recruitment of a lytic pore (34), which has been recently suggested to be Panx1 (30, 38).. Pannexins are a newly discovered (but phylogenetically old) group of proteins that share no sequence homology with the vertebrate gap junction proteins, connexins, and a low but significant homology with the nonchordate gap junction proteins, the innexins (5, 35, 36, 52). When expressed in Xenopus oocytes, Panx1 and ...
Electrical synapses are formed by gap junctions that allow molecules to directly pass between neurons, creating a cytoplasm-to- ... Goodenough, Daniel A. (2009). "Gap junctions". Cold Spring Harbor Perspectives in Biology. 1:a002576 (1): a002576. doi:10.1101/ ...
Gap junctions allow the action potential to be transferred from one cell to the next (they are said to electrically couple ... All cardiac muscle cells are electrically linked to one another, by structures known as gap junctions (see below) which allow ... Kurtenbach S, Kurtenbach S, Zoidl G (2014). "Gap junction modulation and its implications for heart function". Frontiers in ... ISBN 978-0-912912-11-0. Goodenough, Daniel A.; Paul, David L. (2009-07-01). "Gap junctions". Cold Spring Harbor Perspectives in ...
"Entrez Gene: GJA4 gap junction protein, alpha 4, 37kDa". Winterhager E, Kidder GM (May 2015). Gap junction connexins in female ... Gap junction alpha-4 protein, also known as Connexin-37 or Cx37, is a protein that in humans is encoded by the GJA4 gene. This ... Van Camp G, Coucke P, Speleman F, Van Roy N, Beyer EC, Oostra BA, Willems PJ (November 1995). "The gene for human gap junction ... ISBN 978-1-934115-46-6. Beyer EC, Paul DL, Goodenough DA (July 1990). "Connexin family of gap junction proteins". The Journal ...
The epithelial-cell gap-junction network couples non-sensory epithelial cells, while the connective-tissue gap-junction network ... Gap-junction channels recycle potassium ions back to the endolymph after mechanotransduction in hair cells. Importantly, gap ... Gap-junction proteins, called connexins, expressed in the cochlea play an important role in auditory functioning. Mutations in ... Kikuchi, T.; Kimura, R. S.; Paul, D. L.; Takasaka, T.; Adams, J. C. (2000). "Gap junction systems in the mammalian cochlea". ...
Due to the direct connection between excitable cells in the form of gap junctions, an action potential can be transmitted ... Brink PR, Cronin K, Ramanan SV (August 1996). "Gap junctions in excitable cells". Journal of Bioenergetics and Biomembranes. 28 ... A special case of a chemical synapse is the neuromuscular junction, in which the axon of a motor neuron terminates on a muscle ... Muscle action potentials are provoked by the arrival of a pre-synaptic neuronal action potential at the neuromuscular junction ...
Gap junctions synchronize cell activation. The body of the cell between the processes first deposits enamel, which will become ...
Some research has found that when gap junction genes were transfected into tumor cells that did not have the gap junction genes ... Animal cells contain gap junctions and can communicate through these junctions in a process called cell-cell recognition. Plant ... Stem cells and tumor-causing cells, however, do not have gap junctions so they cannot be affected in the way that one would ... This stability leads researchers to believe that gap junctions will be a part of cancer treatment in the future. cells will ...
For the last 20 years before Warner began her research on gap junctions, embryologists had been working hard to prove that gap ... Warner, Anne (1992). "Gap junctions in development--a perspective". Semin. Cell Biol. 3 (1): 81-91. doi:10.1016/S1043-4682(10) ... After confirming the successful blocking of the gap junctions in the 8-cell-embryos, Warner continued to grow the embryos and ... After injecting the embryos with a specific antibody, which was said to have blocked the channels of gap junctions, Warner ...
Britz-Cunningham, S. H; Shah, M. M; Zuppan, C. W; Fletcher, W. H (1995). "Mutations of the Connexin43 gap-junction gene in ... Oviedo, N. J; Levin, M (2007). "Smedinx-11 is a planarian stem cell gap junction gene required for regeneration and homeostasis ... Bauer, R; Lehmann, C; Fuss, B; Eckardt, F; Hoch, M (2002). "The Drosophila gap junction channel gene innexin 2 controls foregut ... Levin, M; Mercola, M (1999). "Gap junction-mediated transfer of left-right patterning signals in the early chick blastoderm is ...
Gap junctions have been demonstrated in rare circumstances as one coupling mechanism between ICC and smooth muscle cells. ... Are gap junctions required for intercellular coupling?". Experientia. 46 (10): 1002-5. doi:10.1007/BF01940654. PMID 2226711. ... Electron microscopic and dye coupling studies to date have confirmed gap junctions as the major coupling mechanisms between ...
Gap junctions Desmosomes Adherens junctions Tight junctions Gap junctions bring the adjacent cells within 2 nanometers of each ... Bennett, M. V.; Barrio, L. C.; Bargiello, T. A.; Spray, D. C.; Hertzberg, E.; Sáez, J. C. (1 March 1991). "Gap junctions: new ... Desmosomes leave a gap of 30 nanometers between cells. Adherens junctions, also called zonula adherens, are multiprotein ... Similar to adherens junctions, the intracellular domains of tight junctions interact with different scaffold proteins, adapter ...
Gap junctions and edhf. Univ Wales Medicine July 2004: EP1435925 Gap junctions and EDHF. June 2003: US 20030105165 Gap ... and in particular on the role of gap junctions. He conducted research in three areas: endothelial control of arterial tone by ... junctions and endothelial-derived hyperpolarizing factor (edhf). University Of Wales College Of Medecine April 2003: WO 2003/ ...
Gap junctions are specialized channels located within the cell membrane of many animal cell types, which serve as gateways that ... Witkop Jr, C. J.; White, J. G.; Waring, G. O. (1982). "Hereditary mucoepithelial dysplasia, a disease of gap junction and ... Lampe, P.; Lau, A. F. (Dec 2000). "Regulation of gap junctions by phosphorylation of connexins". Archives of Biochemistry and ... The disorder is attributed to improper formation of desmosomes and gap junctions, which prevents proper cornification of the ...
The gap junctions also connect deeper layers of cells to the surface layer (osteocytes when surrounded by bone). This was ... The osteoblasts are also connected by gap junctions, small pores that connect osteoblasts, allowing the cells in one cohort to ... Doty SB (1981). "Morphological evidence of gap junctions between bone cells". Calcif. Tissue Int. 33 (5): 509-12. doi:10.1007/ ... Yellowley CE, Li Z, Zhou Z, Jacobs CR, Donahue HJ (February 2000). "Functional gap junctions between osteocytic and ...
... rather it gap junctions with adjacent astrocytes, providing secondary pathway to nearby oligodendrocytes. With direct gap ... 2009). "Impaired astrocytic gap junction coupling and potassium buffering in a mouse model of tuberous sclerosis complex." ... With impairment in gap junction coupling between astrocytes, myriad of abnormalities in potassium buffering occurs which ... The panglial syncytium is a large network of interconnected glial cells, which are extensively linked by gap junctions. The ...
Gap junction gamma-3, also known as connexin-29 (Cx29) or gap junction epsilon-1 (GJE1), is a protein that in humans is encoded ... This gene encodes a gap junction protein. The encoded protein is known as a connexin, most of which form gap junctions that ... "Entrez Gene: gap junction protein". Altevogt BM, Kleopa KA, Postma FR, Scherer SS, Paul DL (August 2002). "Connexin29 is ... Kleopa KA, Orthmann JL, Enriquez A, Paul DL, Scherer SS (September 2004). "Unique distributions of the gap junction proteins ...
Gap junction beta-5 protein (GJB5), also known as connexin-31.1 (Cx31.1), is a protein that in humans is encoded by the GJB5 ... Gap junctions are conduits that allow the direct cell-to-cell passage of small cytoplasmic molecules, including ions, metabolic ... Gap junction channels consist of connexin protein subunits, which are encoded by a multigene family. GRCh38: Ensembl release 89 ... "Entrez Gene: gap junction protein". Canova C, Hashibe M, Simonato L, et al. (2009). "Genetic associations of 115 polymorphisms ...
Gap junction delta-4 protein (GJD4), also known as connexin-40.1 (Cx40.1), is a protein that in humans is encoded by the GJD4 ... "Entrez Gene: gap junction protein". Söhl G, Nielsen PA, Eiberger J, Willecke K (2003). "Expression profiles of the novel human ... Each gap junction channel is formed by docking of 2 hemichannels, each of which contains 6 connexin subunits. GRCh38: Ensembl ... Connexins, such as GJD4, are involved in the formation of gap junctions, intercellular conduits that directly connect the ...
Gap junction delta-2 (GJD2), also known as connexin-36 (Cx36) or gap junction alpha-9 (GJA9), is a protein that in humans is ... "Entrez Gene: gap junction protein". White TW, Srinivas M, Ripps H, et al. (2002). "Virtual cloning, functional expression, and ... This gene is a member of the large family of connexins that are required for the formation of gap junctions. Six connexin ... 2001). "Identification and functional expression of HCx31.9, a novel gap junction gene". Cell Commun. Adhes. 8 (4-6): 173-8. ...
Gap junction alpha-10 protein, also known as connexin-62 (Cx62), is a protein that in humans is encoded by the GJA10 gene. ... "Entrez Gene: gap junction protein". Söhl G, Nielsen PA, Eiberger J, Willecke K (2003). "Expression profiles of the novel human ... Each gap junction channel is formed by docking of 2 hemichannels, each of which contains 6 connexin subunits. ENSG00000288435 ... Connexins, such as GJA10, are involved in the formation of gap junctions, intercellular conduits that directly connect the ...
Gap junction gamma-2 (GJC2), also known as connexin-46.6 (Cx46.6) and connexin-47 (Cx47) and gap junction alpha-12 (GJA12), is ... This gene encodes a gap junction protein. Gap junction proteins are members of a large family of homologous connexins and ... "Entrez Gene: gap junction protein". Ostergaard P, Simpson MA, Brice G, et al. (2011). "Rapid identification of mutations in ... 2010). "Two novel gap junction protein alpha 12 gene mutations in two Chinese patients with Pelizaeus-Merzbacher-like disease ...
Gap junctions are critical for cardiac myocytes, mice and humans deficient in a particular gap junction protein have severe ... gap junctions in animals and plasmodesmas in plants. Gap junctions are made of connexins in vertebrates and innexins in ... Electrical synapses are electrically conductive gap junctions between neurons. ... A communicating junction links the intracellular compartments of two adjacent cells, allowing transit of relatively small ...
It has been demonstrated that miR-155 can be transferred through gap junctions from leukemic cells to healthy B cells and ... Nesmiyanov P, Strygin A, Tolkachev B, Kaplanov K, Dotsenko A, Strygina A (2016). "mIRNA-155 shuttling through gap junctions ...
These gap junctions are made of proteins called connexins. There are fewer gap junctions within the SA node and they are ... Action potentials pass from one cardiac cell to the next through pores known as gap junctions. ...
This fluid contains substances too large to be transported through the gap junctions that connect the osteocytes. In cartilage ... These cytoplasmic processes are joined together by gap junctions. Osteocytes do not entirely fill up the canaliculi. The ...
1861-1968 Taylor Gap, Taylor's Gap, Bowman's Forest East, Bowman Gap) • Bowser (1920-1968 Beechworth Junction) • Byawatha • ... Halls Gap (Borough Huts, Grampians Junction) • Illawarra (1910-1965) • Joel Joel • Joel South (1916-1965) • Kanya (1891-1975 ... Nariel Gap, Nariel Junction, Hodgsons Crossing, Mcnamara Crossing, The Lightwood, Willow Crossing) • Old Tallangatta (1871-1955 ... Buckland Junction, Salt Log, Upper Buckland, Upper Buckland Junction) • Buffalo River (1887-1919) • Coral Bank (1918-1968) • ...
Intercellular gap junctions in vertebrates, including humans, are formed by the connexin family of proteins. Structurally, ... Panchin Y, Kelmanson I, Matz M, Lukyanov K, Usman N, Lukyanov S (June 2000). "A ubiquitous family of putative gap junction ... While innexins are responsible for forming gap junctions in invertebrates, the pannexins have been shown to predominantly exist ... Shestopalov VI, Panchin Y (February 2008). "Pannexins and gap junction protein diversity". Cellular and Molecular Life Sciences ...
Ren, Y; Carretero, O; Garvin, J (2002). "Role of mesangial cells and gap junctions in tubuloglomerular feedback". Kidney ... Extraglomerular mesangial cells are in close connection to afferent and efferent arteriolar cells by gap junctions, allowing ... Communication between mesangial cells and vascular smooth muscle cells via gap junctions helps regulate the process of ...
The mutation can appear in GJB1 coding for connexin 32, a gap junction protein expressed in Schwann cells. Because this protein ... Kleopa, Kleopas; Lupski, James R. (December 2011). "The Role of Gap Junctions in Charcot-Marie-Tooth Disease". Journal of ... Schwann cells and neurons exchange molecular signals by gap junctions that regulate survival and differentiation. Demyelinating ... mutated connexons create non-functional gap junctions that interrupt molecular exchange and signal transport. ...
"Entrez Gene: GJB6 gap junction protein, beta 6". Zhao HB, Kikuchi T, Ngezahayo A, White TW (2006). "Gap junctions and cochlear ... Gap junction channels are only found between cochlear supporting cells. While gap junctions in the inner ear are critically ... Connexin 30 (Cx30) is one of several gap junction proteins expressed in the inner ear. Mutations in gap junction genes have ... the epithelial cell gap junction network, which couple non-sensory epithelial cells, and the connective tissue gap junction ...
However, the leaf may be dissected to form lobes, but the gaps between lobes do not reach to the main vein. A compound leaf has ... Veins successively branching into equally sized veins from a common point, forming a Y junction, fanning out. Amongst temperate ...
Junction forward voltage V @ 25 °C Electron mobility m2/(V·s) @ 25 °C Hole mobility m2/(V·s) @ 25 °C Max.. junction temp.. °C ... the emitter-base junction is forward biased (electrons and holes recombine at the junction), and the base-collector junction is ... This construction produces two p-n junctions: a base-emitter junction and a base-collector junction, separated by a thin region ... The junction forward voltage is the voltage applied to the emitter-base junction of a BJT to make the base conduct a specified ...
Tunica intima:最內層是與血管長軸平行排列的內皮細胞(endothelium),細胞之間以tight junction(zonula adherens)和gap junction(nexus)相接,前者構成穿越障礙,後者
Next to the Royal Portbury Dock, off junction 19 of the M5 on the A369 is Lafarge Plasterboard. Thatchers Cider is in Sandford ... in the Avon Gap in the Wansdyke) in 652,[54] and further south at the Battle of Peonnum (at Penselwood) in 658,[55] followed by ... Centrax make industrial gas turbines in Newton Abbot; to the north-west, on the A38 at the A382 junction at Heathfield in Bovey ... Moog Controls UK, on the Ashchurch Ind Estate by Ashchurch for Tewkesbury near junction 9 (A46) of the M5, make servo valves ...
Gap junction Proteins. *G protein coupled receptors (e.g., Beta-adrenergic receptor) ...
Today we know that this type of electrical interaction is mediated by gap junctions. This idea, that electrical synapses couple ... One reason for his move to UCSD was that he hoped to bridge the gap between Marine Biology and medicine. ...
cell junction. • dendrite. • sarcolemma. • cell projection. • perikaryon. • synapse. • postsynaptic membrane. Biological ...
動物也有類似的構造,允許動物細胞間的物質交流,包含間隙連接(gap junctions)[7]和膜奈米管
It is on the Durango-Grand Junction Outrider line.[17] Major highways. *. State Highway 145 is part of the San Juan Skyway. It ... Harvey Gap. *Highline Lake. *Jackson Lake. *James M. Robb - Colorado River. *John Martin Reservoir ...
While rehearsing for the match off-air, he suggested a nearby cameraman look as well.[34] "There's gaps, you know, in parts of ... A headstone at the junction of Middlewood Road, Leppings Lane and Wadsley Lane, near the ground and by the Sheffield Supertram ...
Downregulation of RhoA in the HBE cell lines using siRNAs showed a lack of apical junction formation in contrast with the ... In fact, Ral-dependent branching implicated the phosphorylation of growth-associated protein GAP-43. Finally, Ral mutants ... In 2010, Hall analysed a number of Rho signalling pathways, which regulate the formation of apical junctions in human bronchial ... Further analysis showed that PRK2, a direct target of Rho, is required for the formation of apical junctions. Mutational ...
Elektrisk synapse/Gap junction. *Kemisk synapse *Synaptisk vesikel. *Zona activa. *Postsynaptisk densitet ...
In 1930, the railroad was abandoned, apart from a portion from Kirk to Fantail Junction, which was converted to standard gauge ...
The cleft contains gap junctions, tight junctions, desmosomes, and adheren proteins, all of which help to propagate and/or ... An intercellular cleft is a channel between two cells through which molecules may travel and gap junctions and tight junctions ... These tight junctions localize to the luminal side of the intercellular clefts, where the glycocalyx, which is important in ... Endothelial tight junctions are most commonly found in the intercellular cleft and provide for regulation of diffusion through ...
It is more likely that K+ ions and gap junctions can be involved in EDHF-mediated relaxation simultaneously, and may also act ... An alternative explanation for the EDHF phenomenon is that direct intercellular communication via gap junctions allows passive ... do gap junctions provide a unifying hypothesis?". British Journal of Pharmacology. 141 (6): 881-903. doi:10.1038/sj.bjp.0705698 ...
A close-up view of Kramer Junction SEGS plant. Trough systems predominate among today's commercial solar power plants. Nine ...
A triple-junction cell, for example, may consist of the semiconductors: GaAs, Ge, and GaInP. 2.[64] Triple-junction GaAs solar ... Semiconductors with band gap between 1 and 1.5eV, or near-infrared light, have the greatest potential to form an efficient ... Main article: Multi-junction solar cell. Multi-junction cells consist of multiple thin films, each essentially a solar cell ... Vadim Lashkaryov discovered p-n-junctions in Cu. 2. {\displaystyle _{2}}. O and silver sulphide protocells in 1941.. [7]. ...
The fossil record appears to show that the rate of extinction is slowing down, with both the gaps between mass extinctions ... Ideally the "family tree" has only two branches leading from each node ("junction"), but sometimes there is too little ... information to achieve this and paleontologists have to make do with junctions that have several branches. The cladistic ...
G. Shen, Y. Bando, D. Golberg : «InP-GaP Bi-Coaxial Nanowires and Amorphous GaP Nanotubes» JOURNAL OF PHYSICAL CHEMISTRY C 111[ ... J. A. RodrÃguez-Manzo, M. Wang, F. Banhart, Y. Bando and D. Golberg : «Multibranched Junctions of Carbon Nanotubes via Cobalt ... B. D. Liu, Y. Bando, C. C. Tang, D. Golberg, R. G. Xie and T. Sekiguchi : «Synthesis and optical study of crystalline GaP ... J. Zhan, Y. Bando, J. Hu, D. Golberg and K. Kurashima : «Fabrication of ZnO Nanoplate-Nanorod Junctions» Small 2[1] (2006) 62- ...
From 1941 onwards all military and many civil Tiger Moths were outfitted with anti-spin strakes positioned on the junction ... Four-seat cabin biplane, modified from existing DH.82A airframes by widening the gap between the fuselage longerons. 19 were ...
Electrical synapse/Gap junction. *Chemical synapse *Synaptic vesicle. *Active zone. *Postsynaptic density ...
These genes are often turned on or off by signal transduction, although in some systems where syncytia or gap junctions are ... Hall BK (15 January 2004). "In search of evolutionary developmental mechanisms: the 30-year gap between 1944 and 1974". 302. ... "stop-gap", good enough for short-term adaptation that allows the lineage to survive for long enough for mutation and/or ...
Deccan Traps at K/T junction; Siberian Traps at P-T junction); and other less dramatic processes.[14][15] ... It bridged the gap between different types of biologists: geneticists, naturalists, and palaeontologists. ... Causes include meteorite strikes (K-T junction; End-Ordovician extinction events); flood basalt provinces ( ...
... such as DNA Holliday junctions, DNA hairpins, or entire nucleosomes and chromatin. By acting upon the magnetic bead with the ... roughly exponentially with the distance from the axis linking the two magnets on a typical scale of about the width of the gap ...
The shielding had a gap on the underside. It is thought that no human has been seriously harmed by the escaping radiation.[116] ... 23 July 1964: Wood River Junction criticality accident. Resulted in 1 fatality ...
Circuits utilizing the properties of Si-SiGe junctions can be much faster than those using silicon alone.[68] Silicon-germanium ... including one that would fill a gap in the carbon family in his Periodic Table of the Elements, located between silicon and tin ... it can effectively shunt out a p-n junction. This is one of the primary reasons for the failure of old germanium diodes and ... The Mars Exploration Rovers and several satellites use triple junction gallium arsenide on germanium cells.[70] ...
In 1876, a branch line of the Central Pacific Railroad, the Berkeley Branch Railroad, was laid from a junction with the ... A gap in the middle allows passage by bikes and emergency vehicles. ...
Harvey Gap. *Highline Lake. *Jackson Lake. *James M. Robb - Colorado River. *John Martin Reservoir ...
After its junction with the Tuivai, the Barak River turns north, forms the border with Assam State, and then enters the Cachar ... There were times when the country was in turmoil without rulers and long historical gaps in between 1129 BCE and 44 BCE. In ...
The current Google Earth view (as at April 2012) shows waste ground, the Mission Hall, and one derelict farm building with gaps ... The junction is today known as Hatton Cross.. As London Heathrow Airport has grown, its eastern estates including car parks and ... unnamed gaps between aircraft-maintenance/service buildings, the south part of Eastchurch Road, and a southern stump. ...
... "gap junction" and "gap junction plaque" non-interchangeable.[116] In other words, the commonly used term "gap junction" always ... "gap junction" and "gap junction plaque" non-interchangeable as the area of the gap junction plaque may contain proteins other ... A gap junction may also be called a nexus or macula communicans. While an ephapse has some similarities to a gap junction, by ... Gap junctions were so named because of the "gap" shown to be present at these special junctions between two cells.[90] With the ...
Gap junctions are abundant in epithelial tissues and cardiac muscle [1]. ... gap junction (*nexus*)* A passage through the lipid bilayers of adjacent plasma membranes that mediates the transfer of small ... gap junction A communicating junction between cells, which provides a rapid passage for ions and small molecules such that they ... Gap junctions, together with chemical synapses (which function through neurotransmitters), are communicating junctions and ...
A current model of the gap junction consists of a cluster of gap-junction channels. Both membranes contain connexon ... Protein component of gap junctions which are specialized regions of the plasma membrane formed by a cluster of channels ...
Tag: gap junctions. Posted on May 6, 2013. January 3, 2016. Sparse Network Principles of GABAergic Amacrine Cell Heterocellular ...
... evidence that gap junctions can contribute to epileptogenesis in the hippocampus and cortex-but not just any gap junctions. ... evidence that gap junctions can contribute to epileptogenesis in the hippocampus and cortex-but not just any gap junctions. ... Gap junction effects on precision and frequency of a model pacemaker network. J Neurophysiol 2000; 83: 984-97.PubMedGoogle ... Gap junctions synchronize the firing of inhibitory interneurons in guinea pig hippocampus. Brain Res 2001; 907: 139-143.PubMed ...
... including gap junctions. Gap junctions are found in cardiac and smooth muscle, where they function to increase the speed of... ... Skeletal muscle does not contain any type of cell-to-cell junctions, ... Skeletal muscle does not contain any type of cell-to-cell junctions, including gap junctions. Gap junctions are found in ... In addition to gap junctions, other types of junctions include anchoring junctions and desmosomes, which keep muscle cells ...
Gap junctions are cylindrical channels between animal cells that let molecules and ions pass from one cell to another. These ... Gap junctions are cylindrical channels between animal cells that allow small molecules and ions to pass from the inside of one ... Gap junctions only let ions, or charged particles, and small molecules up to about 1,000 daltons pass through into the next ... Gap junctions are essential to the bodys proper functioning due to their role in electrical coupling. As they allow charged ...
Gap junction proteins Gap junction α (GJA) proteins GJA1, gap junction alpha-1 protein GJA2, gap junction alpha-2 protein GJA3 ... gap junction beta-5 protein GJB6, gap junction beta-6 protein GJB7, gap junction beta-7 protein Gap junction γ (GJC) proteins ... gap junction alpha-3 protein GJA4, gap junction alpha-4 protein GJA5, gap junction alpha-5 protein GJA6, gap junction alpha-6 ... gap junction alpha-12 protein Gap junction β (GJB) proteins GJB1, gap junction beta-1 protein GJB2, gap junction beta-2 protein ...
Pannexins and gap junction protein diversity.. Shestopalov VI1, Panchin Y.. Author information. 1. Bascom Palmer Eye Institute, ... Gap junctions (GJs) are composed of proteins that form a channel connecting the cytoplasm of adjacent cells. Connexins were ...
Characterization of connexin36 gap junctions in the human outer retina.. Kántor O1, Benkő Z2,3, Énzsöly A4,5, Dávid C5, Naumann ... Retinal connexins (Cx) form gap junctions (GJ) in key circuits that transmit average or synchronize signals. Expression of Cx36 ...
InterPro provides functional analysis of proteins by classifying them into families and predicting domains and important sites. We combine protein signatures from a number of member databases into a single searchable resource, capitalising on their individual strengths to produce a powerful integrated database and diagnostic tool.
Minding the Gaps-and the Junctions, Too. Lawrence F. Brass, Timothy J. Stalker ... Gap junctions and connexin hemichannels underpin hemostasis and thrombosis. Circulation. 2012; 125: 2479-2491. ... Cx37 is a member of a family of gap junction proteins that can assemble a comparatively nonselective channel when cells come ... The tale of gaps and junctions between platelets is far from complete. ...
The gap junction communication channel.. Cell 84 381-8 1996. Kumar NM, Gilula NB. Molecular biology and genetics of gap ... Gap junction protein, cysteine-rich domain (IPR019570). Short name: Connexin_CCC Overlapping homologous superfamilies *Connexin ... Gap junctions in the brain: where, what type, how many and why?. Trends Neurosci. 16 186-92 1993 ... Vertebrate gap junction channels are thought to participate in diverse biological functions. For instance, in the heart they ...
One gap junction consists of a cluster of closely packed pairs of transmembrane channels, the connexons, through which ... gap junction SAAS annotation. ,p>Information which has been generated by the UniProtKB automatic annotation system, without ... Gap junction proteinUniRule annotation. ,p>Information which has been generated by the UniProtKB automatic annotation system, ... Gap junctionUniRule annotation. ,p>Information which has been generated by the UniProtKB automatic annotation system, without ...
Gap junction [ Pathway menu , Organism menu , Pathway entry , Download KGML , Show description , User data mapping ] Gap ... Communication through Gap Junction is sensitive to a variety of stimuli, including changes in the level of intracellular Ca2+, ... Each gap junction channel is formed by docking of two hemichannels, each containing six connexins, contributed by each ... Gap junctional communication is essential for many physiological events, including embryonic development, electrical coupling, ...
Gap junctions (GJs), intercellular channels composed of subunit connexins, can play a major role in secondary cell death by ...
Pannexins, a family of gap junction proteins expressed in brain. Roberto Bruzzone, Sheriar G. Hormuzdi, Michael T. Barbe, Anne ... Pannexins, a family of gap junction proteins expressed in brain. Roberto Bruzzone, Sheriar G. Hormuzdi, Michael T. Barbe, Anne ... Pannexins, a family of gap junction proteins expressed in brain. Roberto Bruzzone, Sheriar G. Hormuzdi, Michael T. Barbe, Anne ... A hallmark of gap-junction-forming proteins is the presence of conserved, regularly spaced cysteine residues located on the two ...
Gap junctions allow cytoplasmic molecules to move from one cell to another, and such communication appears to influence a broad ... Because loss of gap junction communication has been associated with carcinogenesis and enhanced EGF signaling also contributes ... Epidermal growth factor (EGF) is known to regulate conductance of gap junctions through mitogen-activated protein kinase- ... dependent phosphorylation of the connexin proteins that form gap junction channels. Leithe and Rivedal now present evidence ...
Gap junction channels allow communication in the form of small molecules that flow between adjacent cells. Conductance through ... The communication with the gap junction appeared to require PtdIns(4,5)P2 itself, rather than IP3 or DAG, and channel ... report that in Rat-1 fibroblasts, one way gap junction conductance can be regulated is through changes in the abundance of the ... Receptor-induced depletion of phosphatidylinositol 4,5-bisphosphate inhibits conductance of gap junction channels. ...
Purchase Gap Junctions: Molecular Basis of Cell Communication in Health and Disease, Volume 49 - 1st Edition. Print Book & E- ... Role of Gap Junctions in Cellular Growth Control and Neoplasia: Evidence and Mechanisms, R.J. Ruch. Gap Junctions in ... Invertebrate Gap Junctions: Gap Junction Communication in Invertebrates: The Innexin Gene Family, P. Phelan. ... Gap Junction Structure: New Structures and New Insights, G. Sosinsky. Degradation of Gap Junctions and Connnexins, J.G. Laing ...
Gap junctions act as low-pass filters. Left, An equivalent circuit of a gap junction. Right, Electrical signals pass through ... Dendrodendritic gap junctions between ganglion cells. A,B, Electron micrographs showing dendrodendritic gap junctions between ... Gap junctions and synchrony. One of the best described roles for gap junctions in the CNS is that they can synchronize activity ... Indeed, gap junction coupling of A8 amacrine cells, which are coupled to both ON and OFF bipolar cells with Cx36 gap junctions ...
Robust coding of flow-field parameters by axo-axonal gap junctions between fly visual interneurons. Hermann Cuntz, Juergen Haag ... With this study, we assign a specific computational function to gap junctions different from its commonly known role of ... Robust coding of flow-field parameters by axo-axonal gap junctions between fly visual interneurons ... Robust coding of flow-field parameters by axo-axonal gap junctions between fly visual interneurons ...
... Harissios ... Role of Gap Junctions in Transendothelial Migration," BioMed Research International, vol. 2014, Article ID 803257, 8 pages, ...
2002) Metabolic inhibition induces opening of unapposed connexin 43 gap junction hemichannels and reduces gap junctional ... As expected, blocking gap junctions/hemichannels with CBX (100 μm) reduced the ATP release induced by 0 mm Ca2+ (t 1/2 = 4.2 ... Gap junctions/hemichannels blocker MFA (100 μm) abolished 0 mm Ca2+ ACSF-induced Ca2+ transients. C1 , Profiles of spontaneous ... Gap junction blocker CBX totally abolished 0 mm Ca2+-induced ATP release. A2 , The remaining concentration of ATP in the ...
A point mutation in the gap-junction protein connexin 30 stops early onset age-related hearing loss. Here, the authors show ... The p.Ala88Val (A88V) mutation in the gene coding for the gap-junction protein connexin30 (Cx30) protects the cochlear basal ... suggesting that gap junctions contribute to passive cochlear mechanics and energy distribution in the active cochlea. ... that gap junctions contribute to cochlear micromechanics and that cochlear amplification is likely controlled by extracellular ...
The permeability of gap junctions to Lucifer Yellow depends upon the proteins that compose the gap junctions. Vertebrate gap ... The gap-junction resistance between one principal cell and the next is 431 kΩ, which is equivalent to a gap-junction ... The estimate is not unreasonable in view of as many as 10 000, the number of gap junctions per μm2 in a single gap junction ... Molecular evidence of gap junctions in insect Malpighian tubules. The molecular basis of gap junctions in invertebrates has ...
Compare gap junction protein, alpha 6 Biomolecules from leading suppliers on Biocompare. View specifications, prices, citations ... Gap Junction Protein, alpha 6 (GJA6) (AA 1-283) protein (His tag) ... Your search returned 5 gap junction protein, alpha 6 Biomolecules across 3 suppliers. ...
Rett Syndrome Astrocytes Are Abnormal and Spread MeCP2 Deficiency through Gap Junctions. Izumi Maezawa, Susan Swanberg, ... Rett Syndrome Astrocytes Are Abnormal and Spread MeCP2 Deficiency through Gap Junctions ... Rett Syndrome Astrocytes Are Abnormal and Spread MeCP2 Deficiency through Gap Junctions ... Rett Syndrome Astrocytes Are Abnormal and Spread MeCP2 Deficiency through Gap Junctions ...
Abstract 839: Transfer of siRNA Molecules via Gap Junctions in Heart Cells. Eddy Kizana, Eugenio Cingolani, Genaro Ramirez- ... To explore dependence of this effect on gap junctions, we co-transduced cells with a LV encoding a dominant-negative connexin43 ... This intercellular transfer is dependent on the presence of functional gap junctions and is capable of mediating knockdown of ... Repeat co-cultures revealed abrogation of GFP fluorescence and mRNA knockdown effect, confirming gap junction dependence. To ...
Gap Junction Channels. Some articles on gap, channel, junction, gap junction, gap junctions, channels:. List Of Airports By ... Gap Junction - Structure. ... In vertebrates, gap junction hemichannels are primarily homo- or hetero-hexamers of connexin ... Famous quotes containing the words channels, gap and/or junction:. "People between twenty and forty are not sympathetic. The ... Invertebrate gap junctions comprise proteins from the hypothetical innexin family ... the recently characterized pannexin ...
  • [8] Though differing in sequence to connexins, innexins are similar enough to connexins to state that innexins form gap junctions in vivo in the same way connexins do. (wikipedia.org)
  • They are characterized by the amount of connexins they contain, which are the protein families that make up junctions. (reference.com)
  • Retinal connexins (Cx) form gap junctions (GJ) in key circuits that transmit average or synchronize signals. (nih.gov)
  • The connexins are a family of integral membrane proteins that oligomerise to form intercellular channels that are clustered at gap junctions. (ebi.ac.uk)
  • Two connexons then interact (likely via the extracellular loops of their connexins) to form the complete gap junction channel. (ebi.ac.uk)
  • Each gap junction channel is formed by docking of two 'hemichannels', each containing six connexins, contributed by each neighboring cell. (genome.jp)
  • Gap junctions (GJs), intercellular channels composed of subunit connexins, can play a major role in secondary cell death by forming conduits through which toxic molecules from dying cells pass to and injure coupled neighbors. (jci.org)
  • Gap junctions are collections of intercellular channels that, in vertebrates, are formed by connexins, a multigene family of which 20 members have been identified in humans ( 1 ). (pnas.org)
  • Phosphorylation of Connexins: Consequences for Permeability, Conductance, and Kinetics of Gap Junction Channels, H.J. Jongsma, H.V.M. van Rijen, B.R. Kwak, and M. Chanson . (elsevier.com)
  • Connexins are the protein subunits forming the hexameric ring of a connexon, one half of a gap junction channel (GJC). (frontiersin.org)
  • Although this may seem to be a `housekeeping' function, several recent studies have revealed a surprising diversity in the permeability properties of gap junctions composed of different connexins. (biologists.org)
  • Objective: Gap junctions (formed by connexins, Cx) are important for functional coordination of cells in the vascular wall. (uni-muenchen.de)
  • While further study is needed to delineate the role of individual connexins, our data suggests that blockade of gap junctions may be a theraputic target in the treatment of retinal neovascular disease. (arvojournals.org)
  • The gap junctions (GJs) are hemichannels, called connexons, each formed by six connexins. (thefreedictionary.com)
  • Interactions of Connexins with Zona occludens proteins ( ZO-1 , ZO-2 and ZO-3 ) couple gap junction channels with the tight junction components, such as Occludin , and with cytoskeletal elements, such as Actin filaments [ 3 ]. (bio-rad.com)
  • Connexins 43 and 36 can anchor Microtubules (consisting of the Alpha/Beta-tubulin dimers) to gap junctions and thereby can affect the properties of microtubules in contacted cells [ 4 ], [ 5 ]. (bio-rad.com)
  • Analysis of gap junction assembly using mutated connexins detected in Charcot-Marie-Tooth X-linked disease. (wikipathways.org)
  • Membrane insertion of gap junction connexins: polytopic channel forming membrane proteins. (wikipathways.org)
  • Cell-free synthesis and assembly of connexins into functional gap junction membrane channels. (wikipathways.org)
  • Synthesis and assembly of connexins in vitro into homomeric and heteromeric functional gap junction hemichannels. (wikipathways.org)
  • Cxs (connexins), the protein subunits forming gap junction intercellular communication channels, are transported to the plasma membrane after oligomerizing into hexameric assemblies called connexin hemichannels (CxHcs) or connexons, which dock head-to-head with partner hexameric channels positioned on neighbouring cells. (portlandpress.com)
  • Gap junction (GJ) * proteins (termed connexins [Cxs]), comprise a family of vertebrate transmembrane proteins that assemble intracellularly to form oligomeric channels ( Musil and Goodenough, 1993 ). (rupress.org)
  • Connexins (Cxs) are transmembrane proteins that form channels which allow direct intercellular communication (IC) between neighbouring cells via gap junctions. (biochemsoctrans.org)
  • The possible implications of these findings on the regulation of native gap junctions that express both connexins remain to be determined. (ahajournals.org)
  • Loss of the gap junction protein connexin43 has been demonstrated in dysplastic cervix, but other connexins have not been investigated. (contemporaryobgyn.net)
  • Connexins, a family of 20 trans-membrane proteins in humans, comprise the main subunits of gap junctions - specialised clusters of intercellular channels that allow adjacent cells to directly share ions and hydrophilic molecules of up to ~1 KDa in size [1]. (contemporaryobgyn.net)
  • However, the tumour suppressive effects may be tissue and connexin-specific [11,12] and also appear to involve non-gap junctional properties of connexins [13-15]. (contemporaryobgyn.net)
  • Here, we used the dual whole-cell patch-clamp method to study the actions of 2-APB on gap junction channels formed by selected connexins expressed in a communication-deficient neuroblastoma cell line (N2A). (aspetjournals.org)
  • The differential efficacy of block by 2-APB of gap junction channels formed by different connexins may provide a useful tool that could be exploited in gap junction research to selectively block certain gap junction channel subtypes. (aspetjournals.org)
  • Double mutants and chimeras, which show that leo and luchs are only required in xanthophores and melanophores, but not in iridophores, suggest that both connexins form heteromeric gap junctions. (elifesciences.org)
  • suggest that heteromeric gap junctions formed from the connexins produced by leo and luchs are important for xanthophores and melanophores to communicate with each other and so form the stripy patterning seen on the body of the zebrafish. (elifesciences.org)
  • Gap junctions are composed of connexins and are critical for the maintenance of the differentiated state. (asm.org)
  • We have found that the restoration of density inhibition of human pancreatic cancer cells by the antiproliferative somatostatin receptor 2 (sst2) is due to overexpression of endogenous connexins Cx26 and Cx43 and consequent formation of functional gap junctions. (asm.org)
  • In contrast, the expression of communication-deficient gap junctions (containing mutated connexins) did not have this effect. (ku.edu)
  • One gap junction channel is composed of two protein heximers (or hemichannels) called connexons in vertebrates and innexons in invertebrates. (wikipedia.org)
  • In vertebrates , gap junction hemichannels are primarily homo- or hetero - hexamers of connexin proteins . (wikipedia.org)
  • Gap junction channels formed from two identical hemichannels are called homotypic, while those with differing hemichannels are heterotypic. (wikipedia.org)
  • Two hemichannels, joined together across a cell membrane comprise a Gap Junction channel. (wikipedia.org)
  • When two heteromeric hemichannels join, it is also called a heterotypic Gap Junction channel. (wikipedia.org)
  • Gap junctions form when two opposing connexons, or hemichannels, join across the intracellular space, or the space between two adjacent cells. (wisegeek.com)
  • Gating of Gap Junction Channels and Hemichannels in the Lens: A Role in Cataract? (elsevier.com)
  • Although gap junctions/hemichannels are known to modulate DNA synthesis via Ca 2+ waves, the role of Ca + oscillations and the mechanism of nuclear translocation in the VZ precursors are unclear. (jneurosci.org)
  • Here, we provide evidence that, during apical nuclear migration, VZ precursors display dynamic spontaneous Ca 2+ transients, which depend on functional gap junctions/hemichannels via ATP release and Ca 2+ -mobilizing messenger diffusion. (jneurosci.org)
  • Furthermore, we found that blocking gap junctions/hemichannels or short hairpin RNA-mediated knockdown of Cx43 (connexin 43) retards the apically directed interkinetic nuclear migration accompanied with changes in the nuclear length/width ratio. (jneurosci.org)
  • In addition, we demonstrated that blocking functional gap junctions/hemichannels induces phosphorylation of small GTPase cdc42 in the VZ precursors. (jneurosci.org)
  • Our findings indicate that functional interference with gap junctions/hemichannels during embryonic development may lead to abnormal corticogenesis and dysfunction of the cerebral cortex in adult organisms. (jneurosci.org)
  • Encompassing studies from animal, clinical, cellular and molecular perspectives, we plan to give a broad overview in the understanding of how gap junctions, hemichannels and pannexons are involved in the physiology and pathophysiology of the nervous system. (frontiersin.org)
  • Gap junction (GJ) mediates intercellular communication through linked hemichannels from each of two adjacent cells. (nih.gov)
  • The gap junction cellular internet: connexin hemichannels enter the signalling limelight. (bio-rad.com)
  • and 2) communication via gap junctions and/or hemichannels is required to initiate this protection. (aspetjournals.org)
  • To evaluate the contribution of gap junctions/hemichannels, additional control and d - myo -IP 3 -treated cohorts received a 5-min infusion of heptanol or Gap 27, two structurally distinct gap junction inhibitors, administered at doses confirmed to attenuate intercellular transmission of a gap junction-permeable fluorescent dye. (aspetjournals.org)
  • These data support the concepts that infarct size reduction with d - myo -IP 3 is triggered by receptor binding and that communication via gap junctions/hemichannels is involved in initiating this protection. (aspetjournals.org)
  • Homotypic gap junction channels are defined to consist of two identical hemichannels made from one type of connexin. (ahajournals.org)
  • Roles of gap junctions and hemichannels in bone cell functions and in signal transmission of mechanical stress. (semanticscholar.org)
  • Abstract -Gap junctions are formed by oligomerization of a protein called connexin. (ahajournals.org)
  • Targeting different domains of gap junction protein to control malignant glioma Wang, Jun;Yang, Ze-Yu;Guo, Yu-Feng;Kuang, Jing-Ya;Bian, Xiu-Wu;Yu, Shi-Cang 2017-11-02 00:00:00 Abstract A rational treatment strategy for glioma, the most common primary central nervous system tumor, should focus on early invasive growth and resistance to current therapeutics. (deepdyve.com)
  • Conductance through gap junctions formed of the connexin43 (Cx43) protein is decreased after stimulation of G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptors (GPCRs) at the cell surface, but the actual mechanism of channel regulation has been unclear. (sciencemag.org)
  • The authors confirmed decreased conductance of gap junctions formed from Cx43 in cells transfected with an active form of the G protein alpha subunit Gα q . (sciencemag.org)
  • Cx43 (a1 ) Gap Junctions in Cardiac Development and Disease, R.G. Gourdie and C.W. Lo . (elsevier.com)
  • To explore dependence of this effect on gap junctions, we co-transduced cells with a LV encoding a dominant-negative connexin43 mutant (Cx43Δ) as a molecular gap junction blocker. (ahajournals.org)
  • In this study, we show that AF cells express high levels of CX43 (GJA1) and are able to establish functional gap junctions with cortical cultures. (biomedsearch.com)
  • Among the phenotypic consequences of connexin loss, some appear to reflect the role of gap junctions as ion conductors, such as the loss of retinal rod signaling, cortical asynchrony (Cx36), partial conductance block (Cx40) and ventricular arrhythmias (Cx43) in the heart, and K + recycling in the ear (Cx26 and Cx30). (biologists.org)
  • Yet other defects illustrate the probable role of gap junctions in mediating intercellular signaling, such as coordination of neural crest migration (Cx43), oocyte maturation (Cx37 and Cx43), myelin development (Cx32 and Cx47), coordination of hepatic sympathetic responses (Cx32) and morphogenesis of the heart, blood, bone, vasculature (Cx43 and Cx45) and skin (Cx26, Cx30 and Cx30.3). (biologists.org)
  • Immunoreactive sites for the gap junction protein connexin 43 (Cx43) were detected in the marrow stromal cells and in mature osteoclasts. (diva-portal.org)
  • TCDD showed a decrease in GJIC in MCF-7 cells caused by increased phosphorylation of gap junctional protein, Cx43. (k-state.edu)
  • The data are interpreted on the basis of previous studies from our laboratory that demonstrated heterodomain interactions in the regulation of Cx40 and Cx43 gap junctions. (ahajournals.org)
  • Consequently, we proposed that a heteromeric gap junction containing both Cx40 and Cx43 may be more sensitive to pH i than the homomeric channels. (ahajournals.org)
  • 9 In the present study, we looked at the pH sensitivity of gap junctions formed in Xenopus oocytes coexpressing Cx40 and Cx43. (ahajournals.org)
  • The aim of the present study has been to investigate the possible formation of heterotypic gap junction channels between Cx40 and Cx43. (ahajournals.org)
  • Our findings indicate that, in brain and in cultured astrocytes, several of these coexpressed genes encode proteins that are components of P2R signal-transduction pathways and/or directly interact with these receptors, including the gap junction protein connexin43 (Cx43) and Cx45 as well as pannexins. (ad-astra.ro)
  • In cultures obtained form from Cx36 knockout mice, re-expression of functional gap junction channels, containing either neuronal Cx36 or non-neuronal Cx43 or Cx31, resulted in increased neuronal death following insult. (ku.edu)
  • The decrease In gap junctional communication was associated with tyrosine phosphorylation of the gap junction protein, connexin43 (Cx43). (hawaii.edu)
  • Since the presence of phosphotyrosine on Cx43 is correlated with the down regulation of gap-junctional communication, these results suggest that pp60v-src regulates gap junctional gating activity via tyrosine phosphorylation of Cx43. (hawaii.edu)
  • By the co-expression of Cx43 and SUMO1 in cancer stem cells, the gap junction intercellular communication (GJIC) of liver cancer stem cells was obviously improved. (spandidos-publications.com)
  • Connexin 43 (Cx43), a gap junction protein, plays important roles not only in the development of the central nervous system and but also in the progression of glioma. (deepdyve.com)
  • Gap junctions contain intercellular channels that allow direct communication between the cytosolic compartments of adjacent cells. (genome.jp)
  • Gap junction channels are intercellular channels that allow passage of ions, such as K(+) and Na(+) , and other small molecules between neighboring cells. (bio-rad.com)
  • Gap junctions are intercellular channels that allow for the passage of ions and small molecules between cells in a tissue. (ahajournals.org)
  • Invertebrate gap junctions comprise proteins from the innexin family . (wikipedia.org)
  • genes can produce only the proteins that make up gap junction channels. (wikipedia.org)
  • When two identical hemichannel proteins come together to form a Gap junction channel, it is called a homotypic GJ channel. (wikipedia.org)
  • Gap junctions (GJs) are composed of proteins that form a channel connecting the cytoplasm of adjacent cells. (nih.gov)
  • Cx37 is a member of a family of gap junction proteins that can assemble a comparatively nonselective channel when cells come into close contact with each other. (ahajournals.org)
  • Database search has led to the identification of a family of proteins, the pannexins, which share some structural features with the gap junction forming proteins of invertebrates and vertebrates. (pnas.org)
  • Because they share structural features with gap junction proteins of invertebrates and vertebrates, we investigated their tissue distribution and analyzed their ability to form functional channels. (pnas.org)
  • Epidermal growth factor (EGF) is known to regulate conductance of gap junctions through mitogen-activated protein kinase-dependent phosphorylation of the connexin proteins that form gap junction channels. (sciencemag.org)
  • Negative: Physiology: What Connexin-Deficient Mice Reveal about the Functional Roles of Individual Gap Junction Proteins, D.C. Spray, T. Kojima, E. Scemes, S.O. Suadicani, Y. Gao, S. Zhao, and A. Fort . (elsevier.com)
  • This protein sequence is homologous to the well-characterized gap junction structural proteins rat connexin32 and connexin43. (sciencemag.org)
  • Pannexin 1 and pannexin 3 are glycoproteins that exhibit many distinct characteristics from the connexin family of gap junction proteins. (thefreedictionary.com)
  • GJB4 and GJB6 code for gap junction proteins connexin 30.3 and connexin 30, respectively. (thefreedictionary.com)
  • The GJA12/GJC2 (GJA12 was recently renamed GJC2) encodes the gap junction protein connexin47 (Cx47), which is a member of the connexin family of highly conserved integral membrane proteins. (cags.org.ae)
  • Therefore, we investigated the role of substituted quinolines (PQ1), shown to bind with gap junctional proteins by computational docking. (k-state.edu)
  • Furthermore, SNPs-induced apoptosis through the disrupted functional gap junction was correlated with abnormal expressions of the proteins involved in the mitochondrial pathway-related apoptosis such as Bcl-2/Bax, cytochrome C, Caspase-9, and Caspase-3. (sigmaaldrich.com)
  • Interestingly, inhibitors of channels formed by proteins of the gap junction family, such as suramin and boldine, exhibit trypanocidal activity. (intechopen.com)
  • Gap junction proteins are integral membrane proteins present in both vertebrates and invertebrates that participate in cellular communication. (intechopen.com)
  • These proteins form gap junction channels, which connect the cytoplasm of neighboring cells or non-junctional channels that connect the intra- and extracellular milieu. (intechopen.com)
  • Interestingly, Trypanosoma cruzi modulates the expression of proteins of the gap junction family or modify the activity of the channels formed by these proteins in host cells. (intechopen.com)
  • In this chapter, we summarized the current knowledge about the possible roles of gap junction family proteins in Chagas disease. (intechopen.com)
  • Interestingly, inhibitors of channels formed by proteins of the gap junction family such as suramin and boldine have trypanocidal activity and some of them are currently used for treatment of parasitic diseases such Human African Trypanosomiasis [ 2 , 3 , 4 , 5 ]. (intechopen.com)
  • Also, studies have shown that infections caused by Trypanosoma cruzi ( T. cruzi ) modulate the expression of proteins of the gap junction family or modify the activity of the channels formed by these proteins in host cells [ 6 , 7 , 8 , 9 , 10 , 11 ]. (intechopen.com)
  • This intercellular transfer is dependent on the presence of functional gap junctions and is capable of mediating knockdown of both exogenous and endogenous genes. (ahajournals.org)
  • Human amniotic fluid cells form functional gap junctions with cortical cells. (biomedsearch.com)
  • Connexin expression and formation of functional gap junctions is modulated by stroma cell density. (scielo.br)
  • Presence of functional gap junctions in human embryonic stem cells. (wikipathways.org)
  • Tramadol and flurbiprofen, but not morphine, significantly reduced cisplatin cytotoxicity, but this effect required functional gap junctions between the cells. (aacrjournals.org)
  • 12 16 17 18 19 20 However, not every homomeric hemichannel will form a functional gap junction channel with another homomeric hemichannel derived from a different connexin. (ahajournals.org)
  • These data indicate that the restoration of functional gap junctions is likely a critical event in the antiproliferative action of the sst2 receptor. (asm.org)
  • Protein component of gap junctions which are specialized regions of the plasma membrane formed by a cluster of channels allowing small molecules to diffuse from the cytosol of one cell to that of an adjacent cell. (uniprot.org)
  • The identification of connexin36 (Cx36) as the main neuronal connexin expressed in several areas of the brain ( 18 ), suggested that it may be an important component of gap junctions involved in the synchronization of large-scale neuronal networks. (pnas.org)
  • A new dominant allele, leo tK3 , leads to a complete loss of the pattern, suggesting a dominant negative impact on another component of gap junctions. (elifesciences.org)
  • Rather, we shall argue for a role for a newly described sort of gap junction, located between the proximal axons of principal neurons. (springer.com)
  • Such axon-axon gap junctions promote epileptogenesis not so much by enhancing synchrony, as by providing pathways for the direct spread of action potentials between neurons. (springer.com)
  • Electrical coupling also occurs between adjacent neurons at specialized junctions called electrical synapses. (wisegeek.com)
  • It is generally accepted that gap junctions between neurons represent the anatomical substrate of electrical synapses (reviewed in refs. (pnas.org)
  • Also, whenever possible, we describe the strength of gap junctions between pairs of neurons, represented as either the junctional conductance or the coupling coefficient (i.e. the change in membrane potential of a post-junctional cell divided by the change in the membrane potential in a pre-junctional cell when then membrane potential of the pre-junctional cell is altered). (utah.edu)
  • For instance, modifying the strength of gap junction coupling can significantly alter the receptive field size of retinal neurons by modifying the strength and extent of their excitatory receptive field surround. (utah.edu)
  • I am trying to understand how to use a ParallelContext class with a network of neurons connected by gap junctions across nodes. (yale.edu)
  • Diverse gap junctions are found between various retinal neurons, (40,41) and electrical transmission through gap junctions serves various lateral interactions. (thefreedictionary.com)
  • On the other hand, nearby dendrite domain of different neurons in the same area may undergo a similar or identical gap junction effect. (cryonet.org)
  • A rough estimate of the activity can be deduced from nearby neurons and that may be sufficient to actualise the gap junction potential. (cryonet.org)
  • Taken together, these results suggest a role for neuronal gap junctions in cell death via a connexin type-independent mechanism that likely relies on channel activities of gap junctional complexes among neurons. (ku.edu)
  • Fontes JD, Ramsey J, Polk JM, Koop A, Denisova JV, Belousov AB (2015) Death of Neurons following Injury Requires Conductive Neuronal Gap Junction Channels but Not a Specific Connexin. (ku.edu)
  • This network includes the channels embedded in the plasma membranes of adjacent cells that come together to form gap junctions, or direct passageways between the cytoplasm of a cell and its neighbors. (utexas.edu)
  • Using pharmacological blockade of neuronal gap junctions combined with electrophysiological recordings, we found that gap junctions play a role in theta rhythm in the vHIP and mPFC of adult mice. (sigmaaldrich.com)
  • Collectively, these findings suggest that neuronal gap junctions in the vHIP-mPFC pathway are important for theta rhythm and anxiety regulation under sedentary conditions but that additional mechanisms are likely involved in running-induced reduction in anxiety. (sigmaaldrich.com)
  • Characterization of connexin36 gap junctions in the human outer retina. (nih.gov)
  • Here, we provide an overview of electrical coupling in the retina and outline the varied roles that gap junctions play in processing information in healthy and diseased states. (utah.edu)
  • Interestingly, microcircuits in the retina are connected through both chemical synapses and bi-directional electrical synapses formed by gap junctions. (utah.edu)
  • In addition, gap junctions exert their effects over a range of spatial scales, synchronizing activity at the sub-cellular level as well as across wide swaths of the retina. (utah.edu)
  • In slices of retina from Cx36-GCaMP transgenic mice, approximately half of fluorescent gap junctions imaged in the inner plexiform layer responded to 2 sec puffs of glutamate with fluorescence increases lasting 10-15 sec. (arvojournals.org)
  • Many gap junctions in the retina experience transient Ca 2+ increases dependent on NMDA receptors. (arvojournals.org)
  • A Reexamination of Calcium Effects on Gap Junctions in Heart Myocytes, B. Delage and J. Délèze . (elsevier.com)
  • In the present study we ascertain the functional presence of gap junctions between principal cells of Malpighian tubules of the yellow fever mosquito. (biologists.org)
  • The ubiquitous presence of gap junctions in the metazoa has suggested that they are essential for multicellular life - a conclusion that is supported by the array of different human diseases and mouse phenotypes that arise from defects in these genes. (biologists.org)
  • It's not altered second messenger production that shuts down the channel but rather the action of PLC-β3 to deplete membrane concentrations of PtdIns(4,5)P 2 , which appears to directly modulate conductance of gap junctions as it does other ion channels and transporters. (sciencemag.org)
  • Channel composition influences the function of gap junction channels. (wikipedia.org)
  • Gap junction channels (tens to thousands) assemble within a macromolecular complex called a gap junction plaque. (wikipedia.org)
  • A current model of the gap junction consists of a cluster of gap-junction channels. (uniprot.org)
  • Gap junctions are cylindrical channels between animal cells that allow small molecules and ions to pass from the inside of one cell to the inside of the adjacent cell. (wisegeek.com)
  • Hormones are important messenger chemicals, many of which cannot pass through cell membranes on their own and require the help of secondary messengers and channels such as gap junctions. (wisegeek.com)
  • Vertebrate gap junction channels are thought to participate in diverse biological functions. (ebi.ac.uk)
  • One gap junction consists of a cluster of closely packed pairs of transmembrane channels, the connexons, through which materials of low MW diffuse from one cell to a neighboring cell. (uniprot.org)
  • The functional characteristics of homomeric Px1 versus heteromeric Px1/Px2 channels and the different expression patterns of Px1 and Px2 in the brain indicate that pannexins form cell type-specific gap junctions with distinct properties that may subserve different functions. (pnas.org)
  • Gap junction channels allow communication in the form of small molecules that flow between adjacent cells. (sciencemag.org)
  • Immunoprecipitation experiments showed that PLC-β3 associated with the scaffold protein ZO-1 (zona occludens 1), and depletion of ZO-1 with RNAi also reduced receptor-mediated regulation of gap junction channels. (sciencemag.org)
  • Receptor-induced depletion of phosphatidylinositol 4,5-bisphosphate inhibits conductance of gap junction channels. (sciencemag.org)
  • Heteromultimeric Gap Junction Channels and Cardiac Disease, S. Elenes and A.P. Moreno . (elsevier.com)
  • Ion Permeation through Connexin Gap Junction Channels: Effects on Conductance and Selectivity, R.D. Veenstra . (elsevier.com)
  • Biophysical Properties of Hemi-Gap-Junctional Channels Expressed in Xenopus Oocytes, L. Ebihara and J. Pal . (elsevier.com)
  • This resistance would stem from 6190 open gap-junctional channels, assuming the high single gap-junction conductance of 375 pS found in vertebrate tissues. (biologists.org)
  • The diversity of gap junction channel properties, defined above for channels composed of one connexin, is further increased by the expression of multiple connexin isotypes in most cells. (biologists.org)
  • Gap junction channels allow exchange of intracellular ions and molecules as large as 1 kDa between dying and viable brain cells, exchanged that has been suggested to be detrimental or beneficial, depending on the nature of the insult (ie, ischemia or trauma). (ahajournals.org)
  • In other paradigms, the NCA cation channels act upstream of gap junctions. (genetics.org)
  • Rod and cone photoreceptors are coupled by gap junctions (GJs), relatively large channels able to mediate both electrical and molecular communication. (elifesciences.org)
  • Gap junction channels seem to be involved in several ways in the pathophysiology of migraine with aura and emerge as a new promising putative target in treatment of this disorder. (frontiersin.org)
  • Gap junctions are clusters of intercellular channels connecting adjacent cells and permitting the direct exchange of ions and small molecules between cells. (wikipathways.org)
  • The activity of these intercellular channels is regulated, particularly by intramolecular modifications such as phosphorylation which appears to regulate connexin turnover, gap junction assembly and the opening and closure (gating) of gap junction channels. (wikipathways.org)
  • Multiple pathways in the trafficking and assembly of connexin 26, 32 and 43 into gap junction intercellular communication channels. (wikipathways.org)
  • Researchers propose using channels embedded in plasma membranes of adjacent cells, known as the gap junction network (in green), as passageways for delivery of RNA interference therapeutics. (utexas.edu)
  • Objective This study investigated whether chondrocytes within the cartilage matrix have the capacity to communicate through intercellular connections mediated by voltage-gated gap junction (GJ) channels. (bmj.com)
  • The functions of gap-junction channels and CxHcs have been difficult to separate, but synthetic peptides that mimic short sequences in the Cx subunit are emerging as promising tools to determine the role of CxHcs in physiology and pathology. (portlandpress.com)
  • In addition, Gap channels are specialized cell-cell contacts that allow passive diffusion of molecules up to 1 kDa, including nutrients, metabolites (glucose), ions (K+, Ca2+) and second messengers (IP3, cAMP). (cags.org.ae)
  • Cell-to-cell communication is achieved by passage of small molecules through gap junction membrane channels. (biomedsearch.com)
  • Gap junctions, strongly implicated as channels for direct cell-to-cell communication, have been isolated from rat liver in high yield and purity. (caltech.edu)
  • Gap junctional intercellular channels allow the cells to communicate with each other. (k-state.edu)
  • Gap junction intercellular communication (GJIC) between cardiomyocytes is essential for synchronous heart contraction and relies on connexin-containing channels. (sigmaaldrich.com)
  • Moreover, Lucifer yellow microinjected into fibroblast was incorporated into associated trypanosomes of Trypanosoma musculi, suggesting the possibility of direct communication via gap junction channels between them. (intechopen.com)
  • 6 7 8 This finding immediately raises the question about the types of gap junction channels present. (ahajournals.org)
  • 2-Aminoethoxydiphenyl borate (2-APB), an inositol 1,4,5-triphosphate receptor modulator, inhibits capacitive current transients measured in normal rat kidney and human embryonic kidney 293 cells, an indication of blocking gap junction channels between these cells. (aspetjournals.org)
  • 2-APB dose-dependently and reversibly blocked junctional currents of connexin (Cx) 50 gap junction channels. (aspetjournals.org)
  • The blocking action of 2-APB did not substantially alter transjunctional voltage-dependent gating of Cx50 gap junction channels, and recordings from poorly coupled pairs of Cx50-transfected N2A cells indicated that 2-APB reduced gap junction channel open probability without changing the main state single-channel conductance. (aspetjournals.org)
  • Gap junction channels connect the cytoplasm of adjacent cells, allowing direct intercellular exchange of ions and small signaling molecules with molecular masss below approximately 1 kDa. (aspetjournals.org)
  • However, only very few drugs have been identified that block gap junction channels, and most of these are nonspecific, acting on other channel types. (aspetjournals.org)
  • These channels-known as gap junctions-allow neighbouring cells to communicate with each other. (elifesciences.org)
  • Each gap junction is made up of two half channels, with one half coming from each neighbouring cells. (elifesciences.org)
  • heteromeric' gap junctions are made from two different half channels, each consisting of a different connexin protein. (elifesciences.org)
  • Gap junction (GJ) channels directly connect the cytoplasm of neighboring cells, and allow for the transfer of ions and small molecules between two cells. (uwo.ca)
  • In general, allows transmembrane movement of molecules smaller than 485 Daltons [21] (1,100 Daltons through invertebrate gap junctions [22] ), although different hemichannel subunits may impart different pore sizes and different charge selectivity. (wikipedia.org)
  • gap junction ( nexus ) A passage through the lipid bilayers of adjacent plasma membranes that mediates the transfer of small molecules or ions between interacting cells. (encyclopedia.com)
  • gap junction A communicating junction between cells, which provides a rapid passage for ions and small molecules such that they need not cross the bilipid layer of the opposed membranes. (encyclopedia.com)
  • Gap junctions are cell-to-cell connections that allow for the passage of molecules or electrical currents through cells. (reference.com)
  • Gap junctions only let ions, or charged particles, and small molecules up to about 1,000 daltons pass through into the next cell. (wisegeek.com)
  • These observations raise two possibilities: either a different connexin is specifically deployed throughout the pyramidal cell network or, alternatively, another class of molecules expressed in the mammalian brain forms electrical junctions between pyramidal cells. (pnas.org)
  • Gap junctions allow cytoplasmic molecules to move from one cell to another, and such communication appears to influence a broad range of processes, including development, cell proliferation, and behavior of cancer cells. (sciencemag.org)
  • Small tracer molecules such as Neurobiotin pass through the gap junction pore, marking interconnected cells. (utah.edu)
  • Gap junctions are specialised pores which allow small molecules and charge to pass between cells. (clinicaltrials.gov)
  • Gap junctions were first defined morphologically as specialized contacts between cells that mediate the direct exchange of small molecules needed to coordinate behavior of multicellular systems. (biologists.org)
  • Taken together, our results suggests that gap junctional diffusion of messenger molecules interacts with signaling pathways downstream RANKL in osteoclast differentiation. (diva-portal.org)
  • The assembly of gap junctions (GJs) is a process coordinated by growth factors, kinases, and other signaling molecules. (rupress.org)
  • Between 2 adjacent cells, connexons connect end-to-end to form gap junction structures that mediate a more extensive exchange of molecules (soluble second messengers, amino acids, nucleotides, Ca2+, glucose and its metabolites, nucleotides, amino acids, and peptides), which is termed gap junctional intercellular communication (GJIC). (deepdyve.com)
  • The junction of two adjacent connexons forms a gap-junction channel. (uniprot.org)
  • A gap of approximately 3 nm remains between the adjacent cell membranes, but two connexons interact and dock head-to-head in the extra-cellular space forming a tightly sealed, double-membrane intercellular channel (see Segretain and Falk, 2004). (wikipathways.org)
  • Dynamic trafficking and delivery of connexons to the plasma membrane and accretion to gap junctions in living cells. (wikipathways.org)
  • The hemichannel pair connect across the intercellular space bridging the gap between two cells. (wikipedia.org)
  • Large biomolecules, for example, nucleic acid and protein , are precluded from cytoplasmic transfer between cells through gap junction hemichannel paris. (wikipedia.org)
  • These junctions are a particular feature of cells that are in direct electrical coupling with one another (e.g. nerve and heart muscle cells, and perhaps embryonic cells). (encyclopedia.com)
  • Gap junctions are found in cardiac and smooth muscle, where they function to increase the speed of electrical communication, or depolarization, between cells. (reference.com)
  • In addition to gap junctions, other types of junctions include anchoring junctions and desmosomes, which keep muscle cells connected when they contract. (reference.com)
  • The three principle functions of gap junctions are containing damaged cells, metabolic coupling, and electrical coupling. (wisegeek.com)
  • The junctions communicate death signals between cells and shut down in response to heightened intracellular calcium levels and low pH. (wisegeek.com)
  • Possible communication diversity is increased further by the fact that gap junctions may be formed by the association of different connexin isoforms from apposing cells. (ebi.ac.uk)
  • Gap junctions are recognized in the electron microscope as dense starchy areas of opposed membrane between two cells. (utah.edu)
  • We present electrical, physiological and molecular evidence for substantial electrical coupling of epithelial cells in Malpighian tubules via gap junctions. (biologists.org)
  • By short-circuiting the transepithelial voltage with the diuretic peptide leucokinin-VIII we largely eliminated electrical coupling of principal cells through the tubule lumen, thereby allowing coupling through gap junctions to be analyzed. (biologists.org)
  • The analysis of an equivalent electrical circuit of the tubule yielded an average gap-junction resistance ( R gj ) of 431 kΩ between two cells. (biologists.org)
  • Thus, gap junctions couple neighboring cells directly, whereas the tubule lumen couples them indirectly. (biologists.org)
  • While direct effects have been clearly demonstrated in siRNA-transduced cells, we investigated a possible "bystander effect" whereby siRNAs transfer between transduced and non-transduced (NT) primary neonatal rat ventricular myocytes (NRVMs) via gap junctions. (ahajournals.org)
  • Here we show that activation of the innate immune system by double-stranded DNA (dsDNA) triggers intercellular communication through a gap junction-dependent signaling pathway, recruiting colonies of cells to collectively secrete antiviral and inflammatory cytokines for the propagation of danger signals across the tissue at large. (mit.edu)
  • Gap junctions form punctate `plaques' at the interfaces between cells, although protein is often seen trapped in the ER and Golgi in some disease-associated mutants. (biologists.org)
  • The primary function ascribed to gap junctions has been the transfer of ions and metabolites under about 1000 Da between cells in contact. (biologists.org)
  • We examined the effects of nitric oxide (NO), an important mediator of vasomotion, wound healing and angiogenesis, on the formation of gap junctions in endothelial cells (human umbilical vein endothelial cells, HUVEC). (uni-muenchen.de)
  • Conclusions: We conclude that NO is a potent modulator of gap-junctional coupling in endothelial cells. (uni-muenchen.de)
  • A more direct pathway for cellular crosstalk is provided by gap junction intercellular channel, which allows adjacent cells to exchange second messengers, ions, and cellular metabolites. (diva-portal.org)
  • 1 Apoptotic and necrotic signals may spread from stressed to neighboring cells through gap junctions, amplifying the extent of injury. (ahajournals.org)
  • We therefore propose that increased gap junction communication in the stroma elicits an enhanced production of immature bone marrow cells through the delay in their terminal differentiation, inducing consequently an extended proliferation period of blood cell precursors. (scielo.br)
  • However, 'gap junctions' that connect the rods and cones allow for electrical and chemical 'crosstalk' between these cells, before the signals then travel along the optic nerve. (elifesciences.org)
  • When studied via gap junctions , lactate is more rapidly discharged from cancer cells than protons, which are highly-buffered by a variety of intracellular bases [41]. (thefreedictionary.com)
  • The double membrane channel, or gap junction, is generated directly and couples the cytoplasms of the interacting cells. (bio-rad.com)
  • Endothelin-1 decreases gap junctional intercellular communication by inducing phosphorylation of connexin 43 in human ovarian carcinoma cells. (wikipathways.org)
  • Defective activation of c-Src in cystic fibrosis airway epithelial cells results in loss of tumor necrosis factor-alpha-induced gap junction regulation. (wikipathways.org)
  • We present in this article an improvement of this model, including gap junction models at any interface between cells. (inria.fr)
  • We then test this approach on hand-crafted two-dimensional networks of a hundred of cells, and compare it with our previous model which did not include gap junctions modelling. (inria.fr)
  • The double membrane channel or gap junction generated directly couples the cytoplasms of interacting cells and underpins the integration and co-ordination of cellular metabolism, signalling and functions, such as secretion or contraction in cell assemblies. (portlandpress.com)
  • In contrast, CxHcs prior to forming gap junctions provide a pathway for the release from cells of ATP, glutamate, NAD + and prostaglandin E 2 , which act as paracrine messengers. (portlandpress.com)
  • ATP activates purinergic receptors on neighbouring cells and forms the basis of intercellular Ca 2+ signal propagation, complementing that occuring more directly via gap junctions. (portlandpress.com)
  • To determine whether connexin43, a major gap junction protein expressed in fibroblasts, is a target for the v-src protein tyrosine kinase activity, we examined the phosphorylation state of connexin43 in cells expressing variants of src. (biomedsearch.com)
  • Short-term exposure of transformed cells to cisplatin reduced the clonogenic survival in low-density cultures (without gap junction formation) and in high density (with gap junction formation), but the toxic effect was greater at high density. (aacrjournals.org)
  • Our findings suggest that germ line stem cells differentiate upon losing contact with their niche, that gap junction mediated cell-cell interactions are required for germ cell differentiation, and that in Drosophila germ line stem cell differentiation to a cystoblast is gradual. (biologists.org)
  • Here we show that a gap junction protein is required for differentiation of female germ-line stem cells (GSCs) in the fruit fly Drosophila melanogaster . (biologists.org)
  • As a next step, it will be important to identify the signals that pass through these gap junctions that allow the cells to communicate with their neighbours and establish the pigmentation pattern. (elifesciences.org)
  • Cells that do not synthesize DNA, on the other hand, show normal levels and distribution of immunoreactive gap junction protein. (caltech.edu)
  • Gap junctions and purinergic P2 receptors (P2Rs) can be regarded as belonging to a common functional unit, given that they are involved in the transmission of calcium signals between cells. (ad-astra.ro)
  • Endodermal cells in situ have large 1.5 μm diameter gap junctions composed of 8 nm P-face particles and corresponding E-face pits. (springer.com)
  • The dissociation of endoderm into single cells involves profound structural alterations in the surface membrane including the complete disappearance of junctional structures among them gap junctions. (springer.com)
  • The observation that the dissociation and reaggregation of endodermal cells involves IMP alterations which go beyond the cell junctions themselves is discussed as an adaptation of the plasma membrane to changing environmental conditions. (springer.com)
  • Bennett MVL, Trinkaus JP (1970) Electrical coupling between embryonic cells by way of extracellular space and specialized junctions. (springer.com)
  • Johnson R, Hammer M, Sheridan J, Revel JP (1974) Gap junction formation between reaggregated Novikoff hepatoma cells. (springer.com)
  • Normal differentiated and contact-inhibited cells express at least one connexin isoform that assembles, alone or in combination, into gap junctions. (asm.org)
  • Consistently, the lack of growth control and the inability to differentiate or apoptose in most cancer cells are related to altered connexin expression and consequent dysfunctional gap junction intercellular communication. (asm.org)
  • Transfected cells, regarded as the lowest level of complexity, are a very useful and reliable tool to study the effects of gap junction phosphorylation. (uu.nl)
  • Scrape load/dye transfer studies showed that 100 nM of PQ15, a third generation substituted quinoline, causes a 4.5-fold increase of gap junction activity in T47D breast cancer cells. (k-state.edu)
  • Here, we investigated the involvement of gap junction intercellular communication (GJIC) during anchorage-independent clustering of MCF7 breast adenocarcinoma cells. (biomedcentral.com)
  • High levels of adrenomedullin expression enhanced adhesion of tumor cells to LECs, and further analysis revealed that adrenomedullin promoted gap junction coupling between LECs as evidenced by spread of Lucifer yellow dye. (ovid.com)
  • Adrenomedullin also enhanced heterocellular gap junction coupling as demonstrated by Calcein dye transfer from tumor cells into LECs. (ovid.com)
  • This connexin-mediated gap junction intercellular communication was necessary for tumor cells to undergo transendothelial migration because pharmacological blockade of this heterocellular communication prevented the ability of tumor cells to transmigrate through the lymphatic monolayer. (ovid.com)
  • Among these, signal transduction can be coordinated among several cells due to gap junctional permeability to intracellular second messengers. (semanticscholar.org)
  • Several laboratories have demonstrated a decrease in gap junctional communication in cells transformed by the src oncogene of the Rous sarcoma virus. (hawaii.edu)
  • In a realistic model of two electrically connected mitral cells, the paper shows that the somatically-measured experimental properties of Gap Junctions (GJs) may correspond to a variety of different local coupling strengths and dendritic distributions of GJs in the tuft. (yale.edu)
  • Gap junctions are abundant in epithelial tissues and cardiac muscle . (encyclopedia.com)
  • Functional analysis of human cardiac gap junction channel mutants. (wikipathways.org)
  • In the heart, gap junctions play an essential role in cardiac development and in electrical synchrony. (ahajournals.org)
  • Communication through Gap Junction is sensitive to a variety of stimuli, including changes in the level of intracellular Ca2+, pH, transjunctional applied voltage and phosphorylation/dephosphorylation processes. (genome.jp)
  • Capitanio, "Subcytotoxic mercury chloride inhibits gap junction intercellular communication by a redox- and phosphorylation-mediated mechanism," Free Radical Biology & Medicine, vol. (thefreedictionary.com)
  • Tyrosine phosphorylation of a gap junction protein correlates with inhibition of cell-to-cell communication. (biomedsearch.com)
  • Because loss of gap junction communication has been associated with carcinogenesis and enhanced EGF signaling also contributes to some forms of cancers, the authors note that the newly described regulatory pathway could have a role in tumorigenesis. (sciencemag.org)
  • Inhibiting gap junctions decreases dsDNA-induced IRF3 activation, cytokine production, and the resulting tissue-wide antiviral state, indicating that this immune response propagation pathway lies upstream of the paracrine action of secreted cytokines and may represent a host-derived mechanism for evading viral antiinterferon strategies. (mit.edu)
  • Gap junctions in the ventral hippocampal-medial prefrontal pathway are involved in anxiety regulation. (sigmaaldrich.com)
  • ECM-receptor interaction, fatty acid metabolism, TGF-beta signaling, and gap junction pathway were involved in these predicted pathways. (thefreedictionary.com)
  • Inhibition of gap junction intercellular communication is involved in silica nanoparticles-induced H9c2 cardiomyocytes apoptosis via the mitochondrial pathway. (sigmaaldrich.com)
  • It enhances de novo formation of endothelial gap junctions by increasing incorporation of Cx40 into the plasma membrane due to PKA activation. (uni-muenchen.de)
  • In addition, treatment of LECs with adrenomedullin caused nuclear translocation of β-catenin, a component of endothelial cell junctions, causing an increase in transcription of the downstream target gene C-MYC. (ovid.com)
  • Gap junctions, together with chemical synapses (which function through neurotransmitters ), are communicating junctions and comprise one of several types of cell junction . (encyclopedia.com)
  • Given these diverse roles for gap junctions in retinal signal processing, it is not surprising that electrical synapses also play many roles in disease states. (utah.edu)
  • For electrical synapses, when known, we outline the connexin subtypes involved in forming gap junctions and describe their biophysical properties. (utah.edu)
  • Despite the characterizations of coupling strength that we will outline below, it is important to keep in mind that the conductance through a gap junction is not static, and changes to the conductance can have significant effects on the roles that electrical synapses play in neuronal circuits. (utah.edu)
  • Gap junctions aid metabolic coupling through allowing chemical second messengers such as calcium ions and cyclic adenosine monophosphate - also known as cAMP or cyclic AMP - to pass into the adjacent cell's cytoplasm . (wisegeek.com)
  • The addition of the calcium ionophore A23187 (2 μmol l -1 ) to the peritubular Ringer bath containing 1.7 mmol l -1 Ca 2+ did not affect the gap-junction resistance, but metabolic inhibition of the tubule with dinitrophenol (0.5 mmol l -1 ) increased the gap-junction resistance 66-fold, suggesting the regulation of gap junctions by ATP. (biologists.org)
  • Perez-Velazquez JL, Valiante TA, Carlen PL. Modulation of gap junctional mechanisms during calcium-free induced field burst activity: a possible role for electrotonic coupling in epileptogenesis. (springer.com)
  • Gap junctions are essential to the body's proper functioning due to their role in electrical coupling. (wisegeek.com)
  • Role of Gap Junctions in Cellular Growth Control and Neoplasia: Evidence and Mechanisms, R.J. Ruch . (elsevier.com)
  • Connexin 43 Expression on Peripheral Blood Eosinophils: Role of Gap Junctions in Transendothelial Migration," BioMed Research International , vol. 2014, Article ID 803257, 8 pages, 2014. (hindawi.com)
  • It represents a useful tool with which to examine the role of gap junctions in EDHF activity in vivo. (clinicaltrials.gov)
  • Gap junctions in the early amphibian embryo may play a fundamental role in the regulation of differentiation by mediating the cell-to-cell transfer of chemical signals. (sciencemag.org)
  • Here we have investigated the role of gap junction communication in osteoclastogenesis in mouse bone marrow cultures. (diva-portal.org)
  • To study the role of gap junctions in the development of proliferative retinal disease. (arvojournals.org)
  • Our results indicate that gap junctions play a significant role in the development of proliferative retinopathy. (arvojournals.org)
  • Shawn Divitt, Palash Bharadwaj, and Lukas Novotny, "The role of gap plasmons in light emission from tunnel junctions," Opt. (osapublishing.org)
  • The role of gap junctions in the modulation of cisplatin toxicity is explored by manipulation of connexin expression, and gap junction presence and function, using clinically relevant concentrations of the analgesics and cisplatin. (aacrjournals.org)
  • In this review, we focus on the role of ubiquitin and its effect on gap junction intercellular communication. (biochemsoctrans.org)
  • In particular, we consider the neuroprotective role of astrocyte gap junction coupling. (umn.edu)
  • We postulate that the quantitative changes in gap junction expression might play an important role in the control of proliferation in the liver. (caltech.edu)
  • 1 . Migliore M, Hines ML, Shepherd GM (2005) The role of distal dendritic gap junctions in synchronization of mitral cell axonal output. (yale.edu)
  • NEURON mod files from the paper: M. Migliore, M. Hines and GM Shepherd The role of distal dendritic gap junctions in synchronization of mitral cell axonal output, J. Comput. (yale.edu)
  • When one homomeric hemichannel and one heteromeric hemichannel come together, it is called a heterotypic gap junction channel. (wikipedia.org)
  • The results show a heightened sensitivity to intracellular acidification when compared with that of homomeric/homotypic gap junctions. (ahajournals.org)
  • Moreover, as the strength of gap junctions can be modified over a variety of timescales, they can reconfigure retinal microcircuits on both a millisecond time-scale as well as over the course of the day/night cycle. (utah.edu)
  • Finally, despite the advances outlined here regarding our understanding of the various roles for gap junctions in retinal signaling, it is likely that we are still only scratching the surface in identifying the full repertoire of their functional roles. (utah.edu)
  • Changes to coupling strength could also modify other roles for gap junctions in retinal circuits. (utah.edu)
  • The communication with the gap junction appeared to require PtdIns(4,5)P 2 itself, rather than IP 3 or DAG, and channel inhibition could be reproduced by depletion of PtdIns(4,5)P 2 with an engineered version of phosphoinositide 5-phosphatase targeted to the plasma membrane. (sciencemag.org)
  • Johnson, "Inhibition of gap junction and adherens junction assembly by connexin and A-CAM antibodies," The Journal of Cell Biology, vol. (thefreedictionary.com)
  • They further indicate that tramadol and flurbiprofen depress cisplatin cytotoxicity through inhibition of gap junction activity, and more generally, that agents that depress junctional communication can counteract the effects of antitumor agents. (aacrjournals.org)
  • Inhibition of gap junctions by gap junction blocker carbenoxolone disodium resulted in decreased survival and increased apoptosis, whereas enhancement of the gap junctions by retinoic acid led to enhanced survival but decreased apoptosis. (sigmaaldrich.com)
  • The concentration-inhibition curve of 2-APB on the junctional current indicated an IC 50 of 3.7 μM, lower than that of most gap junction inhibitors. (aspetjournals.org)
  • Gap junction protein connexin-43 interacts directly with microtubules. (bio-rad.com)
  • Interaction of c-Src with gap junction protein connexin-43. (wikipathways.org)
  • The consequence of connexin coexpression on the regulation of gap junctions is not well understood. (ahajournals.org)
  • Decker RS (1976) Hormonal regulation of gap junction differentiation. (springer.com)
  • As a functional entity, they have evolved independently three times, if one includes plasmodesmata in plants, which are structurally very distinct from gap junctions but mediate similar functions. (biologists.org)
  • Gap junctions mediate intercellular calcium signalling in cultured articular chondrocytes. (semanticscholar.org)
  • To form a gap junction channel, each cell of an adjacent pair synthesizes a hemichannel composed of six connexin subunits called a connexon. (asm.org)
  • Gap junctions are a specialized intercellular connection between a multitude of animal cell -types. (wikipedia.org)
  • Gap junctions occur in virtually all tissues of the body, with the exception of adult fully developed skeletal muscle and mobile cell types such as sperm or erythrocytes . (wikipedia.org)
  • Skeletal muscle does not contain any type of cell-to-cell junctions, including gap junctions. (reference.com)
  • The gap junctions permit the passage of current from one cell to the next, but they prohibit the passage of the dye Lucifer Yellow. (biologists.org)
  • We examined gap junction communication in an in vitro model of hematopoiesis, using the murine bone marrow stroma cell line S-17, and primary cultures of murine marrow-derived blood cell precursors. (scielo.br)
  • Interestingly, in the time course of animal model trials, tonabersat was shown to inhibit trigeminal ganglion (TGG) neuronal-glial cell gap junctions, suggesting that this compound could prevent peripheral sensitization within the ganglion. (frontiersin.org)
  • A lot of previous work has focused on disrupting cell membranes, but our work is the first to ask whether the gap junction network can be harnessed for gene silencing. (utexas.edu)
  • The same sequence of events, starting with the presence of the gap junction protein before cell-to-cell coupling becomes evident, was observed in the blastocyst-free segments 1 day later. (uni-stuttgart.de)
  • A breach in gap junctional intercellular communication (GJIC) affects cell growth and proliferation. (k-state.edu)
  • Here we show that the gap junction protein Zero population growth (Zpg) is required for germ cell differentiation in the Drosophila ovary. (biologists.org)
  • By the coordinate use of antibodies directed to the hepatic junction protein (HJP28) and the use of a monoclonal antibody that recognizes bromodeoxyuridine (BrdU) incorporated into DNA, we have been able to study the relationship between detectable gap junction protein and cell division. (caltech.edu)
  • In patients with breast cancer, the cell junction component plakoglobin is overexpressed compared with healthy tissue. (biomedcentral.com)
  • Degradation of Gap Junctions and Connnexins, J.G. Laing and E.C. Beyer . (elsevier.com)
  • Peracchia C (1980) Structural correlates of gap junctions permeation. (springer.com)
  • Gap junctional conductance is a simple and sensitive function of intracellular pH. (springer.com)
  • Gap junction formation was studied in the uterine epithelium of nonpregnant, pregnant, and pseudopregnant rabbits in the periimplantation phase (6, 7, 8 days post coitum/post human gonadotropin injection) using freeze-fracture and immunocytochemistry as well as intracellular Lucifer yellow injection. (uni-stuttgart.de)
  • In particular, the reestablishment of functional brain networks requires formation of gap junctions, as a key step to provide sufficient intercellular communication. (biomedsearch.com)
  • Thus, gap junction formation is one of the first maternal responses to a locally acting signal of the blastocyst. (uni-stuttgart.de)
  • Importantly, blockade of gap junction intercellular communication prevented β-catenin nuclear translocation. (ovid.com)
  • Gap junctional intercellular communication (GJIC) is thought to control tissue homeostasis and to coordinate cellular processes such as proliferation, migration and differentiation. (contemporaryobgyn.net)
  • Many studies have revealed that myocytes and fibroblasts are functionally coupled by gap junctions when fibrosis occurred and may interact and modify impulse conduction via two-way electronic signal [8-10]. (thefreedictionary.com)
  • Conclusions- Gap junction blockade may be a useful therapeutic tool to minimize brain damage produced by perinatal and early postnatal HI. (ahajournals.org)
  • In conclusion, downregulation of gap junctions can potentiate tumor growth while restoration of GJIC can induce apoptosis and decrease tumor growth. (k-state.edu)
  • Background and Purpose- We investigated the contribution of gap junctions to brain damage and delayed neuronal death produced by oxygen-glucose deprivation (OGD). (ahajournals.org)
  • A possible contribution of gap junction channel-permeable death signals in neuronal death is discussed. (ku.edu)
  • Gap Junction Communication in Invertebrates: The Innexin Gene Family, P. Phelan . (elsevier.com)
  • The p.Ala88Val (A88V) mutation in the gene coding for the gap-junction protein connexin30 (Cx30) protects the cochlear basal turn of adult CD-1 Cx30 A88V/A88V mice from degeneration and rescues hearing. (nature.com)
  • X-linked Charcot-Marie-Tooth type 1 (CMT1X) disease is a hereditary chronic progressive disease, which is caused by mutations in the gap junction beta-1 protein ( GJB1 ) gene encoding the gap junction protein connexin 32 (Cx32). (thefreedictionary.com)
  • Intercellular Calcium Wave Communication via Gap Junction-Dependent and -Independent Mechanisms, E. Scemes, S.O. Suadicani, and D.C. Spray . (elsevier.com)
  • This study investigates the effects of three commonly used analgesics, which produce analgesia by different mechanisms, on cytotoxicity induced by cisplatin, a widely used antitumor agent, and the relation between those effects and modulation of gap junction function by the analgesics. (aacrjournals.org)
  • The gap junction blocker carbenoxolone applied to hippocampal slice cultures before, during, or 60 minutes after OGD markedly reduced delayed neuronal death. (ahajournals.org)
  • Loss of this gap-junction protein abolishes electrical coupling between hippocampal interneurons and disrupts γ-frequency network oscillations in vitro and in vivo ( 15 , 24 ). (pnas.org)
  • Mechanistic Differences between Chemical and Electrical Gating of Gap Junctions, I.M. Skerrett, J.F. Smith, and B.J. Nicholson . (elsevier.com)
  • Electrical signals pass through these junctions, extending the region of neuronal data collection, modifying the dynamic properties of the signal, and synchronizing impulse generation. (utah.edu)