Our experiments indicate that the incidence of electrical coupling in parental HeLa cells and RIN cells is low. After transfection with Cx40 or Cx43, coupling was enhanced ≈200-fold in Cx40-HeLa-Cx43-HeLa and Cx40-HeLa-Cx43-RIN cell pairs. This suggests formation of heterotypic Cx40-Cx43 channels.. The multichannel and single-channel data presented indicate that Cx40-Cx43 channels are present in Cx40-HeLa-Cx43-HeLa and Cx40-HeLa-Cx43-RIN cell pairs. With regard to multichannel data, the relationships gj, inst=f(Vj) and gj, ss=f(Vj) were asymmetrical, a property seen in heterotypic gap junctions whose connexons exhibit widely different properties (eg, Cx26-Cx3216 17 18 or Cx37-Cx43.12 21 In the case of Cx40-Cx43, rectification was prominent for both relationships, ie, gj, ss=f(Vj) and gj, inst=f(Vj) (see Figures 2C⇑ and 2D⇑). Voltage gating was almost exclusively observed at negative Vj. This is consistent with the notion that Cx40 is gating with positive polarity (V.V., R.W., P.R.B., ...
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 ...
TY - JOUR. T1 - The molecular basis of selective permeability of connexins is complex and includes both size and charge. AU - Nicholson, B. J.. AU - Weber, P. A.. AU - Cao, F.. AU - Chang, H. C.. AU - Lampe, P.. AU - Goldberg, G.. PY - 2000/4. Y1 - 2000/4. N2 - Although gap junction channels are still widely viewed as large, non-specific pores connecting cells, the diversity in the connexin family has led more attention to be focused on their permeability characteristics. We summarize here the current status of these investigations, both published and on-going, that reveal both charge and size selectivity between gap junction channels composed of different connexins. In particular, this review will focus on quantitative approaches that monitor the expression level of the connexins, so that it is clear that differences that are seen can be attributed to channel properties. The degree of selectivity that is observed is modest compared to other channels, but is likely to be significant for ...
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 ...
Connexin 30 (Cx30), a member of the large gap junction protein family, plays a role in the homeostasis of the epidermis and inner ear through gap junctional intercellular communication (GJIC). Here, we investigated the underlying mechanisms of four autosomal dominant Cx30 gene mutations linked to hearing loss and/or various skin diseases. First, the T5M mutant linked to non-syndromic hearing loss formed functional gap junction channels and hemichannels, similar to wild type Cx30. The loss-of-function V37E mutant associated with Clouston syndrome or keratitis-ichthyosis-deafness syndrome was retained in the endoplasmic reticulum and significantly induced apoptosis. The G59R mutant linked to Vohwinkel and Bart-Pumphrey syndromes was retained primarily in the Golgi apparatus and exhibited loss of gap junction channel and hemichannel function, but did not cause cell death. Lastly, the A88V mutant related to Clouston syndrome also significantly induced apoptosis, although through an endoplasmic ...
TY - JOUR. T1 - Regulation of connexin hemichannels by monovalent cations. AU - Srinivas, Miduturu. AU - Calderon, D. Paola. AU - Kronengold, Jack. AU - Verselis, Vytautas. PY - 2006/1. Y1 - 2006/1. N2 - Opening of connexin hemichannels in the plasma membrane is highly regulated. Generally, depolarization and reduced extracellular Ca2+ promote hemichannel opening. Here we show that hemichannels formed of Cx50, a principal lens connexin, exhibit a novel form of regulation characterized by extraordinary sensitivity to extracellular monovalent cations. Replacement of extracellular Na+ with K+, while maintaining extracellular Ca2+ constant, resulted in ,10-fold potentiation of Cx50 hemichannel currents, which reversed upon returning to Na+. External Cs+, Rb+, NH4+, but not Li +, choline, or TEA, exhibited a similar effect. The magnitude of potentiation of Cx50 hemichannel currents depended on the concentration of extracellular Ca2+, progressively decreasing as external Ca 2+ was reduced. The primary ...
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 ...
Connexins (Cxs) and pannexins (Panxs) are highly regulated large-pore channel-forming proteins that participate in cellular communication via small molecular exchange with the extracellular microenvironment, or in the case of connexins, directly between cells. in Cx40?/? mice was further exaggerated in double knockout mice. Thus, while gestation and gross development were conserved in Cx40?/?Panx1?/? mice, they exhibit cardiac hypertrophy, hypertension, and impaired endothelial-mediated vasodilation that phenocopies Cx40?/? mice. Nevertheless, the augmented renin homeostasis observed in the double knockout mice suggests that both Cx40 and Panx1 may play an integrative role. [3C5]. Conversely, the most well-understood pannexin, pannexin1 (Panx1), has been demonstrated to form large-pore membrane channels, which facilitate autocrine/paracrine-mediated signaling via the release of purine nucleotides, most notably ATP [6]. Within the mammalian cardiovascular system (cardiac tissue and peripheral ...
Individual cell-cell channels consist of two hemichannels, located on neighboring cell membranes, that are interconnected to form an hydrophilic pathway. Each hemichannel, or connexon, is made of six protein subunits, called connexins.Connexin32 liver gap junction protein has four transmembrane segments, two extracellular regions and three cytoplasmic segments, which include the amino and carboxyl termini.The process of cell-cell channel formation was investigated by altering specific amino acids in the presumed extracellular domains of the connexin32. It is these domains that must interact when two hemichannels dock to form an open cell-cell channel. The mutant connexins were generated by site-directed in vitro mutagenesis of a connexin32 cDNA. The mutated cDNAs were then transcribed in vitro and the mRNA was injected into Xenopus oocytes for expression. Junctional conductances between paired oocytes resulting from the expression of the mRNA were measured by the double-voltage clamp technique.Every
Communication among cells via direct cell-cell contact by connexin gap junctions, or between cell and extracellular environment via pannexin channels or connexin hemichannels, is a key factor in cell...
Connexins (Cx) (TC# 1.A.24), or gap junction proteins, are structurally related transmembrane proteins that assemble to form vertebrate gap junctions. An entirely different family of proteins, the innexins, form gap junctions in invertebrates. Each gap junction is composed of two hemichannels, or connexons, which consist of homo- or heterohexameric arrays of connexins, and the connexon in one plasma membrane docks end-to-end with a connexon in the membrane of a closely opposed cell. The hemichannel is made of six connexin subunits which are themselves each constructed out of six connexin molecules[clarification needed]. Gap junctions are essential for many physiological processes, such as the coordinated depolarization of cardiac muscle, proper embryonic development, and the conducted response in microvasculature. For this reason, mutations in connexin-encoding genes can lead to functional and developmental abnormalities. Connexins are commonly named according to their molecular weights, e.g. ...
Gap junctions are intercellular channels made of connexins (Cxs) that allow direct communication between adjacent cells. Modulation of Cxs has been associated with abnormal development and function of the mammary gland and breast cancer. However, the mechanisms underlying their expression during normal mammary gland are not yet known. Cxs interact with components of tight and adherens junctions. Thus, we hypothesized that the expression levels of Cxs vary during mammary gland development and are regulated through stage-dependent interactions with members of the tight and adherens junctions. Our specific objectives were to: 1) determine the expression of Cxs and tight and adherens junction proteins throughout development and 2) characterize Cxs interactions with components of tight and adherens junctions. Murine mammary glands were sampled at various developmental stages (pre-pubescent to post-weaning). RT-qPCR and western-blot analyses demonstrated differential expression patterns for all gap ...
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 ...
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
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 ...
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). ...
Sigma-Aldrich offers abstracts and full-text articles by [Peter J Minogue, Jun-Jie Tong, Anita Arora, Isabelle Russell-Eggitt, David M Hunt, Anthony T Moore, Lisa Ebihara, Eric C Beyer, Viviana M Berthoud].
The three major blood cell types, i.e., platelets, erythrocytes and leukocytes, are all produced in the bone marrow. While red blood cells are the most numerous and white cells are the largest, platelets are small fragments and account for a minor part of blood volume. However, platelets display a crucial function by preventing bleeding. Upon vessel wall injury, platelets adhere to exposed extracellular matrix, become activated, and form a platelet plug preventing hemorrhagic events. However, when platelet activation is exacerbated, as in rupture of an atherosclerotic plaque, the same mechanism may lead to acute thrombosis causing major ischemic events such as myocardial infarction or stroke. In the past few years, major progress has been made in understanding of platelet function modulation. In this respect, membrane channels formed by connexins and/or pannexins are of particular interest. While it is still not completely understood whether connexins function as hemichannels or gap junction channels to
Buy our Recombinant Human Connexin 37 / GJA4 protein. Ab114495 is a full length protein produced in Wheat germ and has been validated in WB, ELISA, SDS-PAGE…
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 ...
Buy anti-cx35 antibody, Mouse Connexin 35 Monoclonal Antibody (Clone 2Q2144)-NP_919401.1 (MBS603567) product datasheet at MyBioSource, Primary Antibodies. Application: Immunohistochemistry (IHC)
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 ...
In humans, connexins (Cxs) and pannexins (Panxs) are the building blocks of hemichannels. These proteins are frequently altered in neoplastic cells and have traditionally been considered as tumor suppressors. Alteration of Cxs and Panxs in cancer cells can be due to genetic, epigenetic and post-transcriptional/post-translational events. Activated hemichannels mediate the diffusional membrane transport of ions and small signaling molecules. In the last decade hemichannels have been shown to participate in diverse cell processes including the modulation of cell proliferation and survival. However, their possible role in tumor growth and expansion remains largely unexplored. Herein, we hypothesize about the possible role of hemichannels in carcinogenesis and tumor progression. To support this theory, we summarize the evidence regarding the involvement of hemichannels in cell proliferation and migration, as well as their possible role in the anti-tumor immune responses. In addition, we discuss the evidence
We have shown previously that postnatal cardiac-restricted deletion of N-cadherin leads to complete dissolution of the intercalated disc structure with a modestly dilated cardiomyopathy.21 We noted sudden death in a majority of animals ≈6 to 8 weeks after inducing deletion of N-cadherin in the heart that was correlated with the onset of spontaneous ventricular arrhythmias. The mechanism by which depleting N-cadherin creates a substrate for ventricular arrhythmogenesis and sudden death in this model is not entirely clear, but is likely related to loss of functional gap junctions.. In line with the role of connexins contributing to the arrhythmogenic substrate, the more comprehensive EP analysis presented in the current study reveals striking similarities between the phenotypes of Cx43 CKO models generated by other groups10,11 and our N-cadherin CKO mice. Surface ECG analysis shows that the QRS amplitude is significantly reduced in N-cadherin CKO mice, similar to that seen in Cx43 CKO mice.10,28 ...
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 ...
Gentaur molecular products has all kinds of products like :search , AbD \ MOUSE ANTI MOUSE CONNEXIN 43-MONOCLONAL ANTIBODY \ 2260-1010 for more molecular products just contact us
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: : ...
This gene encodes 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 have been associated with atherosclerosis and a higher risk of myocardial infarction. [provided by RefSeq, Jul 2008] ...
The major risk factors for atherosclerosis are aging, hypertension, hyperlipidemia, smoking, and diabetes. These conditions influence endothelium biology. ECs display GJs, and connexin expression is tightly regulated. Deregulation can occur in different pathological conditions that will be discussed here.. Aging seems to induce a general decrease in connexin expression, with Cx40 being relatively undisturbed for a long time (138). Nicotine induces a decrease in Cx43 expression due to an enhanced protein degradation (121).. Hypertension is a cause of ECs dysfunction and a major risk factor of atherosclerosis. Hypertensive rats have a reduced endothelial expression of Cx37 and Cx43, but Cx40 expression is not modified (141). Moreover, carvedilol, a commonly used β-blocker for hypertension and cardioprotection, directly upregulates endothelial Cx43 independently of its antioxidant activity (141).. Oxidation products of lipoprotein-derived phospholipids upregulate Cx43 and downregulate Cx37 but do ...
SR GROUP - Exporter, Importer, Manufacturer, Distributor, Supplier, Trading Company of Rat CX31(Connexin 31) ELISA Kit based in Delhi, India
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 ...
Sigma-Aldrich offers abstracts and full-text articles by [Anna R Moore, Wen-Liang Zhou, Carissa L Sirois, Glenn S Belinsky, Nada Zecevic, Srdjan D Antic].
Activation of the inflammasome, a complex that processes interleukin-1β (IL-1β), occurs in response to activation of the adenosine triphosphate receptor P2X7 on macrophages. Activation of P2X7 also triggers the opening of a nonselective, large pore in the plasma membrane. Pelegrin and Surprenant found that pannexin-1 (panx1), a protein that produces hemichannel currents when ectopically expressed in oocytes, was present in monocytes, macrophages, astrocytes, and various cell lines. Panx1, when expressed in transfected HEK cells, coimmunoprecipitated with the P2X7 receptor and colocalized with the P2X7 receptors in ATP-stimulated cells. Using either an siRNA to knock down panx1 or a peptide inhibitor to block the pore function of panx1, the authors showed that dye uptake (a measure of pore opening) in response to P2X7 required panx1. When overexpressed in cells that lack P2X7 receptors, panx1 caused constitutive dye uptake, and when overexpressed in cells that contain P2X7 receptors, panx1 ...
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
New research has identified hundreds of metabolites that could one day help doctors better monitor metabolite variation as an indicator of disease.
ORTHO I PTMA 366034 36InX60InX3/4In - anti fatigue mats & logo mats, shop at Ultimate Mats for all commercial, residential, office, & industrial.
Description of the drug Maxi-Tuss HCX Liquid. - patient information, description, dosage and directions. What is Maxi-Tuss HCX Liquid!
ED raided Karti Chidambarams premises of Delhi and Chennai today over INX media case. The court has issued fresh summon to the son of former Union Finance Minister P. Chidambaram after he skipped his appearance before the court in the INX media money laundering case.
Phosphorylation of wt or mutant Cx43 in v-Src-expressing cells. (A) Immunoprecipitation of Cx43. Confluent cells were metabolically labeled with 32Pi. Cx43 wa
Hello everybody Im a second year student of molecular biology, and have just startet on a project about connexins and their assembly into connexons. In my readings I find that Triton X-100 soulubility is used to tell something about the proteins, but what? Can anyone in this newsgroup please tell me what the TX-100 soulubility is good for. Has it got something to do with phosphorylation of the proteins? Thanks Ulrik ...
Organizations that want to extend vSphere environments into the cloud are often daunted by the challenges that come with adopting a cloud strategy. VMware HCX can help by providing the components necessary to deploy an interconnected infrastructure without needing to modify existing environments.
ISOLUTE® HCX is a mixed-mode sorbent providing clean extracts for basic compounds from complex biological fluid samples using a dual retention mechanism.
ISOLUTE® HCX is a mixed-mode sorbent providing clean extracts for basic compounds from complex biological fluid samples using a dual retention mechanism.
Subscribe to free, weekly science newsletters to keep current with research, industry news, policy news and events relevant to your field.
This week we had 3 inx pairs give. No phenotype were observed and RFP was unsortable at d6 when attempted. Results for inx screen are inconclusive. ...
Formation of platelet plug initiates hemostasis at sites of vascular injury, and triggers pathological thrombosis in ischemic tissue disease. Although various crucial molecules for platelet function have been identified in recent years, the mechanisms of inter- and intra-cellular signaling leading to the formation of a stable platelet plug is still poorly understood. Connexins form gap junctions, clusters of intercellular channels that are known to synchronize responses in multi-cellular organisms through the direct exchange of ions, small metabolites and other second messenger molecules between adjacent cells. Here, we report the expression of the gap junction protein connexin37 (Cx37) in mouse and human platelets. In addition, we observed functional gap junction communication between platelets during platelet aggregation in vitro, as assessed by microinjection of the gap junction-permeable tracer neurobiotin in platelets isolated from human or wild-type mice. In contrast, the tracer did not ...
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 ...
TY - JOUR. T1 - Coincidence of mutations in different connexin genes in Hungarian patients. AU - Tóth, Tímea. AU - Kupka, Susan. AU - Haack, Birgit. AU - Fazakas, Ferenc. AU - Muszbek, LáSzló. AU - Blin, Nikolaus. AU - Pfister, Markus. AU - Sziklai, István. PY - 2007/9. Y1 - 2007/9. N2 - Mutations in the GJB2 gene are the most common cause of hereditary prelingual sensorineural hearing impairment in Europe. Several studies indicate that different members of the connexin protein family interact to form gap junctions in the inner ear. Mutations in different connexin genes may accumulate and, consequently lead to hearing impairment. Therefore, we screened 47 Hungarian GJB2-heterozygous (one mutation in coding exon of the GJB2 gene) patients with hearing impairment for DNA changes in two further connexin genes (GJB6 and GJB3) and in the 5′ non-coding region of GJB2 including the splice sites. Eleven out of 47 GJB2-heterozygous patients analyzed carried the splice site mutation -3170G,A in 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 ...
Methods and results - Thirty New Zealand rabbits were randomly divided into three experimental groups: myocardial infarction, carvedilol and control groups. The left anterior descending coronary artery was ligated in animals in the myocardial infarction group; in the control animals no artery was ligated. The animals in the carvedilol group were administered carvedilol by way of gavages at a dose of 0.5 mg/kg. After the experiment had gone on for 8 weeks, the spatial distribution and the amount of gap junction protein connexin 40 in the left auricle ware measured by fluorescence immunohistochemistry and Western blot, respectively. Compared with the controls, the amount of left atrial appendage gap junction protein connexin 40 in the myocardial infarction group was significantly decreased (P < 0.01), and an uneven distribution of gap junction protein connexin 40 was markedly observed. The amount of gap junction protein connexin 40 in the carvedilol group was higher than that in the myocardial ...
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 ...
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 ...
TY - JOUR. T1 - Impaired trafficking of connexins in androgen-independent human prostate cancer cell lines and its mitigation by α-catenin. AU - Govindarajan, Rajgopal. AU - Zhao, Sumin. AU - Song, Xiao Hong. AU - Guo, Rong Jun. AU - Wheelock, Margaret. AU - Johnson, Keith R.. AU - Mehta, Parmender P. PY - 2002/12/20. Y1 - 2002/12/20. N2 - Gap junctions, composed of connexins, provide a pathway of direct intercellular communication for the diffusion of small molecules between cells. Evidence suggests that connexins act as tumor suppressors. We showed previously that expression of connexin-43 and connexin-32 in an indolent prostate cancer cell line, LNCaP, resulted in gap junction formation and growth inhibition. To elucidate the role of connexins in the progression of prostate cancer from a hormone-dependent to -independent state, we introduced connexin-43 and connexin-32 into an invasive, androgen-independent cell line, PC-3. Expression of these proteins in PC-3 cells resulted in intracellular ...
Purpose: To screen for mutations of connexin50 (Cx50)/GJA8 in a panel of patients with inherited cataract and to determine the cellular and functional consequences of the identified mutation.. Methods: All patients in the study underwent a full clinical examination and leucocyte DNA was extracted from venous blood. The GJA8 gene was sequenced directly. Connexin function and cellular trafficking were examined by expression in Xenopus oocytes and HeLa cells.. Results: Screening of the GJA8 gene identified a 139 G to A transition that resulted in the replacement of aspartic acid by asparagine (D47N) in the coding region of Cx50. This change co-segregated with cataract among affected members of a family with autosomal dominant nuclear pulverulent cataracts. While pairs of Xenopus oocytes injected with wild type Cx50 RNA formed functional gap junction channels, pairs of oocytes injected with Cx50D47N showed no detectable intercellular conductance. Co-expression of Cx50D47N did not inhibit gap ...
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 ...
Mutations in the gap junction geneconnexin32(Cx32) cause the X-linked form of Charcot-Marie-Tooth disease, an inherited demyelinating neuropathy. More than 130 different mutations have been described, affecting all portions of the Cx32 protein. In transfected cells, the mutant Cx32 proteins encoded by someCx32mutations fail to reach the cell surface; other mutant proteins reach the cell surface, but only one of these forms functional gap junctions. In peripheral nerve, Cx32 is localized to incisures and paranodes, regions of noncompact myelin within the myelin sheath. This localization suggests that Cx32 forms
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 ...
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 ...
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 ...
TY - JOUR. T1 - Extracellular loop cysteine mutant of Cx37 fails To suppress proliferation of rat insulinoma cells. AU - Good, Miranda E.. AU - Ek-Vitorín, José F.. AU - Burt, Janis M.. PY - 2012/7. Y1 - 2012/7. N2 - Although a functional pore domain is required for connexin 37 (Cx37)-mediated suppression of rat insulinoma (Rin) cell proliferation, it is unknown whether functional hemichannels would be sufficient or if Cx37 gap junction channels are required for growth suppression. To test this possibility, we targeted extracellular loop cysteines for mutation, expecting that the mutated protein would retain hemichannel, but not gap junction channel, functionality. Cysteines at positions 61 and 65 in the first extracellular loop of Cx37 were mutated to alanine and the mutant protein (Cx37-C61,65A) expressed in Rin cells. Although the resulting iRin37-C61,65A cells expressed the mutant protein comparably to Cx37 wild-type (Cx37-WT)-expressing Rin cells (iRin37), Cx37-C61,65A expression did not ...
TY - JOUR. T1 - A role for an inhibitory connexin in testis?. AU - Chang, Michelle. AU - Werner, Rudolf. AU - Dahl, Gerhard. N1 - Funding Information: The expert technical help by Audrey Llanes is appreciated. This work was supported by National Institutes of Health grants GM48610 (to G.D.) and GM40583 (to R.W.).. PY - 1996/4/10. Y1 - 1996/4/10. N2 - Functional expression of gap junction proteins can be obtained conveniently with the paired oocyte cell-cell channel assay. So far all gap junction proteins (connexins), with the exception of one, have been found to make: functional channels either by themselves or as hybrid channels (two hemichannels of different connexin composition). Connexin33 (cx33) appears not to follow this rule. Expression of cx33 in oocytes does not yield functional channels, and attempts to identify another connexin with which cx33 can form hybrid channels have failed so far. The observation was made that cx33 inhibits functional expression of other connexins in a ...
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 ...
TY - JOUR. T1 - A novel missense mutation in the second extra cellular domain of GJB2, p.Ser183Phe, causes a syndrome of focal palmoplantar keratoderma with deafness. AU - de Zwart-Storm, E. A.. AU - van Geel, M.. AU - van Neer, P. A.F.A.. AU - Steijlen, P. M.. AU - Martin, Patricia E.M.. AU - van Steensel, M. A.M.. N1 - Originally published in: American Journal of Pathology (2008), 173 (4), pp.1113-11179.. PY - 2008/10/1. Y1 - 2008/10/1. N2 - Gap junctions, which consist of connexins, are intercellular channels that mediate rapid intercellular communication. In the skin, connexins are involved in the regulation of epidermal growth and differentiation. GJB2 encodes connexin26, which is an important skin-expressed gap junction protein. Mutations in GJB2 cause a wide variety of unique disorders, but despite extensive research, their mechanisms of action are poorly understood. The identification of novel diseases caused by mutations in GJB2 may help to illuminate the genotype-phenotype correlation ...
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 ...
Learning, knowledge, research, insight: welcome to the world of UBC Library, the second-largest academic research library in Canada.
Gap junction channels formed by alpha3 (Cx46) and alpha8 (Cx50) connexin provide pathways for communication between the fiber cells in the normal transparent lens. To determine the specific role of alpha3 connexin in vivo, the alpha3 connexin gene was disrupted in mice. Although the absence of alpha …
Mouse Connexin-23 ELISA Kit;Mouse Cx23 ELISA Kit;Mouse AEY12 ELISA Kit;Mouse D230044M03Rik ELISA Kit;Mouse Gjf1 ELISA Kit;Mouse Gsfaey12 ELISA Kit;Mouse gap junction protein, epsilon 1 ELISA Kit;Mouse gap junction epsilon-1 protein ELISA Kit;Mouse connexin 23 ELISA Kit;Mouse putative gap junction protein connexin Cx43.4 ELISA Kit ...
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 ...
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 ...
We examined changes in the expression and localization of connexin proteins and transcripts by means of immunofluorescence and in situ hybridization in normal conditions, wound healing and carcinogenesis using hamster tongue epithelium, in which differentiation, migration and growth of keratinocytes takes place physiologically and pathologically. In normal hamster tongue epithelium, immunofluorescent staining showed that Cx26 and Cx43 proteins were localized differently during differentiation of keratinocytes, but in in situ hybridization, the localization of Cx26 and Cx43 transcripts overlapped considerably, suggesting that the different localization of Cx26 and Cx43 proteins in squamous epithelium is largely regulated at post-transcriptional levels. During wound healing, the expression and localization of connexin proteins and transcripts were changed drastically. Shortly (6 h) after injury the expression of Cx26 and Cx43 proteins decreased at wound edges, but by 1-3 days after injury the ...
MIM *0608803 Alternative titles; symbols •GAP JUNCTION PROTEIN, ALPHA 12; GJA12 •GAP JUNCTION PROTEIN, 47-KD •CONNEXIN 47; CX47 CONNEXIN 46.6; CX46.6 Gene map locus: 1q41-q42 Text For background information on connexins, see CX26 (GJB2; 121011). Cloning The complete coding sequence of the GJA12 gene has been deposited in GenBank (AF014643). The GJA12 sequence encodes a 436-amino acid protein (GenBank AAB94511). Gene Function Gap junction proteins are members of a large family of homologous connexins and comprise 4 transmembrane, 2 extracellular, and 3 cytoplasmic domains. They have been identified in a broad range of mammalian tissues, and most tissues expressed more than 1 species of connexin protein.Menichella et al. (2003) found that Cx47 (Gja12) is expressed specifically in oligodendrocytes and that its expression is regulated in parallel with other myelin genes. Cx47 and Cx32 (Gjb1; 304040) partially colocalized in oligodendrocytes, which together with Schwann cells synthesize the ...
Apoptotic cells release the nucleotides ATP and UTP to attract phagocytic cells, which in turn clear the apoptotic cells. Chekeni et al. found that carbenoxolone (CBX), which inhibits connexins (which form gap junctions) and pannexins (which form plasma membrane channels), and probenicid, which is thought to be more specific for pannexins, reduced ATP release from apoptotic Jurkat cells to a similar extent as the caspase inhibitor zVAD (which blocks the release of ATP from apoptotic cells). Small interfering RNAs (siRNAs) directed against pannexin 1 (PANX1) decreased the release of ATP and UTP from apoptotic Jurkat cells but did not prevent apoptosis. Supernatant from PANX1 siRNA-transfected apoptotic cells recruited fewer monocytes in an in vitro assay of cell migration and when placed in a subcutaneous air pouch in mice. In contrast, Jurkat cells stably overexpressing PANX1 released more ATP and UTP, and supernatants from these cells (after apoptosis had been induced) recruited more monocytes ...
Fibroblasts play a significant role in the development of electrical and mechanical dysfunction of the heart; however, the underlying mechanisms are only partially understood. One widely studied mechanism suggests that fibroblasts produce excess extracellular matrix, resulting in collagenous septa t …
Gap junctions allow intercellular communication. Their structural subunits are four-transmembrane proteins named connexins (Cxs), which can be post-transcriptionally regulated by developmental and cellular signalling cues. Cx translation and mRNA stability is regulated by miRNAs and RNA-binding proteins (RBPs) such as human antigen R (HuR). In addition, several Cxs have also been suggested to contain 5′ internal ribosome entry site (IRES) elements that are thought to allow cap-independent translation in situations such as mitosis, stress and senescence. Furthermore, several recent reports have documented internal translation of Cx mRNAs that result in N-terminally truncated protein isoforms that may have unique gap junction-independent functions [Ul-Hussain et al. (2008) BMC Mol. Biol. 9, 52; Smyth and Shaw (2013) Cell Rep. 5, 611-618; Salat-Canela et al. (2014) Cell Commun. Signal. 12, 31; Ul-Hussain et al. (2014) J. Biol. Chem. 289, 20979-20990]. This review covers the emerging field of the ...
Cardiac myocytes and fibroblasts form extensive networks in the heart, with numerous anatomical contacts between cells. Fibroblasts, obligatory components of the extracellular matrix, represent the majority of cells in the normal heart, and their number increases with aging and during disease. The myocyte network, coupled by gap junctions, is generally believed to be electrically isolated from fibroblasts in vivo. In culture, however, the heterogeneous cell types form functional gap junctions, which can provide a substrate for electrical coupling of distant myocytes, interconnected by fibroblasts only. Whether similar behavior occurs in vivo has been the subject of considerable debate. Recent electrophysiological, immunohistochemical, and dye-coupling data confirmed the presence of direct electrical coupling between the two cell types in normal cardiac tissue (sinoatrial node), and it has been suggested that similar interactions may occur in post-infarct scar tissue. Such heterogeneous cell ...
HeLa cells seem not to be junctionally coupled when probed with techniques such as Lucifer yellow spreading and/or ionic coupling measured with three inserted microelectrodes. When investigated with double whole-cell patch-clamp measurements, HeLa cells in monolayer cultures were electrically coupled in 39% of the cases with very low transjunctional conductances (average one to five open channels). These gapjunction channels had a single-channel conductance γ=26±6 pS and were voltage-gated with an equivalent gating charge ζ=3.1±1.5 for a voltage of half-maximal inactivation Uo=49±10 mV. The voltage-dependent component represents only 31±8% of the total junctional conductance. The voltage-insensitive conductance is characterized by a residual open probability po(∞)=0.34±0.12, which corresponds to a ratio Gmin/Gmax=0.50±0.12. Dissociation of monolayer cells into cell pairs yielded about 58% coupled cell pairs with no notably altered single-channel properties ...
The progressive death of retinal ganglion cells and resulting visual deficits are hallmarks of glaucoma, but the underlying mechanisms remain unclear. In many neurodegenerative diseases, cell death induced by primary insult is followed by a wave of secondary loss. 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. Here we have shown that pharmacological blockade of GJs or genetic ablation of connexin 36 (Cx36) subunits, which are highly expressed by retinal neurons, markedly reduced loss of neurons and optic nerve axons in a mouse model of glaucoma. Further, functional parameters that are negatively affected in glaucoma, including the electroretinogram, visual evoked potential, visual spatial acuity, and contrast sensitivity, were maintained at control levels when Cx36 was ablated. Neuronal GJs may thus represent potential ...
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 ...
Read Connexins in Lens Development and Cataractogenesis, The Journal of Membrane Biology on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
Neuronal gap junctions are pervasive in structures of the CNS during development. As our results demonstrate, the TRN is no exception. In fact, during the first postnatal week the other major category of thalamic neurons-thalamocortical relay cells-are also coupled by gap junctions (Lee et al., 2006), as are their targets, pyramidal cells and spiny stellate cells of the neocortex (Connors et al., 1983; Lo Turco and Kriegstein, 1991; Yuste et al., 1992). Unlike the principal neurons of both rodent thalamus and neocortex, however, TRN neurons and inhibitory interneurons of the neocortex (Galarreta and Hestrin, 1999, 2002; Gibson et al., 1999) remain coupled after the early postnatal period. This striking divergence suggests different functions for the gap junctions of immature and mature neurons in the thalamus.. Gap junction channels have been implicated in a variety of tasks, including intercellular signaling with electrical (ionic) current, passage of intercellular chemical messengers, ...
Yancey, S. Barbara and Biswal, Sandip and Revel, Jean-Paul (1992) Spatial and temporal patterns of distribution of the gap junction protein connexin43 during mouse gastrulation and organogenesis. Development, 114 (1). pp. 203-212. ISSN 0950-1991. http://resolver.caltech.edu/CaltechAUTHORS:YANdev92 ...
Wu, C.-L., Shih, M.-F. M., Lai, J. S.-Y., Yang, H.-T., Turner, G. C., Chen, L. , Chiang, A. S. (2011) Heterotypic Gap Junctions between Two Neurons in the Drosophila Brain Are Critical for Memory. Current Biology, 21 (10). pp. 848-854. ISSN 0960-9822 ...
We have discovered a requirement for a novel connexin gene (frm-cx) in specification of the anterior neural plate in the invertebrate chordate Ciona. (The conne...
Compare gap junction protein, alpha 4, 37kDa Biomolecules from leading suppliers on Biocompare. View specifications, prices, citations, reviews, and more.
Compare gap junction protein, alpha 6 Biomolecules from leading suppliers on Biocompare. View specifications, prices, citations, reviews, and more.
In agreement with previous reports (11, 13, 18, 26, 44), the present data indicate that connexin mimetic peptides inhibit the formation of gap junction channels by binding to their target sequence, the connexins. However, the peptides did not have an acute effect on the nonjunctional membrane channels formed by the connexin chimera used in this study. Only over a time span of hours, a retardation of the typical increase in membrane conductance was observed. This slow effect is inconsistent with a gating mechanism of the channel and is even too slow to account for alteration of channel activity due to peptide-induced secondary modifications of the protein. Instead, the time course is consistent with the life-time of the protein, and it is thus conceivable that the bound peptide tags the protein for degradation.. All three connexin mimetic peptides tested here, however, attenuated the currents carried by membrane channels formed by the unrelated protein pannexin1. A scrambled version of the ...