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 - 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 ...
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 ...
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 ...
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 ...
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
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.
... & 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 ...
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. ...
website is to go through reviews site. It is impossible for a man to date several women and If one guy dates two or more girls online at the same time, the result is always frustrating ...
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 ...
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 ...