Disease relevance of Gap Junctions

• To study the possible involvement of other members of the connexin family in hereditary hearing impairment, we cloned the gene (GJB3) encoding human gap junction protein beta-3 using homologous EST searching and nested PCR [1].
• Exposure of this tissue to retinoic acid (vitamin-A) (20 U/ml) in organ culture, however, induces mucous metaplasia, accompanied by tight-junction formation and gap-junction growth; untreated specimens continue to keratinize [2].
• Two sources of material are used: rat liver gap junctions and gap junctions produced by infecting insect cells with a baculovirus containing the cDNA for human liver beta 1 protein (connexin 32) [3].
• We studied mechanically induced calcium waves in two rat osteosarcoma cell lines that differ in the gap junction proteins they express, in their ability to pass microinjected dye from cell to cell, and in their expression of P2Y2 (P2U) purinergic receptors [4].
• To characterize the channel properties of the major rat liver gap junction protein (connexin 32) in isolation from other gap junction proteins, we have introduced the cDNA encoding it into a human hepatoma cell line (SKHep1) in which we have identified a gap junction deficiency [5].

Psychiatry related information on Gap Junctions

• We recorded rhythmic inspiratory motor activity from one or both phrenic nerves before and during pharmacological blockade (i.e., uncoupling) of brain stem gap junctions using carbenoxolone (100 microM), 18alpha-glycyrrhetinic acid (25-100 microM), 18beta-glycyrrhetinic acid (25-100 microM), octanol (200-300 microM), or heptanol (200 microM) [6].

High impact information on Gap Junctions

• Gap junction channels formed by alpha3 (Cx46) and alpha8 (Cx50) connexin provide pathways for communication between the fiber cells in the normal transparent lens [7].
• The results show that the tail of the long splice form a of Dsc, but not its shorter splice form b, contains sufficient information to recruit desmoplakin and plakoglobin to connexon membrane paracrystals (gap junctions) and to form a novel kind of plaque at which cytokeratin IFs attach [8].
• We have used sucrose gradient fractionation and chemical cross-linking to study the first step in gap junction assembly, oligomerization of Cx43 monomers into connexon channels [9].
• Differences between liver gap junction protein and lens MIP 26 from rat: implications for tissue specificity of gap junctions [10].
• All these synapses require the gap junction protein connexin36 (Cx36) for robust electrical coupling [11].

Chemical compound and disease context of Gap Junctions

• Most neoplastic cells, including C6 gliomas, express less connexins and have fewer gap junctions, reduced gap junctional intercellular communication, and increased growth rates compared with their nonneoplastic counterparts [12].
• Several studies have shown that cell damage signals are transmitted through gap junctions when cells are irradiated or when cells bearing the herpes simplex virus-thymidine kinase (HSV-TK) gene are treated with ganciclovir [13].
• Exposure to PGE2 and PGE1, promoters of bone resorption, rapidly (within 20 min) converted the osteoblasts from a flattened to a stellate shape (shape change), and markedly increased the appearance of intercellular (gap) junctions within 10 min [14].
• We determined the effect of flufenamic acid (FFA) and related derivatives on gap junction channel currents, applying the dual whole-cell patch-clamp technique to pairs of N2A neuroblastoma cells transfected with various connexins [15].
• Inclusion of a gap junction uncoupler (1 mM heptanol) in the injury solution narrowed the functional border and sharply increased the number of ectopic foci and the incidence of reperfusion arrhythmias [16].

Biological context of Gap Junctions

• We used polymerase chain reaction amplification and cDNA library screening to clone DNA encoding a human gap junction protein, connexin37 (Cx37) [17].
• Signaling through gap junction channels contributes to the homeostasis of the exocrine pancreas by coordinating acinar cell activity within an acinus [18].
• The sleep-inducing lipid oleamide deconvolutes gap junction communication and calcium wave transmission in glial cells [19].
• Transfection of Cx45tr and Cx45 had different effects in ROS cells, consistent with a role of the carboxyl-terminal domain of Cx45 in determining gap junction permeability or interactions between connexins [20].
• Ser364 of connexin43 and the upregulation of gap junction assembly by cAMP [21].

Anatomical context of Gap Junctions

• Connexin43 (Cx43) is an integral plasma membrane protein that forms gap junctions between vertebrate cells [9].
• Inhibition by anandamide of gap junctions and intercellular calcium signalling in striatal astrocytes [22].
• Our data suggest that Kcc4 is important for K(+) recycling() by siphoning K(+) ions after their exit from outer hair cells into supporting Deiters' cells, where K(+) enters the gap junction pathway [23].
• The development of gap junctions between insulin-containing B cells was quantitatively analyzed in islets of Langerhans isolated from rats treated with the sulfonylurea glibenclamid for 1, 2, or 7 days [24].
• We studied the potential role of the Wnt family of secreted polypeptides as regulators of Cx43 expression and gap junction channel function in dissociated myocytes and intact hearts [25].

Associations of Gap Junctions with chemical compounds

• Identification of a proline residue as a transduction element involved in voltage gating of gap junctions [26].
• Vitamin E supplementation above the deficient plasma levels of these infants suppresses gap junction formation and clinically reduces the severity without altering the total incidence of ROP [27].
• We found that neurobiotin (relative molecular mass, 286) passed easily through both types of gap junctions, but that biotin-X cadaverine (relative molecular mass, 442) passed through AII/bipolar cell gap junctions poorly compared to AII/AII gap junctions [28].
• The gap junction blocker octanol attenuated the neuronal response, which suggests that the astrocytic-neuronal signaling is mediated through intercellular connections rather than synaptically [29].
• NMDA receptors regulate developmental gap junction uncoupling via CREB signaling [30].

Gene context of Gap Junctions

• Cell to cell signaling, mediated by Cx43 gap junctions, was critical for normal osteogenesis, craniofacial development, and osteoblastic function [31].
• Gap junctions in rodent lens fibers contain two known intercellular channel-forming proteins, connexin50 (Cx50) and Cx46 [32].
• Subtractive hybridization, selecting for mRNAs expressed in normal human mammary epithelial cells (NMECs) but not in mammary tumor cell lines (TMECs), led to the cloning of the human gap junction gene connexin 26 (Cx26), identified by its sequence similarity to the rat gene [33].
• Sequence and tissue distribution of a second protein of hepatic gap junctions, Cx26, as deduced from its cDNA [34].
• In contrast, the Na-Pi cotransporter Npt2b, and the gap junction component connexin 32, usually expressed in secretory epithelia, were undetectable in PrlR- and Stat5-null mice [35].

Analytical, diagnostic and therapeutic context of Gap Junctions

• Confocal laser scanning microscopy revealed the presence of connexin43, a major constituent of the gap junction, at the donor-host cardiomyocyte border [36].
• Indirect immunofluorescence analyses showed that intact human and bovine adreno-cortical tissue as well as HAC and BAC in culture expressed the gap junction protein connexin43 (also termed alpha 1 connexin) [37].
• Both immunofluorescence microscopy and SDS PAGE reveal an abundance of MP70 in the lens outer cortex that coincides with a high frequency of fiber gap junctions in the same region [38].
• The in situ distribution of the 26-kdalton Main Intrinsic Polypeptide (MIP or MP 26), a putative gap junction protein in ocular lens fibers, was defined at the electron microscope level using indirect immunoferritin labeling of ultrathin frozen sections of rat lens [39].
• The mRNA and protein expression of alpha 1 (connexin 43), beta 1 (connexin 32), and beta 2 (connexin 26) gap junction genes were examined in the regenerating rat liver after 70% partial hepatectomy (PH) [40].

References