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Gap junctions are formed by a family of homologous proteins termed connexins. Their channels are dodecamers, and homomeric forms differ in their properties with respect to control by voltage and other gating stimuli. We report here the properties of coupling from expression of connexin complementary RNAs (cRNAs; sense to mRNA, antisense to cDNA) in Xenopus(More)
The importance of electrical and molecular signaling through connexin (Cx) channels is now widely recognized. The transfer of ions and other small molecules between adjacent cells is regulated by multiple stimuli, including voltage. Indeed, Cx channels typically exhibit complex voltage sensitivity. Most channels are sensitive to the voltage difference(More)
Hexamers of connexins (Cxs) form hemichannels that dock tightly in series via their extracellular domains to give rise to gap junction channels. Here we examined the ability of a variety of C-terminal Cx32 mutations, most of which have been identified in X-linked Charcot-Marie-Tooth disease, to form hemichannels and to complete gap junction channels using(More)
In addition to forming gap-junction channels, a subset of connexins (Cxs) also form functional hemichannels. Most hemichannels are activated by depolarization, and opening depends critically on the external Ca2+ concentration. Here we describe the mechanisms of action and the structural determinants underlying the Ca2+ regulation of Cx32 hemichannels. At(More)
Mutations of connexin-26 (Cx26) cause nonsyndromic hearing loss and other syndromes affecting ectoderm-derived tissues. While the exact mechanisms underlying these diseases remain elusive, Cx's are generally considered to mediate cell-to-cell communication by forming gap junction channels. We show here that unlike rat Cx26, human and sheep Cx26 form(More)
The mechanisms mediating intrinsic and entrained CA1 pyramidal neuron rhythmic membrane potential oscillations were investigated in rat hippocampal slices. Intrinsic oscillations (6-14 Hz, < 10 mV) were evoked by long duration (2 s), depolarizing current pulses in 42% of the cells. Oscillations were also evoked by imposing sinusoidal transmembrane currents(More)
Gap junctions composed of connexin-45 (Cx45) homologs from four species, zebrafish, chicken, mouse, and human, were expressed in pairs of Xenopus oocytes. The macroscopic conductance (gj) of all Cx45 junctions was modulated by transjunctional voltage (Vj) and by the inside-outside voltage (Vm), and the modulation was species specific. Although their gating(More)
PURPOSE To identify, clone molecularly, characterize immunochemically, and express functionally a bovine lens gap junction protein (connexin). METHODS The methods used were polymerase chain reaction, genomic cloning, RNA and DNA blotting, bacterial expression of a fusion protein, immunoblotting, alkaline phosphatase treatment, Xenopus oocyte expression,(More)
Neurotransmission through electrical synapses plays an important role in the spike synchrony among neurons and oscillation of neuronal networks. Indeed, electrical transmission has been implicated in the hypersynchronous electrical activity of epilepsy. We have investigated the influence of intracellular pH on the strength of electrical coupling mediated by(More)