DEG/ENaC channels: a touchy superfamily that watches its salt.
To the surprise of many, studies of molecular mechanisms of touch transduction and analyses of epithelial Na+ transport have converged to define a new class of ion channel subunits. Based on the names of the first two identified subfamilies, the Caenorhabditis elegans degenerins and the vertebrate epithelial amiloride-sensitive Na+ channel, this ion channel class is called the DEG/ENaC superfamily. Members of the DEG/ENaC superfamily have been found in nematodes, flies, snails, and vertebrates. Family members share common topology, such that they span the membrane twice and have intracellular N- and C-termini; a large extracellular loop includes a conserved cysteine-rich region. DEG/ENaC channels have been implicated a broad spectrum of cellular functions, including mechanosensation, proprioception, pain sensation, gametogenesis, and epithelial Na+ transport. These channels exhibit diverse gating properties, ranging from near constitutive opening to rapid inactivation. We discuss working understanding of DEG/ENaC functions, channel properties, structure/activity correlations and possible evolutionary relationship to other channel classes.
Mano
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Department of Molecular Biology and Biochemistry, Rutgers, State University of New Jersey, Piscataway 08854, USA.
Driscoll
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D062565:Acid Sensing Ion Channels; D000818:Animals; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins; D062626:Degenerin Sodium Channels; D004330:Drosophila; D053503:Epithelial Sodium Channels; D005718:Gametogenesis; D006801:Humans; D007473:Ion Channels / Q000502:physiology*; D008565:Membrane Proteins; D009410:Nerve Degeneration; D009419:Nerve Tissue Proteins / Q000502:physiology*; D009475:Neurons, Afferent; D015398:Signal Transduction; D012964:Sodium / Q000378:metabolism*; D015222:Sodium Channels / Q000502:physiology*
C568424:ASIC2 protein, human; D062565:Acid Sensing Ion Channels; D029742:Caenorhabditis elegans Proteins; D062626:Degenerin Sodium Channels; D053503:Epithelial Sodium Channels; C097095:FaNaCh protein, Helix aspersa; D007473:Ion Channels; C115871:Mec-4 protein, C elegans; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D015222:Sodium Channels; D012964:Sodium