title: Heteromeric assembly of acid-sensitive ion channel and epithelial sodium channel subunits.
abstract: Amiloride-sensitive ion channels are formed from homo- or heteromeric combinations of subunits from the epithelial Na+ channel (ENaC)/degenerin superfamily, which also includes the acid-sensitive ion channel (ASIC) family. These channel subunits share sequence homology and topology. In this study, we have demonstrated, using confocal fluorescence resonance energy transfer microscopy and co-immunoprecipitation, that ASIC and ENaC subunits are capable of forming cross-clade intermolecular interactions. We have also shown that combinations of ASIC1 with ENaC subunits exhibit novel electrophysiological characteristics compared with ASIC1 alone. The results of this study suggest that heteromeric complexes of ASIC and ENaC subunits may underlie the diversity of amiloride-sensitive cation conductances observed in a wide variety of tissues and cell types where co-expression of ASIC and ENaC subunits has been observed.
authors.affiliation: Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Meltzer
authors.forename: Niren
authors.initials: N
authors.lastname: Kapoor
authors.forename: Yawar J
authors.initials: YJ
authors.lastname: Qadri
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Anderson
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Fuller
authors.forename: Dale J
authors.initials: DJ
authors.lastname: Benos
mesh_terms: D062565:Acid Sensing Ion Channels; D000818:Animals; D016466:CHO Cells; D002412:Cations / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D053503:Epithelial Sodium Channels / Q000235:genetics / Q000378:metabolism*; D031541:Fluorescence Resonance Energy Transfer; D015870:Gene Expression; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D018613:Microscopy, Confocal; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009928:Organ Specificity / Q000502:physiology; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015222:Sodium Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: C568266:ASIC1 protein, human; D062565:Acid Sensing Ion Channels; D002412:Cations; D053503:Epithelial Sodium Channels; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D021122:Protein Subunits; D015222:Sodium Channels