title: Activation of the Caenorhabditis elegans Degenerin Channel by Shear Stress Requires the MEC-10 Subunit.
abstract: Mechanotransduction in Caenorhabditis elegans touch receptor neurons is mediated by an ion channel formed by MEC-4, MEC-10, and accessory proteins. To define the role of these subunits in the channel's response to mechanical force, we expressed degenerin channels comprising MEC-4 and MEC-10 in Xenopus oocytes and examined their response to laminar shear stress (LSS). Shear stress evoked a rapid increase in whole cell currents in oocytes expressing degenerin channels as well as channels with a MEC-4 degenerin mutation (MEC-4d), suggesting that C. elegans degenerin channels are sensitive to LSS. MEC-10 is required for a robust LSS response as the response was largely blunted in oocytes expressing homomeric MEC-4 or MEC-4d channels. We examined a series of MEC-10/MEC-4 chimeras to identify specific domains (amino terminus, first transmembrane domain, and extracellular domain) and sites (residues 130-132 and 134-137) within MEC-10 that are required for a robust response to shear stress. In addition, the LSS response was largely abolished by MEC-10 mutations encoded by a touch-insensitive mec-10 allele, providing a correlation between the channel's responses to two different mechanical forces. Our findings suggest that MEC-10 has an important role in the channel's response to mechanical forces.
authors.affiliation: Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261.
authors.forename: Shujie
authors.initials: S
authors.lastname: Shi
authors.affiliation: Department of Pediatrics, University of Pittsburgh, Pittsburgh, Pennsylvania 15261.
authors.forename: Cliff J
authors.initials: CJ
authors.lastname: Luke
authors.affiliation: Department of Pediatrics, University of Pittsburgh, Pittsburgh, Pennsylvania 15261.
authors.forename: Mark T
authors.initials: MT
authors.lastname: Miedel
authors.affiliation: Department of Pediatrics, University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261.
authors.forename: Gary A
authors.initials: GA
authors.lastname: Silverman
authors.affiliation: Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261. Electronic address: kleyman@pitt.edu.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Kleyman
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D013314:Stress, Mechanical; D014981:Xenopus
chemical_list: D029742:Caenorhabditis elegans Proteins; C094927:Deg-1 protein, C elegans; D008565:Membrane Proteins; C085942:MEC-10 protein, C elegans
keywords: Caenorhabditis elegans (C. elegans); acid-sensing ion channel (ASIC); electrophysiology; epithelial sodium channel (ENaC); mechanotransduction; shear stress