title: Secreted CLCA1 modulates TMEM16A to activate Ca(2+)-dependent chloride currents in human cells.
abstract: Calcium-activated chloride channel regulator 1 (CLCA1) activates calcium-dependent chloride currents; neither the target, nor mechanism, is known. We demonstrate that secreted CLCA1 activates calcium-dependent chloride currents in HEK293T cells in a paracrine fashion, and endogenous TMEM16A/Anoctamin1 conducts the currents. Exposure to exogenous CLCA1 increases cell surface levels of TMEM16A and cellular binding experiments indicate CLCA1 engages TMEM16A on the surface of these cells. Altogether, our data suggest that CLCA1 stabilizes TMEM16A on the cell surface, thus increasing surface expression, which results in increased calcium-dependent chloride currents. Our results identify the first Cl(-) channel target of the CLCA family of proteins and establish CLCA1 as the first secreted direct modifier of TMEM16A activity, delineating a unique mechanism to increase currents. These results suggest cooperative roles for CLCA and TMEM16 proteins in influencing the physiology of multiple tissues, and the pathology of multiple diseases, including asthma, COPD, cystic fibrosis, and certain cancers.
authors.affiliation: Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, United States.
authors.forename: Monica
authors.initials: M
authors.lastname: Sala-Rabanal
authors.affiliation: Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St Louis, United States.
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Yurtsever
authors.affiliation: Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, United States.
authors.forename: Colin G
authors.initials: CG
authors.lastname: Nichols
authors.affiliation: Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, United States.
authors.forename: Tom J
authors.initials: TJ
authors.lastname: Brett
mesh_terms: D000075369:Anoctamin-1; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D018118:Chloride Channels / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D002712:Chlorides / Q000378:metabolism / Q000494:pharmacology; D057809:HEK293 Cells; D006801:Humans; D015640:Ion Channel Gating; D008564:Membrane Potentials / Q000187:drug effects; D018613:Microscopy, Confocal; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D019899:Paracrine Communication / Q000187:drug effects; D018408:Patch-Clamp Techniques; D011485:Protein Binding; D034622:RNA Interference
chemical_list: C476213:ANO1 protein, human; D000075369:Anoctamin-1; C492109:CLCA1 protein, human; D018118:Chloride Channels; D002712:Chlorides; D009363:Neoplasm Proteins; D002118:Calcium
keywords: biophysics; calcium activated chloride channels; cell biology; chronic inflammatory airway disease; human; ion channel regulation; structural biology