title: Intermolecular Interactions in the TMEM16A Dimer Controlling Channel Activity.
abstract: TMEM16A and TMEM16B are plasma membrane proteins with Ca2+-dependent Cl-channel function. By replacing the carboxy-terminus of TMEM16A with the equivalent region of TMEM16B, we obtained channels with potentiation of channel activity. Progressive shortening of the chimeric region restricted the "activating domain" to a short sequence close to the last transmembrane domain and led to TMEM16A channels with high activity at very low intracellular Ca2+concentrations. To elucidate the molecular mechanism underlying this effect, we carried out experiments based on double chimeras, Forster resonance energy transfer, and intermolecular cross-linking. We also modeled TMEM16A structure using the Nectria haematococca TMEM16 protein as template. Our results indicate that the enhanced activity in chimeric channels is due to altered interaction between the carboxy-terminus and the first intracellular loop in the TMEM16A homo-dimer. Mimicking this perturbation with a small molecule could be the basis for a pharmacological stimulation of TMEM16A-dependent Cl-transport.
authors.affiliation: U.O.C. Genetica Medica, Istituto Giannina Gaslini, Genova, Italy.|Telethon Institute for Genetics and Medicine (Tigem), Pozzuoli, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Scudieri
authors.affiliation: Telethon Institute for Genetics and Medicine (Tigem), Pozzuoli, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Musante
authors.affiliation: U.O.C. Genetica Medica, Istituto Giannina Gaslini, Genova, Italy.
authors.forename: Ambra
authors.initials: A
authors.lastname: Gianotti
authors.affiliation: Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy.
authors.forename: Oscar
authors.initials: O
authors.lastname: Moran
authors.affiliation: U.O.C. Genetica Medica, Istituto Giannina Gaslini, Genova, Italy.|Telethon Institute for Genetics and Medicine (Tigem), Pozzuoli, Italy.
authors.forename: Luis J V
authors.initials: LJ
authors.lastname: Galietta
mesh_terms: D000075369:Anoctamin-1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D017136:Ion Transport; D008958:Models, Molecular; D009363:Neoplasm Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000072417:Protein Domains; D055503:Protein Multimerization
chemical_list: C476213:ANO1 protein, human; D000075369:Anoctamin-1; D002712:Chlorides; D009363:Neoplasm Proteins; D002118:Calcium