title: Regulation of the cystic fibrosis transmembrane conductance regulator anion channel by tyrosine phosphorylation.
abstract: The cystic fibrosis transmembrane conductance regulator (CFTR) channel is activated by PKA phosphorylation of a regulatory domain that interacts dynamically with multiple CFTR domains and with other proteins. The large number of consensus sequences for phosphorylation by PKA has naturally focused most attention on regulation by this kinase. We report here that human CFTR is also phosphorylated by the tyrosine kinases p60c-Src (proto-oncogene tyrosine-protein kinase) and the proline-rich tyrosine kinase 2 (Pyk2), and they can also cause robust activation of quiescent CFTR channels. In excised patch-clamp experiments, CFTR activity during exposure to Src or Pyk2 reached ∼80% of that stimulated by PKA. Exposure to PKA after Src or Pyk2 caused a further increase to the level induced by PKA alone, implying a common limiting step. Channels became spontaneously active when v-Src or the catalytic domain of Pyk2 was coexpressed with CFTR and were further stimulated by the tyrosine phosphatase inhibitor dephostatin. Exogenous Src also activated 15SA-CFTR, a variant that lacks 15 potential PKA sites and has little response to PKA. PKA-independent activation by tyrosine phosphorylation has implications for the mechanism of regulation by the R domain and for the physiologic functions of CFTR.
authors.affiliation: *Department of Physiology and Cystic Fibrosis Translational Research Centre, McGill University, Montreal, Quebec, Canada; Department of Biochemistry and Biophysics and Cystic Fibrosis Research Center, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA; and Research Institute of the McGill University Hospital Centre, Montreal, Quebec, Canada arnaud.billet@mcgill.ca.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Billet
authors.affiliation: *Department of Physiology and Cystic Fibrosis Translational Research Centre, McGill University, Montreal, Quebec, Canada; Department of Biochemistry and Biophysics and Cystic Fibrosis Research Center, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA; and Research Institute of the McGill University Hospital Centre, Montreal, Quebec, Canada.
authors.forename: Yanlin
authors.initials: Y
authors.lastname: Jia
authors.affiliation: *Department of Physiology and Cystic Fibrosis Translational Research Centre, McGill University, Montreal, Quebec, Canada; Department of Biochemistry and Biophysics and Cystic Fibrosis Research Center, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA; and Research Institute of the McGill University Hospital Centre, Montreal, Quebec, Canada.
authors.forename: Tim
authors.initials: T
authors.lastname: Jensen
authors.affiliation: *Department of Physiology and Cystic Fibrosis Translational Research Centre, McGill University, Montreal, Quebec, Canada; Department of Biochemistry and Biophysics and Cystic Fibrosis Research Center, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA; and Research Institute of the McGill University Hospital Centre, Montreal, Quebec, Canada.
authors.forename: John R
authors.initials: JR
authors.lastname: Riordan
authors.affiliation: *Department of Physiology and Cystic Fibrosis Translational Research Centre, McGill University, Montreal, Quebec, Canada; Department of Biochemistry and Biophysics and Cystic Fibrosis Research Center, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA; and Research Institute of the McGill University Hospital Centre, Montreal, Quebec, Canada.
authors.forename: John W
authors.initials: JW
authors.lastname: Hanrahan
mesh_terms: D000818:Animals; D000081247:CSK Tyrosine-Protein Kinase; D002460:Cell Line; D006224:Cricetinae; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000378:metabolism*; D051418:Focal Adhesion Kinase 2 / Q000235:genetics / Q000378:metabolism; D006801:Humans; D010766:Phosphorylation / Q000502:physiology; D017434:Protein Structure, Tertiary; D000090063:Proto-Oncogene Mas; D014443:Tyrosine / Q000235:genetics / Q000378:metabolism; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: C505032:CFTR protein, human; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D014443:Tyrosine; D000081247:CSK Tyrosine-Protein Kinase; D051418:Focal Adhesion Kinase 2; D019061:src-Family Kinases; C000631346:CSK protein, human; D017868:Cyclic AMP-Dependent Protein Kinases
keywords: Pyk2; R domain; Src