title: Functional regulation of transient receptor potential canonical 7 by cGMP-dependent protein kinase Iα.
abstract: The cGMP/cGMP-dependent protein kinase (cGK) signaling pathway is implicated in the functional regulation of intracellular calcium levels. In the present study, we investigated the regulation of transient receptor potential canonical 7 (TRPC7) by the cGMP/cGK-I pathway. TRPC7 contains three putative cGK phosphorylation sites (Arg-Arg/Lys-Xaa-Ser/Thr). However, the role of cGK-I in the regulation of TRPC7 activity remains unclear. In vitro and in vivo kinase assays have revealed that cGK-Iα phosphorylates mouse TRPC7 but not mouse TRPC3. Site-directed mutagenesis analysis revealed that TRPC7 was phosphorylated by cGK-Iα at threonine 15. Phosphorylation of TRPC7 significantly suppressed carbachol-induced calcium influx and CREB phosphorylation. Furthermore, co-immunoprecipitation assay demonstrated that cGK-Iα interacted with the ankyrin repeat domain in the N terminus of TRPC7. cGK-Iβ also bound to TRPC7, while the type II regulatory subunit of cAMP-dependent protein kinase did not bind. These data indicate that cGK-Iα interacts with and phosphorylates TRPC7, contributing to the quick and accurate regulation of calcium influx and CREB phosphorylation.
authors.affiliation: Department of Biological Science and Technology, The University of Tokushima Graduate School, 2–1 Minamijosanjima, Tokushima, Japan. yuasa@bio.tokushima-u.ac.jp
authors.forename: Keizo
authors.initials: K
authors.lastname: Yuasa
authors.forename: Taito
authors.initials: T
authors.lastname: Matsuda
authors.forename: Akihiko
authors.initials: A
authors.lastname: Tsuji
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D020013:Calcium Signaling; D002217:Carbachol / Q000494:pharmacology; D002522:Chlorocebus aethiops; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D062965:Cyclic GMP-Dependent Protein Kinase Type I; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism*; D057075:Enzyme Assays; D057809:HEK293 Cells; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: C115163:CREB1 protein, human; D017362:Cyclic AMP Response Element-Binding Protein; D007527:Isoenzymes; D011993:Recombinant Fusion Proteins; D050052:TRPC Cation Channels; C498501:TRPC7 protein, human; D002217:Carbachol; D062965:Cyclic GMP-Dependent Protein Kinase Type I; D017869:Cyclic GMP-Dependent Protein Kinases; C569718:PRKG1 protein, human; C569720:Prkg1 protein, mouse