title: Desensitization of canonical transient receptor potential channel 5 by protein kinase C.
abstract: The classic type of transient receptor potential channel (TRPC) is a molecular candidate for Ca(2+)-permeable cation channel in mammalian cells. TRPC5 is desensitized rapidly after activation by G protein-coupled receptor. Herein we report our investigation into the desensitization of mTRPC5 and localization of the molecular determinants of this desensitization using mutagenesis. TRPC5 was initially activated by muscarinic stimulation using 100 microM carbachol (CCh) and then decayed rapidly even in the presence of CCh (desensitization). Increased EGTA or omission of MgATP in the pipette solution slowed the rate of this desensitization. The protein kinase C (PKC) inhibitors, 1 microM chelerythrine, 100 nM GF109203X, or PKC peptide inhibitor (19-36), inhibited this desensitization of TRPC5 activated by 100 microM CCh. When TRPC5 current was activated by intracellular GTPgammaS, PKC inhibitors prevented TRPC5 desensitization and the mutation of TRPC5 T972 to alanine slowed the desensitization process dramatically. We conclude that the desensitization of TRPC5 occurs via PKC phosphorylation and suggest that threonine at residue 972 of mouse TRPC5 might be required for its phosphorylation by PKC.
authors.affiliation: Dept. of Physiology and Biophysics, Seoul National University College of Medicine, Chongno-Gu, Seoul 110-799, Korea.
authors.forename: Mei Hong
authors.initials: MH
authors.lastname: Zhu
authors.forename: MeeRee
authors.initials: M
authors.lastname: Chae
authors.forename: Hyun Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Young Mee
authors.initials: YM
authors.lastname: Lee
authors.forename: Min Ji
authors.initials: MJ
authors.lastname: Kim
authors.forename: Nan Ge
authors.initials: NG
authors.lastname: Jin
authors.forename: Dong Ki
authors.initials: DK
authors.lastname: Yang
authors.forename: Insuk
authors.initials: I
authors.lastname: So
authors.forename: Ki Whan
authors.initials: KW
authors.lastname: Kim
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology; D027682:Cation Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002614:Chelating Agents / Q000494:pharmacology; D018679:Cholinergic Agonists / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D007668:Kidney / Q000166:cytology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D051379:Mice; D016296:Mutagenesis / Q000502:physiology; D018408:Patch-Clamp Techniques; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D050052:TRPC Cation Channels
chemical_list: D015220:Calcium Channels; D027682:Cation Transport Proteins; D002614:Chelating Agents; D018679:Cholinergic Agonists; D004791:Enzyme Inhibitors; D050052:TRPC Cation Channels; C112021:Trpc5 protein, mouse; D004533:Egtazic Acid; D000255:Adenosine Triphosphate; D002217:Carbachol; D011493:Protein Kinase C; D002118:Calcium