title: Gs cascade regulates canonical transient receptor potential 5 (TRPC5) through cAMP mediated intracellular Ca2+ release and ion channel trafficking.
abstract: Canonical transient receptor potential (TRPC) channels are Ca(2+)-permeable, non-selective cation channels those are widely expressed in mammalian cells. Various molecules have been found to regulate TRPC both in vivo and in vitro, but it is unclear how heterotrimeric G proteins transmit external stimuli to regulate the activity of TRPC5. Here, we demonstrated that TRPC5 was potentiated by the Gα(s) regulatory pathway. Whole-cell TRPC5 current was significantly increased by β-adrenergic receptor agonist, isoproterenol (ISO, 246±36%, n=6), an activator of the adenylate cyclase, forskolin (FSK, 273±6%, n=5), or a membrane permeable cAMP analogue, 8-Br-cAMP (251±63%, n=7). In addition, robust Ca(2+) transient induced by isoproterenol was observed utilizing a Ca(2+) imaging technique. When intracellular [Ca(2+)](i) was buffered to 50nM, cAMP-induced potentiation was attenuated. We also found that the Ca(2+) release is mediated by IP(3) since intracellular IP(3) infusion attenuated the potentiation of TRPC5 by Gα(s) cascade. Finally, we identified that the membrane localization of TRPC5 was significantly increased by ISO (155±17%, n=3), FSK (172±39%, n=3) or 8-Br-cAMP (216±59%, n=3). In conclusion, these results suggest that the Gα(s)-cAMP pathway potentiates the activity of TRPC5 via facilitating intracellular Ca(2+) dynamics and increasing channel trafficking to the plasma membrane.
authors.affiliation: Department of Physiology and Institute of Dermatological Science, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Chansik
authors.initials: C
authors.lastname: Hong
authors.forename: Jinsung
authors.initials: J
authors.lastname: Kim
authors.forename: Jae-Pyo
authors.initials: JP
authors.lastname: Jeon
authors.forename: Jinhong
authors.initials: J
authors.lastname: Wie
authors.forename: Misun
authors.initials: M
authors.lastname: Kwak
authors.forename: Kotdaji
authors.initials: K
authors.lastname: Ha
authors.forename: Hana
authors.initials: H
authors.lastname: Kim
authors.forename: Jongyun
authors.initials: J
authors.lastname: Myeong
authors.forename: Sung Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Ju-Hong
authors.initials: JH
authors.lastname: Jeon
authors.forename: Insuk
authors.initials: I
authors.lastname: So
mesh_terms: D018663:Adrenergic Agents / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D021381:Protein Transport; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D050052:TRPC Cation Channels / Q000378:metabolism*
chemical_list: D018663:Adrenergic Agents; D011943:Receptors, Adrenergic, beta; D050052:TRPC Cation Channels; C491780:TRPC5 protein, human; D000242:Cyclic AMP; D019205:GTP-Binding Protein alpha Subunits, Gs; D007545:Isoproterenol; D002118:Calcium