Isoform-Selective Physical Coupling of TRPC3 Channels to IP3 Receptors in Smooth Muscle Cells Regulates Arterial Contractility

摘要: Rationale: Inositol 1,4,5-trisphosphate (IP 3 )-induced vasoconstriction can occur independently of intracellular Ca 2+ release and via IP receptor R) canonical transient potential (TRPC) channel activation, but functional signaling mechanisms mediating this effect are unclear. Objectives: Study by which Rs stimulate TRPC channels in myocytes resistance-size cerebral arteries. Methods Results: Immunofluorescence resonance energy transfer (immuno-FRET) microscopy using isoform-selective antibodies indicated that endogenous type 1 R1) close spatial proximity to TRPC3, distant from TRPC6 or TRPM4 arterial myocytes. Endothelin-1 (ET-1), a phospholipase C–coupled agonist, elevated immuno-FRET between R1 not TRPM4. TRPC6, coimmunoprecipitated with R1. TRPC3 selectively inhibited recombinant channels, only the antibody blocked -induced nonselective cation current ( I Cat ) knockdown attenuated ET-1 vasoconstriction, whereas had no effect. did alter total plasma membrane-localized as determined surface biotinylation. RT-PCR demonstrated C-terminal calmodulin R binding (CIRB) domains present myocyte channels. A peptide corresponding N-terminal region interact activated . CIRB domain - ET-1–induced activation vasoconstriction. Conclusions: stimulates direct coupling membrane-resident myocytes, leading Close establishes interaction.