Isoform-selective physical coupling of TRPC3 channels to IP3 receptors in smooth muscle cells regulates arterial contractility.
Isoform-selective physical coupling of TRPC3 channels to IP3 receptors in smooth muscle cells regulates arterial contractility.
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DOI：
10.1161/circresaha.110.216804
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发表时间：
2010-05-28
影响因子：
20.1
通讯作者：
Jaggar JH
中科院分区：
文献类型：
--
作者：
Adebiyi A;Zhao G;Narayanan D;Thomas-Gatewood CM;Bannister JP;Jaggar JH
肌醇1，4，5-三磷酸(IP3)引起的血管收缩作用不依赖于细胞内钙离子的释放，而是通过IP3受体(IP3R)和典型瞬时受体电位(TRPC)通道激活而发生的，但介导这一作用的功能信号机制尚不清楚。研究IP3Rs刺激阻力大小脑动脉心肌细胞TRPC通道的机制。免疫荧光共振能量转移显微镜观察发现，内源性1型IP3R(IP3R1)在空间上与TRPC3接近，但远离TRPC6或TRPM4通道。内皮素-1(ET-1)是一种磷脂酶C偶联受体激动剂，可促进IP3R1与TRPC3之间的免疫反应，但不能促进IP3R1与TRPC6或TRPM4之间的免疫反应。TRPC3与IP3R1共沉淀，而不是TRPC6。TRPC3和TRPC6抗体选择性抑制重组通道，但只有TRPC3抗体阻断IP3诱导的非选择性阳离子电流(ICAT)。TRPC3抑制IP3R1和TRPC3之间的免疫反应，IP3诱导的ICAT激活，ET-1和IP3诱导的血管收缩，而TRPC6通道阻断没有影响。ET-1不改变总TRPC3或质膜定位的TRPC3，通过表面生物素化来确定。RT-PCR结果表明，在心肌细胞TRPC3和TRPC6通道中存在钙调素和IP3R结合(CIRB)结构域。与IP3R N-末端区域相对应的肽，可以与激活ICAT的TRPC通道相互作用。TRPC3 CIRB结构域肽可减弱IP3和ET-1诱导的ICAT激活和血管收缩。IP3刺激IP3R1和膜上驻留的TRPC3通道之间的直接偶联，导致ICAT激活和血管收缩。IP3R1和TRPC3之间的紧密空间接近建立了这种异构体选择性的功能相互作用。
Inositol 1,4,5-trisphosphate (IP3)-induced vasoconstriction can occur independently of intracellular Ca2+ release and via IP3 receptor (IP3R) and canonical transient receptor potential (TRPC) channel activation, but functional signaling mechanisms mediating this effect are unclear. Study mechanisms by which IP3Rs stimulate TRPC channels in myocytes of resistance-size cerebral arteries. Immunofluorescence resonance energy transfer (immuno-FRET) microscopy using isoform-selective antibodies indicated that endogenous type 1 IP3Rs (IP3R1) are in close spatial proximity to TRPC3, but distant from TRPC6 or TRPM4 channels in arterial myocytes. Endothelin-1 (ET-1), a phospholipase C-coupled receptor agonist, elevated immuno-FRET between IP3R1 and TRPC3, but not between IP3R1 and TRPC6 or TRPM4. TRPC3, but not TRPC6, co-immunoprecipitated with IP3R1. TRPC3 and TRPC6 antibodies selectively inhibited recombinant channels, but only the TRPC3 antibody blocked IP3-induced non-selective cation current (ICat) in myocytes. TRPC3 knockdown attenuated immuno-FRET between IP3R1 and TRPC3, IP3-induced ICat activation, and ET-1 and IP3-induced vasoconstriction, whereas TRPC6 channel knockdown had no effect. ET-1 did not alter total or plasma membrane-localized TRPC3, as determined using surface biotinylation. RT-PCR demonstrated that C-terminal calmodulin and IP3R binding (CIRB) domains are present in myocyte TRPC3 and TRPC6 channels. A peptide corresponding to the IP3R N-terminal region that can interact with TRPC channels activated ICat. A TRPC3 CIRB domain peptide attenuated IP3- and ET-1-induced ICat activation and vasoconstriction. IP3 stimulates direct coupling between IP3R1 and membrane-resident TRPC3 channels in arterial myocytes, leading to ICat activation and vasoconstriction. Close spatial proximity between IP3R1 and TRPC3 establishes this isoform-selective functional interaction.