Polycystin-2 (TRPP2) is a Ca2+ permeable nonselective cationic channel essential for maintaining physiological function in live cells. Stromal interaction molecule 1 (STIM1) is an important Ca2+ sensor in store-operated Ca2+ entry (SOCE). Both TRPP2 and STIM1 are expressed in endoplasmic reticular membrane and participate in Ca2+ signaling, suggesting a physical interaction and functional synergism. We performed co-localization, co-immunoprecipitation, and fluorescence resonance energy transfer assay to identify the interactions of TRPP2 and STIM1 in transfected HEK293 cells and native vascular smooth muscle cells (VSMCs). The function of the TRPP2-STIM1 complex in thapsigargin (TG) or adenosine triphosphate (ATP)-induced SOCE was explored using specific small interfering RNA (siRNA). Further, we created TRPP2 conditional knockout (CKO) mouse to investigate the functional role of TRPP2 in agonist-induced vessel contraction. TRPP2 and STIM1 form a complex in transfected HEK293 cells and native VSMCs. Genetic manipulations with TRPP2 siRNA, dominant negative TRPP2 or STIM1 siRNA significantly suppressed ATP and TG-induced intracellular Ca2+ release and SOCE in HEK293 cells. Inositol triphosphate receptor inhibitor 2-aminoethyl diphenylborinate (2APB) abolished ATP-induced Ca2+ release and SOCE in HEK293 cells. In addition, TRPP2 and STIM1 knockdown significantly inhibited ATP- and TG-induced STIM1 puncta formation and SOCE in VSMCs. Importantly, knockdown of TRPP2 and STIM1 or conditional knockout TRPP2 markedly suppressed agonist-induced mouse aorta contraction. Our data indicate that TRPP2 and STIM1 are physically associated and form a functional complex to regulate agonist-induced intracellular Ca2+ mobilization, SOCE and blood vessel tone.

中文翻译：

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TRPP2 和 STIM1 形成一个微域来调节存储操作的 Ca2+ 进入和血管张力。

Polycystin-2 (TRPP2) 是一种 Ca2+ 可渗透的非选择性阳离子通道，对于维持活细胞的生理功能至关重要。基质相互作用分子 1 (STIM1) 是存储操作的 Ca2+ 进入 (SOCE) 中重要的 Ca2+ 传感器。TRPP2 和 STIM1 在内质网膜中表达并参与 Ca2+ 信号传导，表明存在物理相互作用和功能协同作用。我们进行了共定位、共免疫沉淀和荧光共振能量转移测定，以确定转染的 HEK293 细胞和天然血管平滑肌细胞 (VSMC) 中 TRPP2 和 STIM1 的相互作用。使用特定的小干扰 RNA (siRNA) 探索了 TRPP2-STIM1 复合物在毒胡萝卜素 (TG) 或三磷酸腺苷 (ATP) 诱导的 SOCE 中的功能。更远，我们创建了 TRPP2 条件性敲除 (CKO) 小鼠来研究 TRPP2 在激动剂诱导的血管收缩中的功能作用。TRPP2 和 STIM1 在转染的 HEK293 细胞和天然 VSMC 中形成复合物。使用 TRPP2 siRNA、显性负性 TRPP2 或 STIM1 siRNA 进行遗传操作可显着抑制 HEK293 细胞中 ATP 和 TG 诱导的细胞内 Ca2+ 释放和 SOCE。三磷酸肌醇受体抑制剂 2-氨基乙基二苯基硼酸酯 (2APB) 消除了 HEK293 细胞中 ATP 诱导的 Ca2+ 释放和 SOCE。此外，TRPP2 和 STIM1 敲低显着抑制了 VSMC 中 ATP 和 TG 诱导的 STIM1 斑点形成和 SOCE。重要的是，敲除 TRPP2 和 STIM1 或有条件敲除 TRPP2 显着抑制激动剂诱导的小鼠主动脉收缩。