TRPC1 and Orai1 interact with STIM1 and mediate capacitative Ca(2+) entry caused by acute hypoxia in mouse pulmonary arterial smooth muscle cells.

Previous studies in pulmonary artery smooth muscle cells (PASMCs) showed that acute hypoxia activates capacitative Ca(2+) entry (CCE) but the molecular candidate(s) mediating CCE caused by acute hypoxia remain unclear. The present study aimed to determine if transient receptor potential canonical 1 (TRPC1) and Orai1 interact with stromal interacting molecule 1 (STIM1) and mediate CCE caused by acute hypoxia in mouse PASMCs. In primary cultured PASMCs loaded with fura-2, acute hypoxia caused a transient followed by a sustained rise in intracellular Ca(2+) concentration ([Ca(2+)](i)).