Referenced in: none

Automatically associated channels: Slo1 , TRP , TRPC , TRPC1 , TRPV , TRPV4

Title: Heteromeric TRPV4-C1 channels contribute to store-operated Ca(2+) entry in vascular endothelial cells.

Authors: Xin Ma, Kwong-Tai Cheng, Ching-On Wong, Roger G O'neil, Lutz Birnbaumer, Indu S Ambudkar, Xiaoqiang Yao

Journal, date & volume: Cell Calcium, 2011 Dec , 50, 502-9

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/21930300

Abstract
There is controversy as to whether TRP channels participate in mediating store-operated current (I(SOC)) and store-operated Ca(2+) entry (SOCE). Our recent study has demonstrated that TRPC1 forms heteromeric channels with TRPV4 in vascular endothelial cells and that Ca(2+) store depletion enhances the vesicle trafficking of heteromeric TRPV4-C1 channels, causing insertion of more channels into the plasma membrane in vascular endothelial cells. In the present study, we determined whether the enhanced TRPV4-C1 insertion to the plasma membrane could contribute to SOCE and I(SOC). We found that thapsigargin-induced SOCE was much lower in aortic endothelial cells derived from trpv4(-/-) or trpc1(-/-) knockout mice when compared to that of wild-type mice. In human umbilical vein endothelial cells (HUVECs), thapsigargin-induced SOCE was markedly reduced by knocking down the expression of TRPC1 and/or TRPV4 with respective siRNAs. Brefeldin A, a blocker of vesicular translocation, inhibited the SOCE. These results suggest that an enhanced vesicular trafficking of heteromeric TRPV4-C1 channels contributes to SOCE in vascular endothelial cells. Vascular tension studies suggest that such an enhanced trafficking of TRPV4-C1 channels may play a role in thapsigargin-induced vascular relaxation in rat small mesenteric arteries.