RhoA Interaction with Inositol 1,4,5-Trisphosphate Receptor and Transient Receptor Potential Channel-1 Regulates Ca2+ Entry

• Published in: The Journal of biological chemistry Vol. 278; no. 35; pp. 33492 - 33500
• Main Authors: Mehta, Dolly, Ahmmed, Gias U., Paria, Biman C., Holinstat, Michael, Voyno-Yasenetskaya, Tatyana, Tiruppathi, Chinnaswamy, Minshall, Richard D., Malik, Asrar B.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 29.08.2003; American Society for Biochemistry and Molecular Biology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M302401200

We tested the hypothesis that RhoA, a monomeric GTP-binding protein, induces association of inositol trisphosphate receptor (IP3R) with transient receptor potential channel (TRPC1), and thereby activates store depletion-induced Ca2+ entry in endothelial cells. We showed that RhoA upon activation with thrombin associated with both IP3R and TRPC1. Thrombin also induced translocation of a complex consisting of Rho, IP3R, and TRPC1 to the plasma membrane. IP3R and TRPC1 translocation and association required Rho activation because the response was not seen in C3 transferase (C3)-treated cells. Rho function inhibition using Rho dominant-negative mutant or C3 dampened Ca2+ entry regardless of whether Ca2+ stores were emptied by thrombin, thapsigargin, or inositol trisphosphate. Rho-induced association of IP3R with TRPC1 was dependent on actin filament polymerization because latrunculin (which inhibits actin polymerization) prevented both the association and Ca2+ entry. We also showed that thrombin produced a sustained Rho-dependent increase in cytosolic Ca2+ concentration [Ca2+] i in endothelial cells overexpressing TRPC1. We further showed that Rho-activated Ca2+ entry via TRPC1 is important in the mechanism of the thrombin-induced increase in endothelial permeability. In summary, Rho activation signals interaction of IP3R with TRPC1 at the plasma membrane of endothelial cells, and triggers Ca2+ entry following store depletion and the resultant increase in endothelial permeability.