RhoA interaction with inositol 1,4,5-trisphosphate receptor and transient receptor potential channel-1 regulates Ca2+ entry. Role in signaling increased endothelial permeability.
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.
Mesh Terms:
ADP Ribose Transferases, Actins, Botulinum Toxins, Calcium, Calcium Channels, Cells, Cultured, Electrophoresis, Polyacrylamide Gel, Electrophysiology, Endothelium, Vascular, Genes, Dominant, Humans, Inositol 1,4,5-Trisphosphate Receptors, Microscopy, Confocal, Models, Biological, Patch-Clamp Techniques, Precipitin Tests, Protein Binding, Protein Transport, Receptors, Cytoplasmic and Nuclear, Signal Transduction, TRPC Cation Channels, Thapsigargin, Thrombin, Time Factors, Transfection, rho GTP-Binding Proteins, rhoA GTP-Binding Protein
ADP Ribose Transferases, Actins, Botulinum Toxins, Calcium, Calcium Channels, Cells, Cultured, Electrophoresis, Polyacrylamide Gel, Electrophysiology, Endothelium, Vascular, Genes, Dominant, Humans, Inositol 1,4,5-Trisphosphate Receptors, Microscopy, Confocal, Models, Biological, Patch-Clamp Techniques, Precipitin Tests, Protein Binding, Protein Transport, Receptors, Cytoplasmic and Nuclear, Signal Transduction, TRPC Cation Channels, Thapsigargin, Thrombin, Time Factors, Transfection, rho GTP-Binding Proteins, rhoA GTP-Binding Protein
J. Biol. Chem.
Date: Aug. 29, 2003
PubMed ID: 12766172
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