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.
Mehta
Dolly
D
Department of Pharmacology, College of Medicine, The University of Illinois, Chicago, Illinois 60612, USA. dmehta@uic.edu
Ahmmed
Gias U
GU
Paria
Biman C
BC
Holinstat
Michael
M
Voyno-Yasenetskaya
Tatyana
T
Tiruppathi
Chinnaswamy
C
Minshall
Richard D
RD
Malik
Asrar B
AB
D036002:ADP Ribose Transferases / Q000494:pharmacology; D000199:Actins / Q000737:chemistry; D001905:Botulinum Toxins / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D004594:Electrophysiology; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism; D005799:Genes, Dominant; D006801:Humans; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018613:Microscopy, Confocal; D008954:Models, Biological; D018408:Patch-Clamp Techniques; D011233:Precipitin Tests; D011485:Protein Binding; D021381:Protein Transport; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry* / Q000378:metabolism; D015398:Signal Transduction; D050052:TRPC Cation Channels; D019284:Thapsigargin / Q000737:chemistry / Q000494:pharmacology; D013917:Thrombin / Q000737:chemistry; D013997:Time Factors; D014162:Transfection; D020741:rho GTP-Binding Proteins / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000737:chemistry / Q000378:metabolism*
D000199:Actins; D015220:Calcium Channels; C506926:ITPR1 protein, human; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D050052:TRPC Cation Channels; C096351:transient receptor potential cation channel, subfamily C, member 1; D019284:Thapsigargin; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D013917:Thrombin; D001905:Botulinum Toxins; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein; D002118:Calcium