title: RhoA interaction with inositol 1,4,5-trisphosphate receptor and transient receptor potential channel-1 regulates Ca2+ entry. Role in signaling increased endothelial permeability.
abstract: 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.
authors.affiliation: Department of Pharmacology, College of Medicine, The University of Illinois, Chicago, Illinois 60612, USA. dmehta@uic.edu
authors.forename: Dolly
authors.initials: D
authors.lastname: Mehta
authors.forename: Gias U
authors.initials: GU
authors.lastname: Ahmmed
authors.forename: Biman C
authors.initials: BC
authors.lastname: Paria
authors.forename: Michael
authors.initials: M
authors.lastname: Holinstat
authors.forename: Tatyana
authors.initials: T
authors.lastname: Voyno-Yasenetskaya
authors.forename: Chinnaswamy
authors.initials: C
authors.lastname: Tiruppathi
authors.forename: Richard D
authors.initials: RD
authors.lastname: Minshall
authors.forename: Asrar B
authors.initials: AB
authors.lastname: Malik
mesh_terms: 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*
chemical_list: 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