Endothelin receptor is coupled to phospholipase C via a pertussis toxin-insensitive guanine nucleotide-binding regulatory protein in vascular smooth muscle cells.
The mechanisms of endothelin-1 (ET) actions were investigated in cultured rat aortic vascular smooth muscle A-10 cells. The A-10 cells have a single class of high affinity binding sites for ET with an apparent Mr of 65,000-75,000 on SDS-PAGE. Stimulation of cells with ET induces mobilization of Ca2+ from both intra- and extracellular pools to produce a biphasic increase in cytoplasmic free Ca2+ concentration. ET increases cellular levels of inositol trisphosphate and 1,2-diacylglycerol, indicating activation of phospholipase C by ET. ET stimulates production of inositol phosphates in membranes prepared from A-10 cells in the presence of guanosine 5'-O-(thiotriphosphate) (GTP gamma S), but not in its absence. Further, specific binding of 125I-labeled ET to A-10 cell membranes is shown to be inhibited by GTP gamma S in a dose-dependent manner. Treatment of A-10 cells with pertussis toxin induces ADP-ribosylation of a 41,000-D membrane protein but fails to block the ET-induced increases in inositol phosphate production and Ca2+ mobilization. These results indicate that the receptor for ET is coupled to phospholipase C via a guanine nucleotide-binding regulatory protein which is distinct from the pertussis toxin substrate in A-10 cells.
Takuwa
Y
Y
Department of Internal Medicine, University of Tsukuba, Ibaraki, Japan.
Kasuya
Y
Y
Takuwa
N
N
Kudo
M
M
Yanagisawa
M
M
Goto
K
K
Masaki
T
T
Yamashita
K
K
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D004075:Diglycerides / Q000096:biosynthesis; D016232:Endothelins; D004730:Endothelium, Vascular / Q000502:physiology*; D019204:GTP-Binding Proteins / Q000502:physiology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D007295:Inositol Phosphates / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D010455:Peptides / Q000378:metabolism / Q000494:pharmacology*; D037342:Pertussis Toxin; D051381:Rats; D011956:Receptors, Cell Surface / Q000032:analysis* / Q000187:drug effects; D017466:Receptors, Endothelin; D013873:Thionucleotides / Q000494:pharmacology; D010738:Type C Phospholipases / Q000032:analysis*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
C011439:1,2-diacylglycerol; D004075:Diglycerides; D016232:Endothelins; D007295:Inositol Phosphates; D010455:Peptides; D011956:Receptors, Cell Surface; D017466:Receptors, Endothelin; D013873:Thionucleotides; D010566:Virulence Factors, Bordetella; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D037342:Pertussis Toxin; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins; D002118:Calcium