Functional expression of Ca2(+)-mobilizing alpha-thrombin receptors in mRNA-injected Xenopus oocytes.
alpha-Thrombin (TH) initiates a program of intracellular events that lead to DNA replication in quiescent CCL39 Chinese hamster lung fibroblasts via membrane receptors that have yet to be characterized at a molecular level. Functional TH receptors were expressed in Xenopus laevis oocytes following injection of poly(A)+ RNA from TH-responsive CCL39 cells; their presence was demonstrated by TH-stimulated 45Ca2+ efflux or Ca2(+)-dependent Cl- channel activation. In voltage clamp experiments on microinjected oocytes a Ca2(+)-activated Cl- current was detected in response to TH (0.2-10 U/ml). The TH response was blocked by a specific TH inhibitor, and potentiated by addition of FGF or intracellular injection of GTP-gamma-S.
Van Obberghen-Schilling
E
E
Centre de Biochimie, C.N.R.S., Nice, France.
Chambard
J C
JC
Lory
P
P
Nargeot
J
J
Pouysségur
J
J
D000818:Animals; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism*; D018118:Chloride Channels; D002712:Chlorides / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D005346:Fibroblast Growth Factors / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000494:pharmacology; D005786:Gene Expression Regulation; D008565:Membrane Proteins / Q000378:metabolism*; D009865:Oocytes; D012333:RNA, Messenger / Q000096:biosynthesis*; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D018179:Receptors, Thrombin; D013917:Thrombin / Q000494:pharmacology; D014982:Xenopus laevis
D018118:Chloride Channels; D002712:Chlorides; D008565:Membrane Proteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D018179:Receptors, Thrombin; D005346:Fibroblast Growth Factors; D013917:Thrombin; D019204:GTP-Binding Proteins; D002118:Calcium