title: Activation of polyphosphoinositide phospholipase C by guanosine 5'-O-(3-thio)triphosphate and fluoroaluminate in membranes prepared from a human T cell leukemia line, JURKAT.
abstract: Polyphosphoinositide hydrolysis was studied in membranes prepared from a human T cell leukemia line, JURKAT, prelabeled with myo-[2-3H]inositol. The formation of inositol bis- and trisphosphates was stimulated in a buffer with 110 nM free Ca2+ with a nonhydrolyzable GTP analogue, GTP gamma S, and NaF plus AlCl3 in a time- and concentration-dependent manner. GTP gamma S and NaF-AlCl3 had no significant effect on the inositol monophosphate level. AlCl3 enhanced the NaF-stimulated release of inositol polyphosphates. Optimum concentrations of NaF and AlCl3 produced 1.5-fold more inositol polyphosphates than that produced by optimum concentration of GTP gamma S. OKT3 monoclonal antibody, an antibody against the T-cell receptor complex, did not stimulate the inositol polyphosphate formation by JURKAT membranes even in the presence of GTP, although the antibody at the concentrations used markedly stimulated the hydrolysis of polyphosphoinositides in intact JURKAT cells.
mesh_terms: D000535:Aluminum / Q000494:pharmacology*; D000077410:Aluminum Chloride; D017607:Aluminum Compounds; D000911:Antibodies, Monoclonal / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology / Q000502:physiology; D017252:CD3 Complex; D002460:Cell Line; D002712:Chlorides / Q000494:pharmacology*; D006800:Deltaretrovirus Infections / Q000201:enzymology* / Q000473:pathology; D004789:Enzyme Activation / Q000187:drug effects; D019204:GTP-Binding Proteins / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D006868:Hydrolysis; D007295:Inositol Phosphates / Q000096:biosynthesis; D008565:Membrane Proteins / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000378:metabolism*; D012969:Sodium Fluoride / Q000494:pharmacology*; D013873:Thionucleotides / Q000494:pharmacology*; D010738:Type C Phospholipases / Q000378:metabolism*
chemical_list: D017607:Aluminum Compounds; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D017252:CD3 Complex; D002712:Chlorides; D007295:Inositol Phosphates; D008565:Membrane Proteins; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; D013873:Thionucleotides; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000077410:Aluminum Chloride; D006160:Guanosine Triphosphate; D012969:Sodium Fluoride; D000535:Aluminum; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins