Receptor specificity of growth factor-stimulated synthesis of 3-phosphorylated inositol lipids in Swiss 3T3 cells.
We have investigated synthesis of 3-phosphorylated inositol lipids in growth factor-stimulated Swiss 3T3 cells. Those growth factors tested which act via tyrosine kinase-containing receptors (platelet-derived growth factor (PDGF), insulin growth factor I (IGF-I), epidermal growth factor (EGF), and basic fibroblast growth factor (bFGF)) caused the rapid synthesis of [32P]PtdIns(3,4)P2 and [32P]PtdIns(3,4,5)P3 (PtdIns is phosphatidylinositol) in [32P]P(i)-prelabeled cells and the appearance of an inositol lipid 3-OH kinase in antiphosphotyrosine immunoprecipates. In contrast, those growth factors tested which act via G-protein-coupled receptors (bombesin, vasopressin, prostaglandin E1) were unable to stimulate either of the above responses. Furthermore, while PDGF was able to increase the formation of PtdIns(3,4)P2 and PtdIns(3,4,5)P3 in streptolysin-permeabilized cells, guanosine 5'-3-(thio)triphosphate and guanyl-5'-yl imidodiphosphate were not. These results suggest that Swiss 3T3 cells possess the machinery for tyrosine kinase but not G-protein-mediated activation of PtdIns(4,5)P2 3-OH kinase; a situation which is the inverse to that recently described for human neutrophils. The tyrosine kinase-containing receptors differed markedly in their relative abilities to elevate the levels of [32P] PtdIns(3,4,5)P3 (ranked in the order PDGF greater than or equal to IGF-I greater than EGF greater than bFGF), [32P]Ptd-OH (PDGF greater than EGF greater than bFGF; undetectable for IGF-I), and [32P]PtdIns4P (EGF greater than bFGF greater than PDGF; undetectable for IGF-I) in [32P]P(i)-prelabeled cells. These differences are epitomized by IGF-I, which was the joint most powerful stimulus for [32P] PtdIns(3,4,5)P3 formation, but was unable to stimulate a measurable accumulation of [32P]Ptd-OH (and hence, by deduction, was unable to stimulate phospholipase C). These results indicate that there is a differential ability among the tyrosine kinase-containing receptors present in a single cell to recruit phospholipase C and PtdIns(4,5)P2 3-OH kinase into their signalling complexes and further emphasizes the notion that the rapid synthesis of PtdIns(3,4,5)P3 may be a signalling event.
Jackson
T R
TR
Department of Biochemistry, Institute of Animal Physiology and Genetics Research, Babraham, Cambridge, United Kingdom.
Stephens
L R
LR
Hawkins
P T
PT
D019870:1-Phosphatidylinositol 4-Kinase; D016475:3T3 Cells; D000527:Alprostadil / Q000494:pharmacology; D000818:Animals; D001839:Bombesin / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D006133:Growth Substances / Q000494:pharmacology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D006728:Hormones / Q000494:pharmacology*; D007295:Inositol Phosphates / Q000302:isolation & purification / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D007700:Kinetics; D051379:Mice; D010710:Phosphates / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases; D010761:Phosphorus Radioisotopes; D010770:Phosphotransferases / Q000378:metabolism*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014667:Vasopressins / Q000494:pharmacology
D006133:Growth Substances; D006728:Hormones; D007295:Inositol Phosphates; D007328:Insulin; D010710:Phosphates; D010761:Phosphorus Radioisotopes; D010982:Platelet-Derived Growth Factor; D011956:Receptors, Cell Surface; D016222:Fibroblast Growth Factor 2; D014667:Vasopressins; D006165:Guanylyl Imidodiphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I; D010770:Phosphotransferases; D019869:Phosphatidylinositol 3-Kinases; D019870:1-Phosphatidylinositol 4-Kinase; D000527:Alprostadil; D013755:Tetradecanoylphorbol Acetate; D001839:Bombesin