Tyrosine mutations within the alpha platelet-derived growth factor receptor kinase insert domain abrogate receptor-associated phosphatidylinositol-3 kinase activity without affecting mitogenic or chemotactic signal transduction.
A phosphatidylinositol-3 (PI-3) kinase activity of unknown biological function associates with tyrosine kinase-containing proteins, including a number of growth factor receptors after ligand stimulation. In the beta platelet-derived growth factor (beta PDGF) receptor, phosphorylation of a specific tyrosine residue within the kinase insert domain was required for its interaction with this enzyme. We show that substitutions of phenylalanine for tyrosine residue 731 or 742 within the kinase insert domain of the alpha PDGF receptor do not impair PDGF-induced tyrosine phosphorylation of the receptor or of an in vivo substrate, phospholipase C-gamma. Moreover, phosphatidylinositol turnover in response to ligand stimulation is unaffected. However, both lesions markedly impair receptor association with PI-3 kinase. Antiphosphotyrosine antibody-recoverable PI-3 kinase was also dramatically reduced in PDGF-stimulated cells expressing either mutant receptor. Since neither mutation abolished PDGF-induced mitogenesis or chemotaxis, we conclude that alpha PDGF receptor-associated PI-3 kinase activity is not required for either of these major PDGF signalling functions.
Yu
J C
JC
Laboratory of Cellular and Molecular Biology, National Cancer Institute (37-1E24), Bethesda, Maryland 20892.
Heidaran
M A
MA
Pierce
J H
JH
Gutkind
J S
JS
Lombardi
D
D
Ruggiero
M
M
Aaronson
S A
SA
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002633:Chemotaxis / Q000187:drug effects; D007377:Interleukin-3 / Q000494:pharmacology; D007700:Kinetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D015345:Oligonucleotide Probes; D019869:Phosphatidylinositol 3-Kinases; D010766:Phosphorylation; D010770:Phosphotransferases / Q000378:metabolism*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017479:Receptors, Platelet-Derived Growth Factor; D011994:Recombinant Proteins / Q000494:pharmacology; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection; D014443:Tyrosine
D007377:Interleukin-3; D015345:Oligonucleotide Probes; D010982:Platelet-Derived Growth Factor; D011994:Recombinant Proteins; D014443:Tyrosine; D010770:Phosphotransferases; D011494:Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D017479:Receptors, Platelet-Derived Growth Factor