Protein tyrosine phosphorylation activates rat splenic type II phosphatidylinositol 4‐kinase in vitro

FEBS Letters

Fernandis, Aaron Z¹  Subrahmanyam, Gosukonda¹ 

[1] Biotechnology Centre, Indian Institute of Technology, Bombay Powai, Mumbai, PIN 400076, India

关键词: T cell activation;    Signal transduction;    Protein phosphatase;    PtdIns(4;    5)P 2;    d-myo-phosphatidylinositol 4;    5-bisphosphate;    PtdIns4P;    d-myo-phosphatidylinositol 4-phosphate;    PtdIns;    d-myo-phosphatidylinositol;    PtdIns 4-kinase;    phosphatidylinositol 4-kinase;    EGF;    epidermal growth factor;    PMSF;    phenylmethylsulfonyl fluoride;    Pefabloc SC;    4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride;    Con A;    concanavalin A;    pNPP;    para-nitrophenyl phosphate;    PTK;    protein tyrosine kinase;    PTPase;    protein phosphotyrosine phosphatase;    PP2A;    protein phosphatase 2A;    SDS-PAGE;    sodium dodecyl sulfate-polyacrylamide gel electrophoresis;   

DOI  :  10.1016/S0014-5793(98)01604-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Regulation of phosphatidylinositol 4-kinase (PtdIns 4-kinase) by protein tyrosine phosphorylation has been indirect and the effects of phosphorylation are debatable. Rat splenic type II PtdIns 4-kinase was phosphorylated in vitro with protein tyrosine kinases from Con A stimulated splenic lymphocytes. Stoichiometric analysis showed one mole of phosphate was incorporated per mole of PtdIns 4-kinase. Tyrosine phosphorylation increased the enzyme activity by 3-fold. Kinetic analysis showed a reduction in K _m for PtdIns and an increase in V _max. Dephosphorylation with protein phosphotyrosine phosphatase abolished the activation of PtdIns 4-kinase while protein phosphatase 2A had no effect. Protein tyrosine phosphorylation and activation of PtdIns 4-kinase appear to be tissue specific.

【 授权许可】

Unknown