The low M r phosphotyrosine protein phosphatase behaves differently when phosphorylated at Tyr131 or Tyr132 by Src kinase

FEBS Letters

Raugei, Giovanni¹  Stefani, Massimo¹  Bucciantini, Monica¹  Ramponi, Giampietro¹  Taddei, Letizia¹  Nordlund, Par²  Cirri, Paolo¹  Chiarugi, Paola¹ 

[1]Department of Biochemical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence, Italy

[2]Department of Biochemistry, University of Stockholm, Stockholm, Sweden

关键词: Phosphotyrosine protein phosphatase;    Low molecular weight PTP;    PTP phosphorylation;    PTP activation;    Docking protein;    Grb2;    Src kinase;    PTP;    phosphotyrosine protein phosphatase;    LMW-PTP;    low molecular weight phosphotyrosine protein phosphatase;    SH2;    Src homology 2;    Grb2;    growth factor receptor binding protein-2;    PDGF;    platelet-derived growth factor;    PDGF-R;    platelet-derived growth factor receptor;    EGF;    epidermal growth factor;    GST;    glutathione S-transferase;    STAT;    signal transducer and activator of transcription;    IPTG;    isopropylthiogalactoside;    EDTA;    ethylenediaminetetraacetic acid;    PNPP;    p-nitrophenylphosphate;    TFA;    trifluoroacetic acid;    TIS;    triisopropylsilane;    HATU;    [O-(7-azabenzotriazol-1-yl)1;    1;    3;    3-tetramethyluronium hexafluorophosphate];    PMFS;    phenylmethylsulphonylfluoride;    HPLC;    high pressure liquid chromatography;    SDS-PAGE;    sodium dodecylsulphate polyacrylamide gel electrophoresis;   

DOI  :  10.1016/S0014-5793(99)00828-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The low molecular weight phosphotyrosine protein phosphatase (LMW-PTP) is phosphorylated by Src and Src-related kinases both in vitro and in vivo; in Jurkat cells, and in NIH-3T3 cells, it becomes tyrosine-phosphorylated upon stimulation by PDGF. In this study we show that pp60^Src phosphorylates in vitro the enzyme at two tyrosine residues, Tyr¹³¹ and Tyr¹³², previously indicated as the main phosphorylation sites of the enzyme, whereas phosphorylation by the PDGF-R kinase is much less effective and not specific. The effects of LMW-PTP phosphorylation at each tyrosine residue were investigated by using Tyr¹³¹ and Tyr¹³² mutants. We found that the phosphorylation at either residue has differing effects on the enzyme behaviour: Tyr¹³¹ phosphorylation is followed by a strong (about 25-fold) increase of the enzyme specific activity, whereas phosphorylation at Tyr¹³² leads to Grb2 recruitment. These differing effects are discussed on the light of the enzyme structure.

【 授权许可】

Unknown