PDGF receptor as a specific in vivo target for low M r phosphotyrosine protein phosphatase

FEBS Letters

Ramponi, Giampietro¹  Dolfi, Fabrizio¹  Raugei, Giocanni¹  Camici, Guido¹  Cirri, Paolo¹  Berti, Andrea¹  Chiarugi, Paola¹ 

[1] Dipartimento di Scienze Biochimiche, Università di Firenze, Viale Morgagni 50, 50100 Firenze, Italy

关键词: Phosphotyrosine tyrosine phosphatase;    PDGF-R;    Negative dominant;    LMW-PTP;    low M r phosphotyrosine protein phosphatase;    PTPase;    protein tyrosine phosphatase;    PTK;    protein tyrosine kinase;    PDGF;    platelet derived growth factor;    EGF;    epidermal growth factor;    PDGF-R;    platelet derived growth factor receptor;    DMEM;    Dulbecco's modified Eagle's medium;    FCS;    fetal calf serum;   

DOI  :  10.1016/0014-5793(95)00947-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Low M _r phosphotyrosine protein phosphatase (LMWPTP) is a 18 kDa cytosolic enzyme widely distributed in eukaryotic cells. LMW-PTP catalyses the hydrolysis of phosphotyrosine residues and overexpression of the enzyme in normal and transformed cells inhibits cell proliferation. Site directed mutagenesis, together with crystallographic studies, have contributed to clarify the catalytic mechanism, which involves the active site signature sequence C₁₂XXXXXR₁₈, a main feature of all PTPase family members. In order to identify the LMW-PTP substratels we have expressed in NIH-3T3 cells a catalytically inert Cys¹² to Ser phosphatase mutant which has preserved its capacity for substrate binding. Overexpression of the mutant phosphatase leads to enhanced cell proliferation and serum induced mitogenesis, indicating that the mutation results in the production of a dominant negative protein. Analysis of mutant LMW-PTP expressing cells has enabled us to demonstrate an association between LMW-PTP and platelet derived growth factor receptor that appears to be highly specific. Our data suggest a catalytic action of LMW-PTP on the phosphorylated platelet derived growth factor receptor.

【 授权许可】

Unknown