Inhibition of cellular response to platelet-derived growth factor by low M(r) phosphotyrosine protein phosphatase overexpression.
The role of low M(r) phosphotyrosine protein phosphatase (PTPase) in the control of cell proliferation was studied. A synthetic gene coding for PTPase was transfected and expressed in NIH/3T3 fibroblasts. The effects of the enzyme were particularly evident when cells were stimulated by platelet-derived growth factor (PDGF). The mitogenic response to PDGF was decreased and the inhibition reached 90%. This effect was more pronounced with respect to fetal calf serum stimulation. Hormone-dependent autophosphorylation of the PDGF receptor was significantly reduced. These results demonstrate that low M(r) PTPase, a cytosolic enzyme, not only affects cellular response to PDGF but also reduces the membrane receptor autophosphorylation.
Berti
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A
Dipartimento di Scienze Biochimiche, Università di Firenze, Florence, Italy.
Rigacci
S
S
Raugei
G
G
Degl'Innocenti
D
D
Ramponi
G
G
D016475:3T3 Cells; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D051379:Mice; D010750:Phosphoproteins / Q000378:metabolism*; D019000:Phosphotyrosine; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D017027:Protein Tyrosine Phosphatases / Q000096:biosynthesis* / Q000235:genetics; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis; D014162:Transfection; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
D010750:Phosphoproteins; D010982:Platelet-Derived Growth Factor; D011994:Recombinant Proteins; D019000:Phosphotyrosine; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D017027:Protein Tyrosine Phosphatases