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Src kinase tyrosine phosphorylates PTP1C, a protein tyrosine phosphatase containing Src homology-2 domains that

T Matozaki1, T Uchida, Y Fujioka

  • 1Second Department of Internal Medicine, Kobe University School of Medicine, Japan.

Biochemical and Biophysical Research Communications
|October 28, 1994
PubMed

Insights

Protein-tyrosine phosphatase 1C (PTP1C) is directly phosphorylated by v-Src kinase. Overexpression of PTP1C inhibits cell proliferation and anchorage-independent growth in v-Src-transformed cells.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Protein-tyrosine phosphatase 1C (PTP1C) is a non-transmembrane phosphatase with two Src homology-2 (SH2) domains.
  • v-Src kinase is an oncogenic tyrosine kinase implicated in cell transformation and proliferation.

Purpose of the Study:

  • To investigate the interaction between PTP1C and v-Src kinase.
  • To determine the role of PTP1C in v-Src-mediated cell transformation.

Main Methods:

  • Tyrosine phosphorylation analysis of PTP1C in v-Src-transformed rat fibroblast cells (SR-3Y1).
  • In vitro kinase assays using v-Src kinase and PTP1C.
  • Assessment of cell growth rate and anchorage-independent colony formation upon PTP1C expression.

Main Results:

  • PTP1C undergoes tyrosine phosphorylation in SR-3Y1 cells, independent of its SH2 domains.
  • v-Src kinase directly catalyzes the phosphorylation of PTP1C.
  • Expression of PTP1C reduces the growth rate and suppresses anchorage-independent colony formation of SR-3Y1 cells.

Conclusions:

  • PTP1C is a direct substrate of v-Src kinase.
  • PTP1C may act as a negative regulator of cell proliferation in the context of v-Src transformation.

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