DNA damage-induced G2/M checkpoint in SV40 large T antigen-immortalized embryonic fibroblast cells requires SHP-2 tyrosine phosphatase.
DNA damage induced by radiation or DNA-damaging agents leads to apoptosis and cell cycle arrest. However, DNA damage-triggered signal transduction involved in these cellular responses is not well understood. We previously demonstrated an important role for SHP-2, a ubiquitously expressed SH2 domain-containing tyrosine phosphatase, in the DNA damage-induced apoptotic response. ... Here we report a potential role for SHP-2 in a DNA damage-activated cell cycle checkpoint. Cell cycle analysis and the mitotic index assay showed that following DNA damage induced by cisplatin or gamma-irradiation, the G2 (but not S) arrest response was diminished in SV40 large T antigen-immortalized embryonic fibroblast cells lacking functional SHP-2. Notably, reintroduction of wild-type SHP-2 into the mutant cells fully restored the DNA damage-induced G2 arrest response, suggesting a direct role of SHP-2 in the G2/M checkpoint. Further biochemical analysis revealed that SHP-2 constitutively associated with 14-3-3beta, and that Cdc25C cytoplasmic translocation induced by DNA damage was essentially blocked in SHP-2 mutant cells. Additionally, we showed that following DNA damage, activation of p38 kinase was significantly elevated, while Erk kinase activation was decreased in mutant cells, and treatment of SHP-2 mutant cells with SB203580, a selective inhibitor for p38 kinase, partially restored the DNA damage-induced G2 arrest response. These results together provide the first evidence that SHP-2 tyrosine phosphatase enhances the DNA damage G2/M checkpoint in SV40 large T antigen immortalized murine embryonic fibroblast cells.
Mesh Terms:
Animals, Antigens, Polyomavirus Transforming, Caffeine, Cell Cycle, Cell Cycle Proteins, Cells, Cultured, Cisplatin, Cytoplasm, DNA, DNA Damage, Enzyme Inhibitors, Fibroblasts, G2 Phase, Gamma Rays, Immunoblotting, Intracellular Signaling Peptides and Proteins, Mice, Mitosis, Nocodazole, Precipitin Tests, Protein Transport, Protein Tyrosine Phosphatase, Non-Receptor Type 11, Protein Tyrosine Phosphatases, SH2 Domain-Containing Protein Tyrosine Phosphatases, Time Factors, cdc25 Phosphatases, src Homology Domains
Animals, Antigens, Polyomavirus Transforming, Caffeine, Cell Cycle, Cell Cycle Proteins, Cells, Cultured, Cisplatin, Cytoplasm, DNA, DNA Damage, Enzyme Inhibitors, Fibroblasts, G2 Phase, Gamma Rays, Immunoblotting, Intracellular Signaling Peptides and Proteins, Mice, Mitosis, Nocodazole, Precipitin Tests, Protein Transport, Protein Tyrosine Phosphatase, Non-Receptor Type 11, Protein Tyrosine Phosphatases, SH2 Domain-Containing Protein Tyrosine Phosphatases, Time Factors, cdc25 Phosphatases, src Homology Domains
J. Biol. Chem.
Date: Oct. 31, 2003
PubMed ID: 12937170
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