SHP-2 phosphatase regulates DNA damage-induced apoptosis and G2/M arrest in catalytically dependent and independent manners, respectively.
SHP-2, a tyrosine phosphatase implicated in diverse signaling pathways induced by growth factors and cytokines, is also involved in DNA damage-triggered signaling and cellular responses. We previously demonstrated that SHP-2 played an important role in DNA damage-induced apoptosis and G2/M cell cycle checkpoint. In the present studies, we have provided evidence that SHP-2 functions in DNA damage apoptosis and G2/M arrest in catalytically dependent and independent manners, respectively. Mutant embryonic fibroblasts with the Exon 3 deletion mutation in SHP-2 showed decreased apoptosis and diminished G2/M arrest in response to cisplatin treatment. Wild type (WT), but not catalytically inactive mutant SHP-2 (SHP-2 C459S), rescued the apoptotic response of the mutant cells. Interestingly, both WT and SHP-2 C459S efficiently restored the G2/M arrest response. Furthermore, inhibition of the catalytic activity of endogenous SHP-2 in WT cells by overexpression of SHP-2 C459S greatly decreased cell death but not G2/M arrest induced by cisplatin. Biochemical analyses revealed that activation of c-Abl kinase was decreased in SHP-2 C459S-overexpressing cells. However, DNA damage-induced translocation of Cdc25C from the nucleus to the cytoplasm was fully restored in both WT and SHP-2 C459S "rescued" cells. Additionally, we demonstrated that the role of SHP-2 in DNA damage-induced cellular responses was independent of the tumor suppressor p53. Embryonic stem cells with the SHP-2 deletion mutation showed markedly decreased sensitivity to cisplatin-induced apoptosis, attributed to impaired induction of p73 but not p53. In agreement with these results, DNA damage-induced apoptosis and G2/M arrest were also decreased in SHP-2/p53 double mutant embryonic fibroblasts. Collectively, these studies have further defined the mechanisms by which SHP-2 phosphatase regulates DNA damage responses.
Yuan
Liangping
L
Department of Medicine, Division of Hematology/Oncology, Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio 44106, USA.
Yu
Wen-Mei
WM
Xu
Min
M
Qu
Cheng-Kui
CK
D000818:Animals; D017209:Apoptosis; D002384:Catalysis; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D002469:Cell Separation; D002945:Cisplatin / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism; D004249:DNA Damage; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D005091:Exons; D005347:Fibroblasts / Q000378:metabolism; D005434:Flow Cytometry; D016195:G2 Phase; D017353:Gene Deletion; D015971:Gene Expression Regulation, Enzymologic; D018014:Gene Transfer Techniques; D016147:Genes, Tumor Suppressor; D015151:Immunoblotting; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D051379:Mice; D008938:Mitosis; D009687:Nuclear Proteins / Q000378:metabolism; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D011839:Radiation, Ionizing; D012190:Retroviridae / Q000235:genetics; D015398:Signal Transduction; D013234:Stem Cells / Q000378:metabolism; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025521:Tumor Suppressor Proteins; D020687:cdc25 Phosphatases / Q000378:metabolism
D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; C000606368:Trp73 protein, mouse; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C517010:Cdc25c protein, mouse; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse; D020687:cdc25 Phosphatases; D002945:Cisplatin