Novel functions of the phosphatase SHP2 in the DNA replication and damage checkpoints

• Published in: PloS one 2012-11, Vol.7 (11), p.e49943
• Main Authors: Tsang, Yiu Huen, Han, Xianxian, Man, Wing Yu, Lee, Nelson, Poon, Randy Y C
• Format: Article
• Language: English
• Subjects: Activation; Apoptosis; Biology; Cancer; Cell activation; Cell cycle; Cell Cycle Checkpoints - drug effects; Cell Cycle Checkpoints - genetics; Cell death; Cell survival; Cell Survival - drug effects; Cell Survival - genetics; Checkpoint Kinase 1; CHK1 protein; Cisplatin; Cisplatin - pharmacology; Cyclin E; Cyclin E - metabolism; Deoxyribonucleic acid; Depletion; DNA; DNA biosynthesis; DNA damage; DNA Damage - drug effects; DNA repair; DNA Replication; Enzyme Activation; Enzyme Inhibitors - pharmacology; G1 phase; Gene Expression Regulation - drug effects; Genetic research; Genomes; Growth factors; HeLa Cells; Humans; Hydroxyurea; Hydroxyurea - pharmacology; Ionizing radiation; Kinases; Leukemia; Life sciences; Medical research; Mutation; Nucleic Acid Synthesis Inhibitors - pharmacology; Phosphatase; Phosphatases; Phosphorylation; Protein Kinases - metabolism; Protein Tyrosine Phosphatase, Non-Receptor Type 11 - genetics; Protein Tyrosine Phosphatase, Non-Receptor Type 11 - metabolism; Proteins; Radiation; Radiation damage; Replication; Ribonucleic acid; RNA; RNA Interference; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism; RNA-mediated interference; Rodents; S Phase; Screens; Signal transduction; Stress; Stresses
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0049943

Replication stress- and DNA damage-induced cell cycle checkpoints are critical for maintaining genome stability. To identify protein phosphatases involved in the activation and maintenance of the checkpoints, we have carried out RNA interference-based screens with a human phosphatome shRNA library. Several phosphatases, including SHP2 (also called PTPN11) were found to be required for cell survival upon hydroxyurea-induced replicative stress in HeLa cells. More detailed studies revealed that SHP2 was also important for the maintenance of the checkpoint after DNA damage induced by cisplatin or ionizing radiation in HeLa cells. Furthermore, SHP2 was activated after replicative stress and DNA damage. Although depletion of SHP2 resulted in a delay in cyclin E accumulation and an extension of G(1) phase, these cell cycle impairments were not responsible for the increase in apoptosis after DNA damage. Depletion of SHP2 impaired CHK1 activation, checkpoint-mediated cell cycle arrest, and DNA repair. These effects could be rescued with a shRNA-resistant SHP2. These results underscore the importance of protein phosphatases in checkpoint control and revealed a novel link between SHP2 and cell cycle checkpoints.