Cleavage and phosphorylation of XRCC4 protein induced by X-irradiation

• Published in: FEBS letters 2000-07, Vol.478 (1), p.67-71
• Main Authors: Matsumoto, Yoshihisa, Suzuki, Norio, Namba, Naoki, Umeda, Noriko, Ma, Xue-Jun, Morita, Akinori, Tomita, Masanori, Enomoto, Atsushi, Serizawa, Shinobu, Hirano, Kazuya, Sakai, Kazuo, Yasuda, Hideyo, Hosoi, Yoshio
• Format: Article
• Language: English
• Subjects: Androstadienes - pharmacology; Apoptosis; Ataxia Telangiectasia Mutated Proteins; Ataxia-telangiectasia mutated; Blotting, Western; Caspase; Caspase 3; Caspase 7; Caspase Inhibitors; Caspases - metabolism; Cell Cycle Proteins; DNA double-strand break repair; DNA-Activated Protein Kinase; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - metabolism; DNA-Binding Proteins - radiation effects; DNA-dependent protein kinase; Hot Temperature; Humans; Molecular Weight; Nuclear Proteins; Peptide Fragments - chemistry; Peptide Fragments - metabolism; Peptide Fragments - radiation effects; Phosphatidylinositol 3-Kinases - antagonists & inhibitors; Phosphatidylinositol 3-Kinases - metabolism; Phosphorylation - radiation effects; Protein-Serine-Threonine Kinases - antagonists & inhibitors; Protein-Serine-Threonine Kinases - deficiency; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism; Recombinant Proteins - antagonists & inhibitors; Recombinant Proteins - metabolism; Tumor Cells, Cultured; Tumor Suppressor Proteins; U937 Cells; Wortmannin; XRCC4
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(00)01800-7

We report the p35 and p60 forms of XRCC4 protein, appearing in human leukemia MOLT-4 or U937 cells following X-irradiation or hyperthermia. p35 appeared in conjunction with the cleavage of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and the fragmentation of internucleosomal DNA, and was suppressed by Ac-DEVD-CHO. p35 was also produced in vitro by treating MOLT-4 cell lysate with recombinant caspases, suggesting that p35 was a caspase-cleaved fragment of XRCC4 in apoptotic cell death. p60 was sensitive to treatment with phosphatase or wortmannin and was undetectable in M059J cells deficient in DNA-PKcs. However, p60 was found in ataxia-telangiectasia cells after irradiation. These results indicated p60 as a phosphorylated form of XRCC4, requiring DNA-PKcs but not ataxia-telangiectasia mutated (ATM).