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In vivo phosphorylation of poly(ADP‐ribose) polymerase is independent of its activation
Author(s) -
Ariumi Yasuo,
Ueda Kunihiro,
Masutani Mitsuko,
Copeland Terry D,
Noda Makoto,
Hatanaka Masakazu,
Shimotohno Kunitada
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)01144-2
Subject(s) - poly adp ribose polymerase , microbiology and biotechnology , phosphorylation , jurkat cells , polymerase , chemistry , kinase , biology , biochemistry , enzyme , t cell , genetics , immune system
Poly(ADP‐ribose) polymerase (PARP) is a nuclear enzyme, which is activated by DNA strand breaks. Although PARP is known to be cleaved by the cysteine protease, caspase‐3/CPP32, during apoptosis, signal cascade which regulates the PARP activity has not been fully understood. In this study, we investigated post‐translational modification of PARP. We found that PARP was phosphorylated by a serine kinase in vivo. PARP was activated temporarily and extensive auto‐modification occurred on PARP, possibly by the fragmented DNA during apoptosis induced by etoposide in Jurkat cells. However, the phosphorylation level was not changed for up to 6 h, after PARP cleavage began in apoptosis by the treatment with etoposide. Furthermore, we showed the presence of a PARP‐associated kinase in nuclear extracts of the HTLV‐I infected T‐cell lines but not in uninfected T‐cell lines, whereas this kinase did not inhibit the PARP activity even in the presence of ATP. Taken together, in vivo phosphorylation of PARP might be independent of the activation or cleavage of PARP.