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Activation of Xenopus Chk1 by mutagenesis of threonine‐377
Author(s) -
Wang Sophie X,
Dunphy William G
Publication year - 2000
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(00)02370-x
Subject(s) - xenopus , phosphorylation , threonine , mutagenesis , biology , protein kinase domain , dna , protein kinase a , kinase , microbiology and biotechnology , chemistry , biochemistry , serine , mutation , mutant , gene
Xenopus Chk1 (Xchk1) is required for the checkpoint‐associated delay of the cell cycle in frog egg extracts containing unreplicated or UV‐damaged DNA. Phosphorylation of Xchk1 at multiple sites in the SQ/TQ domain (residues 314–366) in response to unreplicated or UV‐damaged DNA results in elevation of its kinase activity. We have found that mutagenesis of Thr‐377 in the conserved Thr–Arg–Phe (TRF) motif of Xchk1 also leads to a substantial increase in kinase activity. Thr‐377 does not appear to be a site of phosphorylation in Xchk1. These findings suggest that Thr‐377 may play a role in suppressing the activity of Xchk1.