文章基本信息

标题：Role of Polo-like kinase 1 in the regulation of the action of p31comet in the disassembly of mitotic checkpoint complexes
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作者：Sharon Kaisari ; Sharon Kaisari ; Pnina Shomer 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2019
卷号：116
期号：24
页码：11725-11730
DOI：10.1073/pnas.1902970116
出版社：The National Academy of Sciences of the United States of America
摘要：The Mad2-binding protein p31^comet has important roles in the inactivation of the mitotic checkpoint system, which delays anaphase until chromosomes attach correctly to the mitotic spindle. The activation of the checkpoint promotes the assembly of a Mitotic Checkpoint Complex (MCC), which inhibits the action of the ubiquitin ligase APC/C (Anaphase-Promoting Complex/Cyclosome) to degrade inhibitors of anaphase initiation. The inactivation of the mitotic checkpoint requires the disassembly of MCC. p31^comet promotes the disassembly of mitotic checkpoint complexes by liberating their Mad2 component in a joint action with the ATPase TRIP13. Here, we investigated the regulation of p31^comet action. The release of Mad2 from checkpoint complexes in extracts from nocodazole-arrested HeLa cells was inhibited by Polo-like kinase 1 (Plk1), as suggested by the effects of selective inhibitors of Plk1. Purified Plk1 bound to p31^comet and phosphorylated it, resulting in the suppression of its activity (with TRIP13) to disassemble checkpoint complexes. Plk1 phosphorylated p31^comet on S102, as suggested by the prevention of the phosphorylation of this residue in checkpoint extracts by the selective Plk1 inhibitor BI-2536 and by the phosphorylation of S102 with purified Plk1. An S102A mutant of p31^comet had a greatly decreased sensitivity to inhibition by Plk1 of its action to disassemble mitotic checkpoint complexes. We propose that the phosphorylation of p31^comet by Plk1 prevents a futile cycle of MCC assembly and disassembly during the active mitotic checkpoint.
关键词：cell cycle ; protein degradation ; mitosis