Control of Mitotic Entry by Regulators of Cdc2

Cdc2 调节剂对有丝分裂进入的控制

• 批准号: 7314425
• 负责人: Sally A Kornbluth
• 金额: $ 27.3万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7314425
• 关键词: Affinity; Apoptotic; Binding; Cell Cycle Checkpoint; Characteristics; Complex; Cyclin B; DNA Sequence Rearrangement; DNA biosynthesis; Dissociation; Excision; Goals; Intermediate Filament Proteins; Mediating; Mitosis; Mitotic; Operative Surgical Procedures; Pathway interactions; Phosphorylation; Phosphotransferases; Proteins; Regulation; Role; Upper arm; cdc25 Phosphatase; inhibitor/antagonist; novel; prevent

DESCRIPTION (provided by applicant): Entry into mitosis catalyzed by the Cdc2/Cyclin B kinase, which phosphorylates multiple proteins to induce the dramatic cellular rearrangements characteristic of mitosis. When DNA replication is inhibited, a cell cycle checkpoint pathway prevents mitosis through inhibitory phosphorylation of Cdc2 at Y15 and T14. This inhibition involves sustained activity of the Cdc2 Y15-directed kinase, Wee1, as well as suppression of the Cdc2 Y15 phosphatase, Cdc25. We have discovered that a novel G2/M regulator, Hsl7, promotes intranuclear Wee1 degradation, and that the DNA replication checkpoint disrupts Hsl7-Wee1 interactions. In parallel, Cdc25 is inhibited through binding to 14-3-3 protein. Removal of 14-3-3 from Cdc25 is required for its mitotic activation, and we have found that dissociation of the 14-3-3-Cdc25 complex requires phosphorylation of both Cdc25 T138 (which reduces the affinity of 14-3-3 for Cdc25) and intermediate filament proteins (which then bind 14-3-3, thereby serving as an abundant 14-3-3 "sink"). Additionally, we have discovered that a previously described apoptotic inhibitor, Aven, can also regulate mitotic entry and may be important for DNA-responsive checkpoint operation. The objective of this proposal to elucidate both the Wee1 and Cdc25-modulatory arms of DNA-responsive checkpoint pathways with the long term goal of fully understanding the control of M phase entry. Towards this end, we propose to I) Delineate the role of Hsl7 in checkpoint-mediated Wee1 regulation II) Elucidate the mechanism(s) which regulate 14-3-3 release from Cdc25 and III) Determine how Aven regulates mitotic entry.

描述（由申请人提供）：Cdc2/Cyclin B激酶催化有丝分裂的菌丝分裂，该酶磷酸化多种蛋白质以诱导有丝分裂的戏剧性细胞重排特征。当抑制DNA复制时，细胞周期检查点途径通过Y15和T14的CDC2抑制性磷酸化来阻止有丝分裂。这种抑制作用涉及Cdc2 Y15定向激酶WEE1的持续活性，以及​​抑制Cdc2 Y15磷酸酶Cdc25。我们发现一种新型的G2/M调节剂HSL7促进了核内WEE1降解，并且DNA复制检查点破坏了HSL7-WEE1的相互作用。同时，通过与14-3-3蛋白结合来抑制CDC25。 Removal of 14-3-3 from Cdc25 is required for its mitotic activation, and we have found that dissociation of the 14-3-3-Cdc25 complex requires phosphorylation of both Cdc25 T138 (which reduces the affinity of 14-3-3 for Cdc25) and intermediate filament proteins (which then bind 14-3-3, thereby serving as an abundant 14-3-3 "sink").此外，我们发现先前描述的凋亡抑制剂Aven也可以调节有丝分裂的进入，对于DNA反应性检查点的操作可能很重要。该提议的目的是阐明DNA响应性检查点途径的WEE1和CDC25调节臂，其长期目标是充分理解M相进入的控制。为此，我们建议i）描述HSL7在检查点介导的WEE1调节中的作用II）阐明了调节CDC25和III释放14-3-3释放的机制，确定AVEN如何调节有丝分裂进入。