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）：由 Cdc2/细胞周期蛋白 B 激酶催化进入有丝分裂，其磷酸化多种蛋白质以诱导有丝分裂特征的剧烈细胞重排。当 DNA 复制受到抑制时，细胞周期检查点途径通过在 Y15 和 T14 处 Cdc2 的抑制性磷酸化来阻止有丝分裂。这种抑制涉及 Cdc2 Y15 定向激酶 Wee1 的持续活性，以及​​ Cdc2 Y15 磷酸酶 Cdc25 的抑制。我们发现一种新的 G2/M 调节因子 Hsl7 可促进核内 Wee1 降解，并且 DNA 复制检查点会破坏 Hsl7-Wee1 相互作用。同时，Cdc25 通过与 14-3-3 蛋白结合而受到抑制。有丝分裂激活需要从 Cdc25 中去除 14-3-3，我们发现 14-3-3-Cdc25 复合物的解离需要 Cdc25 T138 的磷酸化（这会降低 14-3-3 对Cdc25）和中间丝蛋白（然后结合 14-3-3，从而充当丰富的 14-3-3“库”）。此外，我们发现先前描述的细胞凋亡抑制剂 Aven 也可以调节有丝分裂进入，并且可能对 DNA 响应检查点操作很重要。该提案的目的是阐明 DNA 响应检查点通路的 Wee1 和 Cdc25 调节臂，长期目标是充分了解 M 期进入的控制。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) 阐明调节 Cdc25 14-3-3 释放的机制和 III) 确定 Aven 如何调节有丝分裂进入。