Anaphase Promoting Complex-mediated Proteolysis

后期促进复合物介导的蛋白水解

• 批准号: 7017968
• 负责人: MARK J SOLOMON
• 金额: $ 35.15万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7017968
• 关键词: DNA replication; cell cycle; cell growth regulation; enzyme activity; enzyme substrate complex; fungal proteins; gene expression; genetic library; genetic screening; microarray technology; mitotic spindle apparatus; proteolysis; ubiquitin; western blottings; yeasts

DESCRIPTION (provided by applicant): A key event in the progression through and exit from mitosis is the ubiquitin-dependent degradation of cyclins and other key proteins by the Anaphase Promoting Complex (APC; also called the cyclosome). APC substrates contain degradation motifs such as the Destruction Box and the KEN Box that are required for their ubiquitination and for their binding to the APC activators, Cdc20 and Cdh1. Both motifs are required for efficient degradation, but either one alone suffices for binding to Cdh1p. We have proposed a pathway for the assembly of the APC-Cdh1p-substrate complex in which APC-free Cdh1p first binds a substrate. Engagement of the substrate Destruction Box by Cdh1p stimulates the binding of Cdh1p to the APC, presumably via a conformation change in Cdh1p. The current studies are aimed at furthering our understanding of APC-mediated proteolysis in budding yeast. In particular, we wish to identify novel APC substrates, to understand how APC-Cdh1p/Cdc20p-substrate complexes are assembled and disassembled, and to understand how the spindle assembly checkpoint makes use of a KEN box to turn off APC-mediated proteolysis when chromosomes are not properly attached to the mitotic spindle. To achieve these goals, I propose the following Specific Aims: 1) To Identify Novel APC Substrates. 2) To Assess the Generality of the APC-Cdh1p-Substrate Assembly Pathway. 3) To Determine How D-Box Engagement Stimulates Cdh1p Binding to the APC: 4) To Determine the Roles of Conserved Cdh1p Motifs and of Phosphorylation in APC-Cdh1p-Substrate Assembly. 5) To Determine Whether Disassembly of the APC-Cdh1p-Substrate Complex is an Active Process. 6) To Determine the Function of the MadSp KEN Box in the Spindle Assembly Checkpoint. Degradation of key proteins is essential for cell division. Understanding this degradation is thus important for understanding normal cell proliferation, and how this process goes awry in disease states, particularly cancers.

描述（由申请人提供）：通过有丝分裂进展和退出的关键事件是通过促进复合物（APC；也称为环体）对细胞周期蛋白和其他关键蛋白的泛素依赖性降解。 APC底物包含降解基序，例如破坏框和其泛素化所需的KEN框以及它们与APC激活剂CDC20和CDH1的结合。这两个基序都是有效降解所必需的，但任何一个单独的基序都足以与CDH1P结合。我们提出了一种用于组装APC-CDH1P-SUBSTRATE复合物的途径，其中APC无CDH1P首先结合底物。 CDH1P对底物破坏框的参与刺激了CDH1P与APC的结合，大概是通过CDH1P中的构象变化。当前的研究旨在进一步了解我们对萌芽酵母中APC介导的蛋白水解的理解。特别是，我们希望识别新型的APC底物，了解APC-CDH1P/CDC20P-SUBSTRATE络合物如何组装和拆卸，并了解纺锤体组装检查点如何使用KEN盒子关闭APC介导的蛋白质分析时，当染色体未正确地连接到Mitotic脊柱上时。为了实现这些目标，我提出了以下特定目的：1）识别新型APC底物。 2）评估APC-CDH1P-SUBSTRATE组装途径的通用性。 3）确定D-box参与度如何刺激CDH1P与APC结合：4）确定保守的CDH1P基序的作用以及在APC-CDH1P-SUBSTRATE组装中的磷酸化和磷酸化的作用。 5）确定APC-CDH1P-SUBSTRATE复合物的拆卸是一个活动过程。 6）确定主轴组件检查点中MADSP KEN框的功能。关键蛋白的降解对于细胞分裂至关重要。因此，了解这种降解对于理解正常细胞增殖以及该过程在疾病状态，尤其是癌症中的问题很重要。