Pseudosubstrate Inhibition of the Anaphase Promoting Complex

后期促进复合物的假底物抑制

• 批准号: 7933644
• 负责人: MARK J SOLOMON
• 金额: $ 33.09万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-24 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7933644
• 关键词: Address; Anaphase; Binding; Boxing; Cell Cycle; Cell Cycle Completion; Cell Cycle Progression; Cell Cycle Proteins; Cell Differentiation process; Chromosomes; Complex; Cyclin-Dependent Kinases; Cyclins; Genetic Screening; Growth; Human; Lysine; Microtubules; Mitosis; Motor; Nature; Pathway interactions; Phosphorylation; Proteins; Proteolysis; Regulation; Relative (related person); Role; Saccharomycetales; Signal Pathway; Stimulus; Testing; Time; Tissues; Ubiquitin-mediated Proteolysis Pathway; Ubiquitination; Yeasts; anaphase-promoting complex; genetic selection; human PTTG1 protein; inhibitor/antagonist; interest; novel; research study; response; ubiquitin ligase

Proper functioning of the cell cycle and its regulation in response to both internal and external stimuli is essential for the normal growth, division, and differentiation of cells and tissues. Major control over cell cycle progression is exerted by ubiquitin- mediated proteolysis. For instance, the initiation of chromosome separation (anaphase) and completion of the cell cycle require the degradation of a number of cell cycle regulatory proteins such as cyclins, securin (which regulates the protein holding chromosomes together), and microtubule motor proteins. The ubiquitin ligase (or E3) for this proteolysis is termed the Anaphase Promoting Complex (APC). Proteins are targeted to the APC by two substrate recognition proteins, Cdc20 and Cdh1, active during late mitosis and in G1, respectively. An emerging theme in the regulation of the APC involves the actions of pseudosubstrates, proteins that are not themselves APC substrates but that compete with substrates for binding to Cdc20 and Cdh1 via the Destruction Box and KEN Box sequences found in APC substrates. Acm1 is a recently- identified pseudosubstrate inhibitor of APCCdh1 in budding yeast. In addition to a Destruction Box and a KEN box, Acm1 contains a novel motif that facilitates its interaction with Cdh1. Acm1 is also subject to ubiquitin-mediated proteolysis, both by APCCdc20 during mitosis and by an unidentified mechanism throughout the cell cycle, and is protected from both pathways via phosphorylation. To further our understanding of APC regulation via pseudosubstrate inhibition, we propose the following Specific Aims: 1) To determine the Acm1 motifs and cellular pathways responsible for Acm1 degradation and the role(s) of Acm1 phosphorylation in protecting it from degradation. 2) To use genetic screens to identify novel human and yeast pseudosubstrate APC inhibitors. We will also further explore the mechanism by which the vertebrate Emi1 protein acts as a pseudosubstrate inhibitor.

细胞周期的正常运作及其对细胞内 和外部刺激是必不可少的正常生长，分裂，和分化， 细胞和组织。细胞周期进程的主要控制是由泛素- 介导的蛋白水解。例如，染色体分离的开始（后期） 细胞周期的完成需要许多细胞周期的降解 调节蛋白如细胞周期蛋白、securin（其调节蛋白质保持 染色体在一起）和微管马达蛋白。泛素连接酶（或E3） 用于这种蛋白水解的蛋白质称为后期促进复合物（APC）。蛋白 通过两种底物识别蛋白Cdc 20和Cdh 1靶向APC， 在有丝分裂晚期和G1期。在监管金融机构方面的一个新主题是， APC涉及假底物的作用，假底物是本身不是APC的蛋白质 底物，但与底物竞争结合Cdc 20和Cdh 1，通过 APC底物中发现的破坏盒和KEN盒序列。ACM 1是一个最近- 在芽殖酵母中鉴定APCCdh 1的假底物抑制剂。除了一 破坏盒和KEN盒，Acm 1包含一个新的主题，有利于其 与Cdh 1的相互作用。acm 1也受到泛素介导的蛋白水解，两者都是通过 APCCdc 20在有丝分裂期间和通过整个细胞周期的未鉴定的机制，和 通过磷酸化保护两种途径。 为了进一步理解APC通过假底物抑制的调节， 我们提出以下具体目标： 1)确定Acm 1基序和负责Acm 1的细胞通路 降解和Acm 1磷酸化在保护其免受降解中的作用。 2)使用遗传筛选来鉴定新的人和酵母假底物APC 抑制剂的 我们还将进一步探索脊椎动物的EST 1蛋白作为 假底物抑制剂。