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内部细胞反应的调节 外界刺激对于细胞的正常生长、分裂和分化至关重要 细胞和组织。对细胞周期进展的主要控制是由泛素发挥的 介导的蛋白水解作用。例如，染色体分离的开始（后期） 而细胞周期的完成需要多个细胞周期的降解 调节蛋白，如细胞周期蛋白、securin（调节蛋白质的保持） 染色体在一起）和微管运动蛋白。泛素连接酶（或 E3） 这种蛋白水解作用被称为后期促进复合物（APC）。蛋白质是 两种底物识别蛋白 Cdc20 和 Cdh1 靶向 APC，具有活性 分别在有丝分裂晚期和G1期。监管中的一个新兴主题 APC 涉及假底物、本身不是 APC 的蛋白质的作用 底物，但与底物竞争通过 Cdc20 和 Cdh1 结合 APC 底物中发现的 Destruction Box 和 KEN Box 序列。 Acm1 是最近- 在芽殖酵母中鉴定出 APCCdh1 的假底物抑制剂。除了一个 毁灭盒和 KEN 盒，Acm1 包含一个新颖的图案，有助于其 与 Cdh1 相互作用。 Acm1 也受到泛素介导的蛋白水解作用，两者均通过 APCCdc20 在有丝分裂期间以及在整个细胞周期中通过一种未识别的机制，以及 通过磷酸化保护免受这两种途径的影响。 为了进一步了解通过假底物抑制来调节 APC， 我们提出以下具体目标： 1) 确定 Acm1 基序和负责 Acm1 的细胞途径 降解以及 Acm1 磷酸化在保护其免于降解中的作用。 2) 使用遗传筛选来鉴定新型人类和酵母假底物 APC 抑制剂。 我们还将进一步探讨脊椎动物Emi1蛋白发挥作用的机制 假底物抑制剂。