The role of phosphorylation of a COPII coat protein, Sec31 in molecular export

COPII 外壳蛋白 Sec31 磷酸化在分子输出中的作用

• 批准号: 7372401
• 负责人: Pietro De Camilli
• 金额: $ 6.78万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7372401
• 关键词: Accounting; Affect; Age; Aging; Aging-Related Process; Alzheimer' s Disease; Amyotrophic Lateral Sclerosis; Animals; Apoptosis; Apoptotic; Autophagocytosis; Biochemical; Biological Assay; COPII-Coated Vesicles; Capsid Proteins; Carrier Proteins; Cell Aging; Cell Death; Cell Fractionation; Cells; Clathrin; Co-Immunoprecipitations; Cytoplasm; Data; Defect; Degradation Pathway; Disease; Dissociation; Endoplasmic Reticulum; Endoplasmic Reticulum Degradation Pathway; Exhibits; Failure; Fluorescence Recovery After Photobleaching; Functional disorder; GTPase-Activating Proteins; Golgi Apparatus; Guanine Nucleotide Exchange Factors; Half-Life; Huntington Disease; Impairment; In Vitro; Kinetics; Lead; Life; Maps; Mediating; Membrane; Molecular; Monitor; Monomeric GTP-Binding Proteins; Organelles; Parkinson Disease; Pathway interactions; Phosphorylation; Phosphorylation Site; Phosphotransferases; Protein Denaturation; Protein Dephosphorylation; Protein Export Pathway; Proteins; Regulation; Role; Site; Stress; System; Testing; Thinking; Tissues; Vesicle; Western Blotting; Work; Yeasts; age related; aged; base; biological adaptation to stress; cell age; cell growth; cytokine; in vivo; intracellular protein transport; klotho protein; mimetics; mutant; prevent; protein degradation; protein misfolding; protein transport; receptor; senescence; success; trafficking

DESCRIPTION (provided by applicant): A decrease in the export of nascent proteins from the endoplasmic reticulum with aging may shorten cell life by two mechanisms: 1) initiation of ER stress responses, leading to enhanced apoptosis, and 2) secretion and trafficking of proteins, such as cytokines and their receptors that are required for cell growth and differentiation. A hallmark of the aging processing is the accumulation of inactive proteins that have cleared by cellular degradation systems. This pool is formed by both proteins that have been misfolded and those that have been inactivated and reached the end of their biologic half-lives. Three general mechanisms could account for the accumulation of such proteins: 1) increased misfolding, 2) enhanced protein denaturation and 3) decreased function in degradation pathways. We propose that dysfunction of protein export from the endoplasmic reticulum during aging leads to protein accumulation in the ER, protein misfolding, stimulation of ER stress responses, and enhanced apoptotic cell death. This proposal will examine the role of COPII coat proteins in the age-dependent accumulation of inactive cellular proteins. Molecular export from the ER is thought to be mediated by COPII vesicles. It has been shown that an essential COPII coat component, Sec31 in yeast, is phosphorylated and its phosphorylation has been implicated in COPII vesicle budding. However, the molecular mechanisms, including the phosphorylation sites and the kinases for this phosphorylation, are unknown. Hypothesizing that the phosphorylation-dephosphorylation cycle of the coat components of COPII vesicles may regulate molecular export from the ER, we recently discovered the phosphorylation of mammalian Sec31. In this proposal, we will determine: 1) whether the cycle of phosphorylation-dephosphorylation of mammalian Sec31 regulates protein export from the ER, 2) whether trafficking of the klotho protein, as well as other cargoes, are affected by dephosphorylation of Sec31, and 3) whether there are age-associated changes in the phosphorylation of Sec31, which may correlate with potential age-related impairment of the early secretory pathway. The success of this study will lead to a further understanding of the molecular mechanisms of aging, which may contribute to cures for age-related diseases.

描述(申请人提供)：随着年龄的增长，内质网新生蛋白质的出口减少可能通过两种机制缩短细胞寿命：1)启动内质网应激反应，导致细胞凋亡增加；2)蛋白质的分泌和运输，如细胞生长和分化所需的细胞因子及其受体。衰老过程的一个标志是积累了被细胞降解系统清除的非活性蛋白质。这个池是由错误折叠的蛋白质和那些已经失活并达到生物半衰期结束的蛋白质形成的。有三种机制可以解释这类蛋白质的积累：1)错误折叠增加，2)蛋白质变性增强，3)降解途径功能减弱。我们认为，衰老过程中内质网蛋白输出功能障碍导致内质网蛋白积聚，蛋白质错误折叠，刺激内质网应激反应，促进细胞凋亡。这项建议将研究COPII外壳蛋白在依赖年龄积累的非活性细胞蛋白中的作用。内质网的分子输出被认为是由COPII囊泡介导的。研究表明，酵母菌中一个重要的COPII衣壳成分Sec31是磷酸化的，它的磷酸化与COPII囊泡的萌发有关。然而，这种磷酸化的分子机制，包括磷酸化位点和磷酸化的激酶，尚不清楚。假设COPII囊泡外壳成分的磷酸化-去磷酸化循环可能调节内质网的分子输出，我们最近发现了哺乳动物Sec31的磷酸化。在这个方案中，我们将确定：1)哺乳动物Sec31的磷酸化-去磷酸化循环是否调节内质网的蛋白质输出，2)Klotho蛋白以及其他货物的运输是否受到Sec31去磷酸化的影响，以及3)Sec31的磷酸化是否存在年龄相关的变化，这可能与早期分泌途径的潜在年龄相关损害有关。这项研究的成功将有助于进一步了解衰老的分子机制，这可能有助于治疗与年龄相关的疾病。