Enhancement of Protein Breakdown through PKG-mediated Phosphorylation of the Proteasome

通过 PKG 介导的蛋白酶体磷酸化增强蛋白质分解

• 批准号: 9792258
• 负责人: Jordan VerPlank
• 金额: $ 6.16万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9792258
• 关键词: 26S proteasome; Adenylate Cyclase; Affect; Aftercare; Aging; Alzheimer' s Disease; Amyotrophic Lateral Sclerosis; Autophagocytosis; Biochemical; Brain; Catalytic Domain; Cell Aggregation; Cells; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Disease; Disease Progression; Exhibits; FDA approved; Failure; Frontotemporal Dementia; Goals; Heart; Human; Impairment; Investigation; Lysosomes; Mammalian Cell; Mass Spectrum Analysis; Mediating; Methods; Modeling; Modification; Mus; Neurodegenerative Disorders; Parkinson Disease; Peptide Hydrolases; Pharmacology; Phosphodiesterase Inhibitors; Phosphorylation; Phosphotransferases; Physiologic pulse; Physiological; Proteins; Site-Directed Mutagenesis; Soluble Guanylate Cyclase; System; Tauopathies; Testing; Therapeutic; Tissues; Ubiquitin; Ubiquitination; Zebrafish; base; cell type; combat; frontotemporal lobar dementia-amyotrophic lateral sclerosis; genetic regulatory protein; inhibitor/antagonist; misfolded protein; multicatalytic endopeptidase complex; mutant; neuroblastoma cell; novel strategies; overexpression; phosphodiesterase IV; prevent; protein B; protein degradation; proteostasis; proteotoxicity; sildenafil; superoxide dismutase 1; tau mutation

Project Summary / Abstract The ubiquitin proteasome system (UPS) degrades the majority of proteins in mammalian cells and one of its primary functions is to selectively eliminate misfolded, potentially toxic proteins. In the UPS, protein substrates are modified by the attachment of chains of ubiquitin molecules, which target the protein for rapid degradation by the 26S proteasome. It is generally assumed that ubiquitination determines the rate of protein degradation by the UPS, but recent studies have shown that the activity of 26S proteasomes is tightly regulated and can determine rates of protein degradation in cells. Our lab and collaborators recently found that agents that raise cAMP cause the Protein Kinase A-mediated phosphorylation of the 26S subunit Rpn6 and the enhancement of multiple proteasome activities. This modification increases the capacity in cells and mouse brains to degrade misfolded, aggregation-prone proteins (e.g. mutant Tau and SOD1) that cause neurodegenerative diseases. Thus, pharmacological enhancement of proteasome function is an exciting new approach to combat various aging-associated diseases. I recently found that treatments that raise cGMP and activate Protein Kinase G also stimulate proteasome activity and protein degradation in cells. This cGMP-mediated stimulation was not due to Rpn6 phosphorylation, and therefore occurs by a different mechanism than raising cAMP. I am proposing an in-depth investigation to determine 1.) how raising cGMP stimulates proteasome function, 2.) the effect of raising cGMP on the degradation of different types of cell proteins and 3.) whether FDA-approved pharmacological agents that increase cGMP levels (e.g. PDE5 inhibitors) enhance the clearance of mutant proteins that cause Alzheimer’s Disease, Amyotrophic Lateral Sclerosis, Frontotemporal Dementia, and Parkinson’s Disease. These studies should clarify the mechanisms and importance of this new mode of regulating protein degradation and its therapeutic potential.

项目总结/摘要 泛蛋白蛋白酶体系统（UPS）降解哺乳动物细胞中的大多数蛋白质和一种蛋白质 其主要功能之一是选择性地消除错误折叠的、潜在有毒的蛋白质。在UPS中，蛋白质 底物通过泛素分子链的连接而被修饰，泛素分子靶向蛋白质， 由26 S蛋白酶体降解。一般认为，泛素化决定蛋白质的速率， UPS降解，但最近的研究表明，26 S蛋白酶体的活性与UPS降解密切相关。 调节并可以确定细胞中蛋白质降解的速率。我们的实验室和合作者最近发现， 升高cAMP的药物引起蛋白激酶A介导的26 S亚基Rpn 6的磷酸化， 增强多种蛋白酶体活性。这种修饰增加了细胞和小鼠的能力， 大脑降解错误折叠的，易于聚集的蛋白质（例如突变的Tau和SOD 1），这些蛋白质导致 神经退行性疾病因此，药理学增强蛋白酶体功能是一个令人兴奋的新的 采取措施防治各种与衰老有关的疾病。 我最近发现，提高cGMP和激活蛋白激酶G的治疗也能刺激 蛋白酶体活性和蛋白质降解。这种cGMP介导的刺激不是由于Rpn 6 磷酸化，因此通过与升高cAMP不同的机制发生。我建议进行深入的 调查确定1.）cGMP升高如何刺激蛋白酶体功能，2.）提高cGMP的作用 对不同类型的细胞蛋白质的降解和3.）FDA批准的药物 增加cGMP水平的药物（例如PDE 5抑制剂）增强了引起 阿尔茨海默氏病、肌萎缩侧索硬化症、额颞叶痴呆和帕金森氏病。 这些研究应该阐明这种新的蛋白质调控模式的机制和重要性 降解及其治疗潜力。