Signaling Pathways Regulating Proteolysis in Innervated Muscle

调节受神经支配肌肉蛋白水解的信号通路

• 批准号: 0542355
• 负责人: Lewis Jacobson
• 金额: --
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-15 至 2011-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0542355&HistoricalAwards=false
• 关键词: Signaling; Pathways; Regulating; Proteolysis; Innervated

The long-range objective of this project is to understand the external and intramuscular signals and signal-transduction networks that regulate protein degradation in muscle. Previous studies in this laboratory have identified and characterized the proteasome-mediated degradation induced by starvation or functional denervation and the non-proteasomal degradation induced by Fibroblast Growth Factor (FGF) signaling via a Ras-MAP kinase cascade, and shown a role of Insulin-like Growth Factor receptor signaling in opposing FGF-promoted degradation. These studies made it clear not only that protein degradation in muscle responds to multiple external and autocrine signals and is mediated by multiple proteolytic mechanisms, but also that the state of protein catabolism may be determined by the balance between opposing signals rather than by the intensity of a single signal. This proposal focuses on elucidating the observations that degradation of transgene-coded reporter proteins in muscles of Caenorhabditis elegans is negatively regulated by a Transforming Growth Factor Beta (TGF-beta) receptor, and is promoted by excess signal from a calcium-calmodulin dependent protein kinase (CaMKII). The methodologies used are primarily those of genetics (particularly suppression and epistasis analysis), biochemistry (measurement of reporter proteins and molecular correlates of signaling) and molecular biology. Potentially novel signaling pathways will be elucidated, effectors downstream of the TGF-beta receptor and CaM kinase will be characterized, and the relation of these pathways to others in the cell will be explored. The broader impact of this project, in the short-to-medium term, will be to provide a keener understanding of how complex networks of signals and signal-transduction pathways, operating in at least two distinct cell types (neurons and muscles) and possibly a third (hypodermis), are coordinated to regulate protein stability in the target tissue (muscle). There will also be significant educational impacts: Undergraduate researchers will be an integral part of the project team. The senior scientific personnel will make strong efforts to incorporate aspects of C. elegans biology and neuromuscular biology in general into undergraduate courses they teach (Genetics, Introductory Biology) and into other undergraduate courses (Developmental Biology, Cell Biology). Modules using C. elegans as a model for insulin signaling and lipid metabolism are incorporated into workshops for high-school teachers and live C. elegans are provided for K-12 school visits. In the longer term, the impact of this project on clinically important issues of muscle health could become substantial, since the catabolism of muscle proteins is important both for normal adaptive physiology and for a variety of pathological states.

该项目的长期目标是了解肌肉中调节蛋白质降解的外部和肌肉内信号和信号转导网络。本实验室之前的研究已经确定并描述了由饥饿或功能性去神经支配诱导的蛋白酶体介导的降解，以及通过Ras-MAP激酶级联由成纤维细胞生长因子（FGF）信号诱导的非蛋白酶体降解，并显示了胰岛素样生长因子受体信号在对抗FGF促进的降解中的作用。这些研究表明，肌肉中的蛋白质降解不仅响应多种外部和自分泌信号，并由多种蛋白质水解机制介导，而且蛋白质分解代谢的状态可能由相反信号之间的平衡决定，而不是由单一信号的强度决定。本研究的重点是阐明秀丽隐杆线虫肌肉中转基因编码报告蛋白的降解受转化生长因子β (tgf - β)受体的负调控，并由钙钙调蛋白依赖性蛋白激酶（CaMKII）的过量信号促进。所使用的方法主要是遗传学（特别是抑制和上位分析）、生物化学（报告蛋白和信号相关分子的测量）和分子生物学。潜在的新信号通路将被阐明，tgf - β受体和CaM激酶下游的效应物将被表征，这些通路与细胞中其他通路的关系将被探索。在中短期内，该项目的广泛影响将是提供对复杂的信号网络和信号转导途径的更敏锐的理解，这些信号网络和信号转导途径在至少两种不同的细胞类型（神经元和肌肉）中运作，可能还有第三种（皮下组织），它们是如何协调调节目标组织（肌肉）中的蛋白质稳定性的。这也将对教育产生重大影响：本科生研究人员将成为项目团队不可或缺的一部分。高级科学人员将努力将秀丽隐杆线虫生物学和神经肌肉生物学的各个方面纳入他们所教授的本科课程（遗传学，生物学入门）和其他本科课程（发育生物学，细胞生物学）。使用秀丽隐杆线虫作为胰岛素信号和脂质代谢模型的模块被纳入高中教师的研讨会，并为K-12学校访问提供活的秀丽隐杆线虫。从长远来看，该项目对肌肉健康的临床重要问题的影响可能会变得实质性，因为肌肉蛋白的分解代谢对正常的适应性生理和各种病理状态都很重要。