Vms1 is a Novel Protein Critical for Mitochondrial Maintenance

项目摘要 骨骼肌中的线粒体功能障碍具有破坏性后果，包括肌肉萎缩， 运动不耐受和胰岛素抵抗。我们发现一种新的高度保守的蛋白质， 对维持酵母中的线粒体功能和细胞能量稳态至关重要， 哺乳动物细胞我们将这种蛋白质命名为寿命相关线粒体应激反应1 （Lms1）。我们从酵母中获得的数据支持Lms 1招募泛素组分的模型 蛋白酶体系统的线粒体提取受损的蛋白质，并将它们呈递给蛋白酶体， 降解本研究的目的是确定Lms 1的功能和作用机制， 使用培养的肌肉细胞和Lms 1敲除小鼠的骨骼肌。具体目标1和2， 跨越K99和R 00阶段，候选人将研究Lms 1在培养的肌肉细胞中的作用。 目标1的研究将确定哺乳动物Lms 1是否招募泛素蛋白酶体系统， 线粒体作为线粒体蛋白质质量控制系统的一部分。目标2中的研究将确定 在肌细胞中观察到的Lms 1缺失的线粒体缺陷的性质。完成子- 在K99阶段提出的目标将为候选人提供蜂窝方面的培训， 独立完成R 00阶段所需的分子生物学。对于具体目标3和4， 候选人将确定Lms 1在哺乳动物有机体水平上的作用。对于目标3（K99阶段）， 候选人将检查Lms 1基因敲除小鼠心肌线粒体功能障碍，并开始 骨骼肌的研究。对于目标4（R 00阶段），候选人将检查Lms 1骨骼肌- 用于线粒体功能障碍和包括运动不耐受的后果的特异性敲除小鼠， 肌肉萎缩和胰岛素抵抗目标3中提出的实验将为候选人提供 在R 00期间独立完成目标4所需的线粒体生理学培训 相位总的来说，这些实验试图建立Lms 1在培养的细胞中作用的机制基础。 并将这些发现扩展到小鼠，在那里它们将被测试生理相关性。这些 这些研究将为骨骼肌线粒体的调节提供新的见解。

Project Summary Mitochondrial dysfunction in skeletal muscle has devastating consequences including muscle wasting, exercise intolerance, and insulin resistance. We have discovered that a novel, highly conserved protein is critical for maintenance of mitochondrial function and cellular energy homeostasis in yeast and mammalian cells. We have designated this protein Lifespan-associated Mitochondrial Stress-responsive 1 (Lms1). Our data from yeast support a model whereby Lms1 recruits components of the ubiquitin proteasome system to mitochondria to extract damaged proteins and present them to the proteasome for degradation. The purpose of this research is to determine the function and mechanism of Lms1 action in skeletal muscle using cultured muscle cells and Lms1 knockout mice. For Specific Aims 1 and 2, which span the K99 and R00 phases, the candidate will investigate the role of Lms1 in cultured muscle cells. Studies in Aim 1 will determine whether mammalian Lms1 recruits the ubiquitin proteasome system to mitochondria as part of a mitochondrial protein quality control system. Studies in Aim 2 will determine the nature of mitochondrial defects observed with Lms1 depletion in muscle cells. Completion of the sub- aims proposed during the K99 phase will provide the candidate with training in aspects of cellular and molecular biology necessary to independently complete the R00 phase. For Specific Aims 3 and 4, the candidate will determine the role of Lms1 at the mammalian organismal level. For Aim 3 (K99 phase), the candidate will examine an Lms1 knockout mouse for mitochondrial dysfunction in heart muscle and begin studies in skeletal muscle. For Aim 4 (R00 phase), the candidate will examine an Lms1 skeletal muscle- specific knockout mouse for mitochondrial dysfunction and consequences including exercise intolerance, muscle wasting, and insulin resistance. Experiments proposed in Aim 3 will provide the candidate with the training in mitochondrial physiology necessary to independently complete Aim 4 during the R00 phase. Collectively, these experiments seek to establish a mechanistic basis for Lms1 action in cultured muscle cells and to extend these findings to mice where they will be tested for physiologic relevance. These studies will provide novel insight into the regulation of mitochondria in skeletal muscle.