骨骼肌不仅是运动系统的重要组成部分，在人体的代谢调控方面也起着关键的调节作用。骨骼肌的分化发育以及其质量稳态的维持都依赖于成肌细胞的分化和融合。近期研究显示mTOR通路是调控成肌细胞分化的重要信号系统，但具体分子机制尚有待深入。我们预实验发现调控细胞早期内体转运的小G蛋白Rab5是调控成肌细胞分化的新重要分子。进一步实验发现Rab5是mTOR的新相互作用蛋白，且参与调控AKT和mTOR通路活性。在此基础上，我们计划深入研究Rab5和mTOR通路蛋白之间的相互作用网络；探索Rab5对mTOR通路蛋白复合体稳定性及其在细胞内定位的调控作用；并利用肌肉特异性Rab5敲除小鼠来阐明Rab5在体内对mTOR通路活性及肌肉分化再生的调控作用。我们的研究将有助于明确成肌细胞分化的分子机理，加深对骨骼肌稳态调控规律的理解，为开发肌肉相关疾病治疗的新方法提供理论基础。

Skeletal muscle plays important roles in both physical performance and metabolism regulation. Muscle development and homeostasis rely on the myoblast differentiation and fusion. Recent studies revealed that mTOR pathway is critical for regulating myogenic differentiation, but the underlying mechanism is elusive. Here we found that Rab5 is important for myoblast differentiation. Further study showed that Rab5 is a novel binding partner of mTOR and is involved in modulating AKT and mTOR pathway activity. We aim to further identify the interaction network between Rab5 and mTOR pathway proteins; to explore the potential roles of Rab5 in regulating mTOR complex stability and cellular localization; and to reveal the in vivo roles of Rab5 in modulating mTOR pathway, muscle differentiation, and muscle regeneration. Our study will not only help to delineating the mechanism underlying myogenic differentiation and muscle homeostasis, but also provide theoretic basis for developing new treatment of muscle-related diseases.