哺乳动物雷帕霉素靶标复合物1（mTORC1）是控制骨骼肌蛋白质合成的关键元件。一般认为在氨基酸中，仅亮氨酸和精氨酸能激活mTORC1。本课题组前期研究发现，一些其它特定氨基酸的缺乏也会影响mTORC1活性，然而其中的机制尚不明确。本项目旨在解析其中机制，完善氨基酸调控mTORC1的机理，并为建立促进猪骨骼肌生长的营养调控技术提供理论依据。项目假设为：猪骨骼肌中，特定氨基酸在T1R1/T1R3的介导下，通过Gαi2/c-Src诱导了mTORC1向溶酶体的移位，促进了亮氨酸及胰岛素对mTORC1的活化。拟通过鉴定T1R1/T1R3与 Gαi2的关系；筛选猪T1R1/T1R3的效应氨基酸；研究T1R1/T1R3介导效应氨基酸对mTORC1移位的影响，及其对亮氨酸和胰岛素诱导mTORC1活化的影响；研究Gαi2及c-Src在T1R1/T1R3诱导mTORC1移位中的作用和机制，来证实该假设。

Mammalian target of rapamycin complex 1(mTORC1) is a crucial element in controlling protein synthesis in skeletal muscle. Among amino acids, only leucine and arginine are commonly considered to active mTORC1.In our previous study, we showed that withdrawal of other amino acids,including glycine, proline, serine and alanine, reduced mTORC1 activation.However, the underlying mechanism until recently remains largely unclear.The aim of this proposed study is to explore this mechanism,and to provide theoretical base for optimalizing nutritional manipulation tactics in regulation of skeletal muscle growth.In this proposed study, we suppose that specific amino acids trigger the translocation of mTORC1 to lysosome via T1R1/T1R3 in a Gαi2/c-Src-dependent manner in porcine skeletal muscle,which promotes leucine or insulin-induced activation of mTORC1. By evaluating the expression and colocalization of T1R1, T1R3 and Gαi2, as well as the effect of amino acids on Gαi2 signaling, interaction between T1R1/T1R3 and Gαi2 will be identified. Then porcine T1R1/T1R3-responded amino acids will be identified by evaluating effect of specific amino acid on Gαi2 signaling. We will also evaluate effect of porcine T1R1/T1R3-responded amino acids on mTORC1 translocation, as well as interaction of T1R1/T1R3-responded amino acids-induced and leucine-induced or insulin-induced mTORC1 activation. At last, the of Gαi2 and c-Src in T1R1/T1R3-induced mTORC1 translocation will be study.This proposed study provide an opportunity to understand the role of T1R1/T1R3 in regulation of mTORC1 translocation. On the basis of this proposed study, the function of porcine T1R1/T1R3 will be realized.