Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.
Cancer Research UK Edinburgh Centre, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK.
J Cell Biol. 2021 May 3;220(5). doi: 10.1083/jcb.202004010.
The mammalian target of rapamycin complex 1 (mTORC1) integrates mitogenic and stress signals to control growth and metabolism. Activation of mTORC1 by amino acids and growth factors involves recruitment of the complex to the lysosomal membrane and is further supported by lysosome distribution to the cell periphery. Here, we show that translocation of lysosomes toward the cell periphery brings mTORC1 into proximity with focal adhesions (FAs). We demonstrate that FAs constitute discrete plasma membrane hubs mediating growth factor signaling and amino acid input into the cell. FAs, as well as the translocation of lysosome-bound mTORC1 to their vicinity, contribute to both peripheral and intracellular mTORC1 activity. Conversely, lysosomal distribution to the cell periphery is dispensable for the activation of mTORC1 constitutively targeted to FAs. This study advances our understanding of spatial mTORC1 regulation by demonstrating that the localization of mTORC1 to FAs is both necessary and sufficient for its activation by growth-promoting stimuli.
哺乳动物雷帕霉素靶蛋白复合物 1(mTORC1)整合有丝分裂原和应激信号,以控制生长和代谢。氨基酸和生长因子激活 mTORC1 涉及复合物向溶酶体膜的募集,并进一步得到溶酶体分布到细胞边缘的支持。在这里,我们表明溶酶体向细胞边缘的易位将 mTORC1 带入与焦点粘连(FA)的接近处。我们证明 FA 构成离散的质膜枢纽,介导生长因子信号和氨基酸进入细胞。FA 以及溶酶体结合的 mTORC1 向其附近的易位,有助于细胞外周和细胞内 mTORC1 活性。相反,溶酶体向细胞边缘的分布对于持续靶向 FA 的 mTORC1 的激活是可有可无的。这项研究通过证明将 mTORC1 定位到 FA 对于其被促生长刺激激活是必要且充分的,从而推进了我们对空间 mTORC1 调节的理解。