Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.
The mechanistic target of rapamycin complex 1 (mTORC1) is a master controller of cell growth and metabolism which integrates diverse bio-signaling inputs to coordinate various fundamental biological processes. Amino acids, especially leucine, arginine and glutamine, signal to mTORC1 activation. Classically, Rag GTPases play a crucial role in amino acids-induced mTORC1 activation in the lysosome and Golgi apparatus. More recently, multiple amino acid sensors have been identified and most of them indirectly associate with Rag GTPases. As a result, the mechanistic details on how amino acids are sensed and activate mTORC1 are rapidly evolving. This review discusses current understanding of mTORC1 activation and provides a brief and up-to-date narrative on the progress of amino acid sensors regulating mTORC1 activation.