The Dawn of the Age of Amino Acid Sensors for the mTORC1 Pathway

The mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of cell growth that responds to a diverse set of environmental inputs, including amino acids. Over the past 10 years, a number of proteins have been identified that help transmit amino acid availability to mTORC1. However, amino acid sensors for this pathway have only recently been discovered. Here, we review these recent advances and highlight the variety of unexplored questions that emerge from the identification of these sensors. Wolfson and Sabatini describe recent advances in understanding how amino acids are sensed upstream of mTORC1, in particular detailing the discovery of the first amino acid sensors for the pathway. In addition, they analyze how components of the mTORC1 pathway, including the amino acid sensors, are conserved across evolution.