New insights into MTORC1 amino acid sensing and activation

The mechanistic target of rapamycin complex 1 (MTORC1) is an evolutionarily conserved eukaryotic Ser/Thr kinase that works as a master transducer of multiple cellular inputs involving growth factor sensing, and amino acid and ATP availability. Nutrient-rich conditions promote MTORC1 activation, which in turn leads to the stimulation of various anabolic processes such as protein and lipid synthesis, and cellular growth. Similarly, once activated MTORC1 also inhibits certain catabolic pathways such as macroautophagy/autophagy. In this regard, it is no surprise that a common feature in many cancer types is the deregulation of MTORC1 signaling (1). The close relationship between MTORC1 and cancer highlights the importance for a better understanding of the regulatory pathways by which MTORC1 is activated.