The amino acid transporter SLC38A9 regulates MTORC1 and autophagy

The mechanistic target of rapamycin (serine/threonine kinase) complex 1 (MTORC1) is a master regulator of macroautophagy (hereafter autophagy) that responds to different environmental nutrients, including amino acids, glucose, and growth factors. The identity of the amino acid-sensing component of the MTORC1 machinery had remained elusive until a lysosomal low-affinity amino acid transporter, SLC38A9 (solute carrier family 38, member 9), was recently characterized as a novel component of the Ragulator-RRAG GTPase complex by 3 independent research groups.