Lysosomal catch-and-release controls mTORC1

Rag GTPases facilitate mTORC1 activation by recruiting it to Rheb at the lysosome when amino acids are abundant. A study now shows that the amino acid-induced change in the GTP/GDP-binding state of the Rag heterodimer paradoxically increases its dynamic release from the Ragulator at the lysosome and may limit mTORC1 activation.