Amino acid sensory complex proteins in mTORC1 and macroautophagy regulation

Abstract

Autophagy is the highly conserved catabolic process, which enables the survival of a cell under unfavorable environmental conditions. In a constantly changing environment, cells must be capable of dynamically oscillating between anabolism and catabolism in order to maintain cellular homeostasis. In this context, the activity of the mechanistic Target Of Rapamycin Complex 1 (mTORC1) is of major importance. As a central signaling node, it directly controls the process of macroautophagy and thus cellular metabolism. Thereby, the control of mTORC1 is equally crucial as the regulation of cellular homeostasis itself, whereby particular importance is attributed to amino acid sensory proteins. In this review, we describe the recent findings of macroautophagy and mTORC1 regulation by upstream amino acid stimuli in different subcellular localizations. We highlight in detail which proteins of the sensor complexes play a specific role in this regulation and point out additional non-canonical functions, e.g. in the regulation of macroautophagy, which have received little attention so far.