Figure 3.

Schematic representation of the influence of amino acids, nutrients, starvation, low ATP/AMP ratio, and caloric restriction on mTORC1 and autophagy. Amino acid availability inhibits autophagy by inhibiting TSC2/1 and activating Rehb that could facilitate the transport of amino acids into the cell and which, in turn, could activate TORC1 that inhibits ULK-complex (black line). In case of low availability of amino acids, autophagy is activated through the TORC2 complex (black dotted line). Up thick arrow = increase. Akt = protein kinase B; ATP = adenosine triphosphate; 4EBP1 = eIF4E-binding protein-1; PI3K = phosphoinositide 3-kinase; Rheb = Ras homolog enriched in brain; S6 = S6-kinase; TSC1/2 = tuberous sclerosis complex 1/2; ULK (Unc-51 like autophagy activating kinase).