Fig. 2
From: Causal relationship between insulin resistance and sarcopenia
Cell stimulation by insulin and amino acids is the main factor that affects intracellular protein synthesis and increases intracellular perfusion of amino acids. Amino acids and insulin increase the activation level of mTORC1 via different pathways. Insulin relieves the inhibitory effect of the TSC on mTORC1 primarily by increasing the activation level of AKT, while amino acids can directly activate mTORC1. An increase in the activation level of mTORC1 subsequently promotes the synthesis of myocyte proteins. Red arrows represent inhibitory effects, and blue arrows represent activating effects. PIP3 phosphatidylinositol 3,4,5-triphosphate