mTORC1 (Mechanistic Target of Rapamycin Complex 1)

A protein kinase complex that functions as a central cellular nutrient and energy sensor and controls the initiation of protein synthesis. In the context of muscle protein synthesis, mTORC1 activation is the primary signalling event that initiates translation of muscle proteins. L-Leucine is the most potent amino acid activator of mTORC1 — this is the mechanistic basis for leucine's central role in the protein synthesis response to a meal or post-exercise nutrition. mTORC1 is also activated by insulin and growth factors.