mTOR

mTOR (mechanistic Target of Rapamycin) is a serine/threonine protein kinase that forms two distinct multi-protein complexes, mTORC1 and mTORC2, each with different upstream activators and downstream targets. mTORC1 integrates signals from amino acids, growth factors, energy status, and oxygen availability to control anabolic processes including protein synthesis via phosphorylation of S6K1 and 4E-BP1, lipid biogenesis, and nucleotide synthesis. When nutrients are abundant, mTORC1 promotes cell growth and suppresses autophagy; during nutrient scarcity or stress, mTORC1 is inhibited, triggering catabolic recycling pathways. mTORC2 regulates cytoskeletal organisation, cell survival via Akt phosphorylation, and metabolic reprogramming. The mTOR pathway is a key target in longevity research because its inhibition by rapamycin extends lifespan in multiple organisms. In peptide research, growth hormone secretagogues like CJC-1295 and Ipamorelin activate mTOR signalling indirectly through elevated IGF-1 levels, promoting muscle protein synthesis and tissue repair.