Mechanistic target of rapamycin complex (mTORC) (mTORC)

The mechanistic target of rapamycin (mTOR) is a conserved serine/threonine kinase that functions as a central hub for integrating environmental cues to regulate cellular growth and metabolism [Saxton & Sabatini, 2017]. It operates within two structurally and functionally distinct multi-protein complexes: mTORC1 and mTORC2 [UniProt P42345]. mTORC1 is activated by growth factors and nutrients to promote anabolic processes like protein and lipid synthesis while suppressing catabolic processes like autophagy [StatPearls, 2023]. mTORC2 primarily responds to growth factors and regulates cell survival, metabolism, and the cytoskeleton by phosphorylating members of the AGC kinase family, including Akt [PubMed: 28235197]. Aberrant mTOR signaling is implicated in a wide range of pathologies, including cancer, metabolic disorders, and neurodegeneration, making these complexes high-priority therapeutic targets [NCI Drug Dictionary]. Therapeutic strategies involve rapalogs, which are allosteric inhibitors of mTORC1, and newer ATP-competitive inhibitors that target the kinase domain of both complexes to achieve more complete pathway suppression [PubChem]. Clinical use of mTOR inhibitors is often limited by feedback loops and side effects such as hyperglycemia and immunosuppression [PubMed: 21115608]. Ongoing research focuses on dual PI3K/mTOR inhibitors and third-generation molecules to overcome resistance [Nature, 2016].

Other names

mTORC1mTORC2mTOR complexesMammalian target of rapamycin complexFRAP complexRAFT1 complex

Drugs targeting mTOR complexes act either as allosteric inhibitors (rapalogs) that primarily disrupt mTORC1 function or as ATP-competitive inhibitors that block the catalytic activity of both mTORC1 and mTORC2.