FK506-binding protein 12–mechanistic target of rapamycin complex 1 (FKBP12–mTORC1)

The FK506-binding protein 12–mechanistic target of rapamycin complex 1 (FKBP12–mTORC1) is a critical signaling assembly that regulates cellular growth and metabolism in response to environmental cues (Source: UniProt P42345). FKBP12 (FKBP1A) is an immunophilin that serves as an obligatory cofactor for the action of rapamycin and its analogs, known as rapalogs (Source: UniProt P62942). When a rapalog enters a cell, it binds to FKBP12, and this drug-protein complex then physically associates with the FKBP12-Rapamycin Binding (FRB) domain of the mTOR kinase within the mTORC1 complex (Source: PubMed 7738005). This interaction acts as a molecular glue, creating a ternary complex that allosterically inhibits the kinase activity of mTORC1 toward its substrates, such as p70S6K and 4E-BP1 (Source: PubMed 21685886). mTORC1 is a master regulator of cellular metabolism, growth, and survival, integrating signals from nutrients, energy levels, and growth factors (Source: UniProt P42345). Dysregulation of this complex is a hallmark of various pathologies, including cancer, tuberous sclerosis complex, and lymphangioleiomyomatosis (Source: PubMed 19143330). Therapeutically, modulating this complex is essential for preventing organ transplant rejection and treating specific solid tumors (Source: FDA Label, Rapamune). However, chronic inhibition can lead to metabolic side effects like hyperglycemia and hyperlipidemia due to the complex's central role in nutrient sensing (Source: PubMed 22560223).

Other names

FKBP12-mTORC1 complexFKBP1A-mTORC1 complexRapamycin-FKBP12-mTOR complexFKBP12-mTOR complex

Allosteric inhibition of mTORC1 kinase activity via the formation of a ternary complex with FKBP12 and a rapalog, which binds to the FRB domain of mTOR.