Mechanistic target of rapamycin complex 1 and mechanistic target of rapamycin complex 2 (mTORC1 and mTORC2)

Mechanistic target of rapamycin complex 1 (mTORC1) and mechanistic target of rapamycin complex 2 (mTORC2) are two structurally and functionally distinct protein complexes centered on the mTOR kinase[1][2][3][5][9]. mTORC1, consisting of mTOR, Raptor, mLST8, PRAS40, and DEPTOR, senses cellular nutrient and energy status to regulate protein synthesis, autophagy, and cell growth. It is acutely sensitive to inhibition by the drug rapamycin[1][3]. mTORC2, in contrast, contains mTOR, Rictor, mSIN1, Protor, mLST8, and DEPTOR, and is primarily involved in regulating cell survival, metabolism, and cytoskeletal organization, notably via Akt phosphorylation; it is not directly inhibited by rapamycin[1][5][7]. Both complexes play critical roles in developmental signaling, metabolism, and disease, and dysfunction of mTORC1 or mTORC2 is implicated in cancer, metabolic disorders, neurodegeneration, cardiovascular and immune diseases[3][5]. Numerous clinically approved drugs target mTOR complexes for immunosuppression and cancer therapy, but adverse metabolic and immunological effects are common due to their central role in cellular function[6][3].

Other names

mTOR Complex 1mTOR Complex 2Mammalian target of rapamycin complex 1Mammalian target of rapamycin complex 2Rapamycin-sensitive mTOR complex (for mTORC1)Rapamycin-insensitive companion of mTOR complex (for mTORC2)

mTORC1 inhibitors (rapalogs): Inhibit mTORC1 kinase activity, reduce phosphorylation of downstream effectors, suppress protein synthesis and cell growth[6][1]. Dual mTORC1/mTORC2 inhibitors: Block both complex activities, more completely suppressing mTOR signaling. Allosteric inhibition (via FKBP12-rapamycin binding for mTORC1)[4]