Mechanistic target of rapamycin complex 1 nutrient-sensing machinery (mTORC1)

The mechanistic target of rapamycin complex 1 (mTORC1) nutrient-sensing machinery is a central signaling hub that coordinates cellular growth and metabolism in response to environmental and intracellular cues [1.1.1, 1.2.1]. This machinery integrates signals from nutrients (such as amino acids and glucose), energy levels (ATP), and growth factors to regulate the balance between anabolic and catabolic processes [1.2.3, 1.3.2]. At the heart of this system is the mTORC1 complex, which is recruited to the lysosomal surface by the Rag GTPases and the Ragulator complex when nutrients are abundant [1.2.4, 1.3.1]. Specific sensors, including Sestrin2 for leucine and CASTOR1 for arginine, relay nutrient status to the complex, ensuring that cell growth occurs only under favorable conditions [1.3.1, 1.3.2]. Dysregulation of the mTORC1 pathway is implicated in a wide range of human diseases, including cancer, type 2 diabetes, obesity, and neurodegenerative disorders [1.1.1, 1.2.3]. Therapeutic targeting of this machinery primarily involves mTOR inhibitors like rapamycin and its analogs (rapalogs), which are used to treat certain cancers and prevent organ transplant rejection [1.2.1, 1.2.5]. Newer generations of drugs, such as ATP-competitive mTOR inhibitors and dual PI3K/mTOR inhibitors, are being developed to overcome the limitations of rapalogs, such as feedback activation of pro-survival pathways [1.2.5, 1.3.3].

Other names

mTORC1 pathwaymTORC1 signaling pathwayLysosomal nutrient-sensing machineryAmino acid sensing machinery of mTORC1

Inhibition of the mTOR kinase activity through allosteric binding to the FKBP12-rapamycin binding (FRB) domain or competitive inhibition at the ATP-binding site, thereby blocking the phosphorylation of downstream effectors like S6K1 and 4E-BP1.