TOR signaling is responsible for a cellular reaction towards nutrient and energy availability and hypoxia/stress. The mammalian Target Of Rapamycin (mTOR), a serine/threonine kinase, is the central regulator that consists in two different complexes: a rapamycin-sensitive complex (mTORC1) consisting of mTOR, Raptor and GbetaL that regulates mRNA translation, ribosome biogenesis and autophagy and a second rapamycin-insensitive complex (mTORC2) consisting of mTOR, Rictor GbetaL, Sin1 and Protor 1/2 that regulates survival and a cytoskeletal response.
TOR signaling is highly integrated in other signaling pathways that respond to external conditions, such as the insulin-signaling cascade and AMPK signaling.