The mammalian target of rapamycin (mTOR) signaling pathway integrates both intracellular and extracellular signals and serves as a central regulator of cell metabolism, growth, proliferation and survival. Discoveries that have been made over the last decade show that the mTOR pathway is activated during various cellular processes (eg tumor formation and angiogenesis, insulin resistance, adipogenesis and T-lymphocyte activation) and is deregulated in human diseases such as cancer and type 2 diabetes. These observations have attracted broad scientific and clinical interest in mTOR. This is highlighted by the growing use of mTOR inhibitors [rapamycin and its analogues (rapalogues)] in pathological settings, including the treatment of solid tumors, organ transplantation, coronary restenosis and rheumatoid arthritis. Here, we highlight and summarize the current understanding of how mTOR nucleates distinct multi-protein complexes, how intra-and extracellular signals are processed by the mTOR complexes, and how such signals affect cell metabolism, growth, proliferation and survival. mTOR structure and organization into multi-protein complexes

The mTOR protein is a 289-kDa serinethreonine kinase that belongs to the phosphoinositide 3-kinase (PI3K)-related kinase family and is conserved throughout evolution. The poster depicts an overview of mTOR structural domains. mTOR nucleates at least two distinct multi-protein complexes, mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2)(reviewed by Guertin and Sabatini, 2007).