mTOR (mechanistic target of rapamycin) is a central regulator of cell growth, proliferation, metabolism, and survival. It is a serine/threonine kinase that integrates signals from nutrients, growth factors, and cellular energy status.
mTOR promotes protein synthesis and cell growth by activating downstream targets such as S6 kinase and 4E-BP1. In cancer, this pathway can become hyperactivated, leading to uncontrolled cell proliferation.