Rapamycin-insensitive companion of mammalian target of rapamycin (RICTOR) is a protein that in humans is encoded by the RICTOR gene. RICTOR and mTOR are components of a protein complex that integrates nutrient- and growth factor-derived signals to regulate cell growth. RICTOR is a subunit of the mammalian target of rapamycin complex 2 (mTORC2) which contains mTOR, GβL, RICTOR (this protein) and mSIN1. The mammalian target of rapamycin (mTOR) is a highly conserved Ser/Thr kinase that regulates cell growth and proliferation. mTOR may exist as mTOR complex 1 (mTORC1) or mTOR complex 2 (mTORC2). RICTOR is a key component of mTORC2, which, unlike mTORC1, is not directly inhibited by rapamycin. mTORC2, and RICTOR, specifically, has been shown to phosphorylate Akt/protein kinase B (PKB) on SER473. This phosphorylation activates Akt/PKB, where deregulation of Akt/PKB has been implicated in cancer and diabetes. RICTOR and mTORC2 have been shown to play an essential role in embryonic growth and development, perhaps due to the control that mTORC2 exerts on actin cytoskeleton organization. Diseases associated with mutation in the RICTOR gene include foramen magnum meningioma and syringomyelia. Akt/PMB activation is also involved in glucose metabolism and activation of Akt by RICTOR has been shown to mediate glucose and lipid metabolism. Therefore, the influence of RICTOR and mTORC2 on Akt signaling has been associated with insulin resistance and type 2 diabetes.