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.

The gene RICTOR is located on chromosome 5 at 5p13.1 with a sequence length of 5440 bp, oriented on the minus strand. The translated RICTOR protein contains 1709 amino acids and is present in the cytosol. RICTOR contains few conserved regions and function domains of RICTOR have yet to be observed. However, using liquid chromatography-tandem mass spectrometry analysis, 21 phosphorylation sites were identified on RICTOR. Of these sites, T1135 has been shown to undergo growth factor-responsive phosphorylation via S6K1.

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.

FoxO transcription factors can activate expression of RICTOR. FoxO has been shown to inhibit mTORC1, while activating Akt through RICTOR elevation.