[7] RPTOR is highly expressed in skeletal muscle and is somewhat less present in brain, lung, small intestine, kidney, and placenta tissue.

[9][10] RPTOR encodes part of a signaling pathway regulating cell growth which responds to nutrient and insulin levels.

[7] RPTOR is a 150 kDa mTOR binding protein that is part of the mammalian target of rapamycin complex 1 (mTORC1).

[13] AMPK causes phosphorylation in the event of nutrient starvation and promotes 14-3-3 binding to raptor, which downregulates the mTORC1 complex.

Mutations in the PTEN tumor suppressor gene are the best known genetic deficiencies in cancer which affect mTOR signaling.

These mutations are frequently found in a very large variety of cancers, including prostate, breast, lung, bladder, melanoma, endometrial, thyroid, brain, and renal carcinomas.

In turn, active PDK1, along with mTORC1, phosphorylates S6K in the part of the mTOR pathway which promotes protein synthesis and cell growth.

Studies with C. elegans, fruitflies, and mice have shown that the lifespan of the organism is significantly increased by inhibiting mTORC1.

Astrin recruits RPTOR to stress granules, inhibiting mTORC1 association and preventing apoptosis induced by mTORC1 hyperactivation.

RPTOR could be valuable in the prediction and prognosis of pituitary adenoma due to this correlation between protein expression and the growth and invasion of the tumor.