Raptor also known as RPTOR is a component of a signaling pathway that regulates cell growth in response to nutrient and insulin levels. Raptor plays a pivotal role in the mammalian target of rapamycin (mTOR) signaling pathway, which is crucial for regulating cell growth, proliferation, and survival in response to nutrient availability. Specifically, Raptor acts as a scaffold that facilitates interaction between mTOR and substrates, including 4E-BP1, thereby promoting phosphorylation and activation. This interaction is vital for cellular response to nutrient levels, as Raptor-mTOR complex is sensitive to changes in nutrient status, allowing cells to adapt growth and metabolism accordingly. Under nutrient-rich conditions, Raptor enhances mTOR activity, while in nutrient-deprived states, Raptor serves as a negative regulator, inhibiting mTOR signaling to conserve resources.