As discussed in the previous chapter, the mechanistic target of rapamycin (mTOR) is a central regulator of cellular growth, metabolism, and survival. mTOR integrates signals from a variety of upstream pathways and is organized into distinct complexes: mTORC1, mTORC2, mTORC3, and mTORC4, with mTORC1 and mTORC2 being the most extensively studied in relation to growth factor signaling. In this chapter, we will explore the critical signaling pathways associated with the mTOR complexes, their specific signal transductions, and the resulting cellular outcomes. This analysis will provide a comprehensive understanding of how mTOR regulates key cellular processes through its diverse and complex signaling network.