Figure 1.

mTORC1 signaling pathway. mTORC1 is a serine/theronine kinase complex that receives information regarding the nutrient status of the cell and orchestrates a pro-survival response to the conditions in the tumor microenvironment. In response to low glucose levels, intracellular AMP concentrations increase, leading to the activation of AMPK, which negatively regulates mTORC1 through activation of the TSC complex. In response to amino acid deprivation, the Rag-GTPases are unable to associate with mTORC1, preventing its activation. mTORC1 inhibition limits cellular energy use by regulating cell size and proliferation through S6K and 4EBP1, respectively. Additionally, mTORC1 inhibition induces autophagy to produce an alternative energy source.