FIGURE 2.

mTOR-dependent and mTOR-independent signaling pathways. In the mTOR-dependent signaling pathways, AKT/mTOR/SREBPs activate SREBPs in cancer cells. Numerous protein molecules can directly or indirectly (through AKT) act on mTOR, thereby regulating the activation of SREBPs. In the PI3K/AKT/mTOR/SREBP1 pathway, mTOR further enhances AKT signaling in melanoma cells through positive feedback. In the mTOR-independent pathway, HBXIP and PD-L1 act directly on SREBP1 and promote its activation. Mutation of the R132H site of IDH1, loss of p53, and FDXR all promote the activation of SREBP1 and SREBP2.