TRERF1 and steatosis: Up-regulation of Akt in the absence of significant mTORC1 activity (i.e., +/+ HFD, +/+ HFD-rapa, −/− HFD-rapa) was accompanied by steatosis, but when balanced by high mTORC1 activity (i.e., −/− HFD), no significant lipid accumulated (Figure 8C).