SREBF1 and steatosis: Fourthly, published reports show that events up-stream (i.e., loss of PTEN [15], [16] and LKB1 [17], activation of Akt [18]) and down-stream (i.e., loss of 4E-BP1/2 [19], activation of SREBP1 [20]) of mTORC1 can induce steatosis.