TLR4 and Insulin resistance: PERK promotes insulin resistance by (i) activating JNK and p38 MAPK [49, 313]; (ii) phosphorylating FOXO on S298, a site which is not phosphorylated by Akt and whose phosphorylation counteracts the effects of Akt [49]; (iii) downregulating expression of the serine protease prostatin (PRSS8), which regulatorily degrades TLR4 [314]; (iv) inducing the pseudokinase tribble 3 (TRB3), which is increased in the liver of obese mice and humans and contributes to hepatic insulin resistance [49, 315].