PKR is also related to obesity and insulin resistance, as its phosphorylation is increased in high-fat diet fed mice, leading to activation of JNK [68] and IKKβ [69], and culminating in serine phosphorylation of IRS-1 and insulin resistance [70]; all these inflammatory features are absent or attenuated in PKR−/− mice [71, 72]. This evidence concerns the gene EIF2AK2 and obesity due to melanocortin 4 receptor deficiency.