Erk1-/- exhibited a low preference for dietary fatty acids and developed obesity. They also showed higher phosphorylation of MEK, an upstream regulator of ERK1/2 and exhibited high ERK2 phosphorylation, high lipogenesis, and low fatty acid oxidation. Overall, ERK1 and ERK2 have different but key roles in obesity. This evidence concerns the gene MAP2K7 and obesity disorder.