PERM1 and obesity due to melanocortin 4 receptor deficiency: Combining our data with existing reports,46 we suggest that phosphorylation of PERM1 most likely coordinates CaMK2-MEF2 signaling and AMPK-PGC-1α signaling to synergistically promote slow fiber development and mitochondrial production in skeletal muscles, providing potential therapeutic targets for obesity-related metabolic diseases.