SOAT1 and obesity due to melanocortin 4 receptor deficiency: In obesity, there are circulating levels of IL-6 that, when binding to its receptor, induces phosphorylation and activation of the JAK2/STAT3 pathway, which transcriptionally regulates its suppressor, the suppressor of cytokine signaling (SOCS3) (Heinrich et al., 2003), which regulates the signaling generated by JAK/STAT.