ADH5 and obesity due to melanocortin 4 receptor deficiency: Hepatic dysfunction of the denitrosylase GSNOR elevates S-nitrosylation of lysosomal enzymes, disrupts autophagic flux, and promotes insulin resistance in obesity, whereas restoring GSNOR activity or expressing nitrosylation-resistant lysosomal proteins rescues autophagy and improves insulin action [222].