RABL2 Is Required for Hepatic Fatty Acid Homeostasis and Its Dysfunction Leads to Steatosis and a Diabetes-Like State

Fatty liver, or hepatic steatosis, is an alarmingly common pathology in western societies, in large part because if left unheeded, it can lead to life-threatening forms of nonalcoholic fatty liver disease, including nonalcoholic steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. As such, it is essential that we attain a greater understanding of the pathways that control energy partitioning in the liver and ultimately how they are impacted by environmental factors. Here, we define the essential requirement for a member of the Ras-related protein in the brain (RAB)-like (RABL) clade of small GTPases, RABL2, in fatty acid metabolism including in microtubule-associated mitochondrial movement within the liver. RABL2 dysfunction, even in mice fed a low-fat chow diet, leads to retarded hepatic mitochondria movement associated with and a cascading phenotype of interrelated metabolic defects reminiscent of a type 2 diabetic state: hepatic steatosis, insulin resistance, glucose intolerance, and adu...