Obesity in humans and rodents is characterized by mitochondrial dysfunction, but what connects obesity and mitochondrial damage? The small GTPase RalA, according to a report in Nature Metabolism.

The report’s authors observed increased RalA expression and activity in inguinal white adipose tissue (iWAT) during the development of obesity in mice fed a high-fat diet (HFD), prompting them to create adipocyte-specific Rala knockout (RalaAKO) mice for further studies. These mice, when fed a HFD, were protected against weight gain, glucose intolerance and hepatic steatosis. A closer look revealed an increase in energy expenditure alongside increased mitochondrial oxidative phosphorylation, reflected by increased fatty acid oxidation, in primary adipocytes from RalaAKO mice compared with wild-type primary adipocytes.