Fat-busting protein

Obesity is increasing in prevalence worldwide and has serious consequences for healthcare providers, but the molecular mechanisms involved in fat accumulation remain poorly understood. In October Nature Medicine, Kyoko Tsukiyama-Kohara and colleagues at McGill University, Montreal, Canada, show that the protein 4E-BP1 can enable white fat (a reserve of energy) to adopt the properties of brown fat (a source of heat generation) and can increase energy expenditure (Nat Med 2001, 7:1128-1131).

The protein 4E-BP1 is an inhibitor of mRNA translation and is highly phosphorylated in the adipose tissue in response to insulin treatments. Tsukiyama-Kohara et al. investigated the biological function of 4E-BP1 by disrupting its gene (Eif4ebp1) in the mouse. They found that Eif4ebp1^–/– mice had smaller white fat pads than wild-type animals, and an increased metabolic rate. The white fat present in these mice had taken on the properties normally associated with brown...