Chewing the Fat--ACC and Energy Balance

Working out the intricate pathways that regulate energy balance has kept biologists busy for decades. The part played by the hypothalamus and fat cells in energy balance has been well worked out, but the importance of intracellular intermediates such as malonyl CoA has been less well defined. In their Perspective, Ruderman and Flier discuss new findings in knockout mice deficient in one isoform of the enzyme ACC, which synthesizes malonyl CoA ( Abu-Elheiga et al.). The new work shows that malonyl CoA, specifically synthesized by this ACC isoform, is an important regulator of fatty acid oxidation, and that its absence results in mice that massively overeat yet never gain weight.