Gene heats up obesity research.Researchers have identified a gene apparently used by cells to convert excess calories to heat. The discovery may offer insight into why some people stay trim on the same diet that induces weight gain in others. The gene, described in the March Nature Genetics, encodes a molecule that researchers have dubbed uncoupling protein A uncoupling protein is a proton channel which disrupts the gradient before it can be used to provide the energy for oxidative phosphorylation.[1] There are five types known in mammals:
"UCP2 may be a major player in the body's energy metabolism Energy metabolism Energy metabolism, or bioenergetics, is the study of energy changes that accompany biochemical reactions. Energy sustains the work of biosynthesis of cellular and extracellular components, the transport of ions and organic chemicals against ," says obesity researcher Craig H. Warden of the University of California, Davis The University of California, Davis, commonly known as UC Davis, is one of the ten campuses of the University of California, and was established as the University Farm in 1905. . The protein, explains Warden, directs a cellular biochemical reaction that converts calories to simple heat rather than to ATP ATP: see adenosine triphosphate. ATP in full adenosine triphosphate Organic compound, substrate in many enzyme-catalyzed reactions (see catalysis) in the cells of animals, plants, and microorganisms. , the prime energy-storage molecule that powers cells' activities. As a result, cells with a more active UCP2 gene may have to burn additional calories to meet their energy needs, which would leave fewer excess calories to be stored as fat. The tantalizing tan·ta·lize tr.v. tan·ta·lized, tan·ta·liz·ing, tan·ta·liz·es To excite (another) by exposing something desirable while keeping it out of reach. hypothesis raised by the discovery of this gene is that individual differences in UCP2 and its regulation may determine a person's overall metabolic rate and consequent propensity toward obesity. The UCP2 gene was discovered independently by Warden's research group and a team led by Daniel Ricquier of the National Center for Scientific Research in Meudon, France. The groups joined a third team, led by Richard S. Surwit of Duke University Medical Center in Durham, N.C., to investigate the new gene further. The scientists found that the gene is active in many types of cells, including fat and immune cells. Surwit speculates that infections trigger increased UCP2 activity in immune cells and that the heat generated produces fevers. The researchers also discovered that dietary fat regulates the activity of the UCP2 gene. When they fed mice a high-fat diet high-fat diet A diet rich in fats, often saturated–animal or tropical oils—fats Adverse effects Arthritis, CA, vascular disease, DM, HTN, obesity, stroke. See Fat, Fatty acids, Saturated fat acis, Cf Low-fat diet. , the gene's activity increased. Moreover, the investigators found that the diet-induced UCP2 activity varies among strains of mice with different propensities toward obesity. Mice that become obese when placed on a high-fat diet seem to make less UCP2 than do the strains that resist obesity, the researchers report. While there is so far no direct evidence linking the UCP2 gene to human obesity, researchers have started to contemplate obesity therapies involving the gene. Surwit contends that most human obesity is the result of a low metabolic rate, and he suggests that this defect might one day be corrected by administration of a drug that increases the activity of the UCP2 gene. |
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