CRAIG WARDEN Assistant professor of pediatrics "Energy Expenditure Genes" Two complex traits -- body temperature and weight -- are influenced by the partitioning of calories between alternative pathways for energy storage and expenditure. While there have been many hypotheses about the molecular bases for energy expenditure, the recent discovery of regulated mitochondrial uncoupling proteins (UCPs) that are present in many tissues and species opens up new possibilities. Because uncoupling proteins play a key role in the production of adenosine triphosphate (ATP) -- an important carrier of chemical energy in living organisms -- UCP activity could increase energy expenditure through increased heat loss, with a consequent decrease in body weight. Warden will emphasize the importance to human disease and basic biology of regulated energy expenditure. He will present recent data on the role of the uncoupling proteins in human obesity and plant energy expenditure. He also will suggest possible biological roles that may be played uncoupling proteins if they are present in all plants and animals, including cold-blooded animals. Symposium: "Obesity Update: Molecular Biology of Energy Regulation and Implications for Treatment and Public Policy" Date and time: Friday, Feb.13, 9 a.m.