Duke University Medical Center researchers have identified a new protein that plays a critical role in enabling the heart to respond to such external stimuli as exercise or stress, as well as in the progressive loss of heart function that is heart failure, the researchers said. Their findings, they said, suggest new approaches to prevent or reverse heart failure, which affects two to three million people in the U.S. The team reports its findings in the August 2005 issue of Nature Cell Biology. The study is now available as an advance online publication.