Tricking muscles into burning more fat

Exercise forces muscles to burn fat, but how? Researchers at Sanford Burnham Prebys Medical Discovery Institute believe they’ve discovered an instrumental part of the fat-burning process—a finding that could inspire new treatments for obesity and type 2 diabetes.

The key is a protein called sarcolipin, which is only found in muscles. Sarcolipin binds to a calcium ion transporter called SERCA, which in turn forces muscles to expend more energy so they can move calcium. To get that energy, the body burns more fat, the team discovered. They published the research in the journal Cell Reports.

During the study, they took mice with high levels of sarcolipin and fed them a high-fat diet. The animals didn’t accumulate fat in their muscles, nor did they develop insulin resistance and type 2 diabetes. Animals with no sarcolipin, by contrast, struggled to burn fat.

Obesity researchers have long known obesity hampers the function of sarcolipin. The Sanford Burnham researchers believe their study could provide the insight needed to turn that knowledge into therapies.

“We have more SERCA pumps than we need. Some are bound by sarcolipin, but it only binds around 25 percent of SERCA pumps at any one time. We would need to find drugs that increase efficiency of sarcolipin,” said Sanford Burnham professor and senior author Muthu Periasamy, Ph.D., in a statement. “This strategy could help people with metabolic conditions, as well as those who have difficulty exercising.”

RELATED: 2 proteins show promise as targets for treating obesity

This is the latest in a string of studies that zero in on specific obesity-promoting proteins. In August, an international team of researchers published new findings that may explain why some people have a decreased sensitivity to leptin, the hormone that creates a feeling of fullness. And researchers at the University of Michigan and Vanderbilt University demonstrated how two proteins, MC3R and MC4R, work together to maintain proper energy balance.

Last year, a separate Sanford Burnham team published research focused on natriuretic peptides (NPs), which showed that boosting NP signaling in adipose tissue helps transform unhealthy white fat into energy-burning brown fat.