As we age or suffer illness, our muscles atrophy. The deterioration of muscle—even slight or gradual—is as common to the human condition as breathing.

Yet despite its everyday nature, scientists know little about what causes skeletal muscles to atrophy, according to a University of Iowa press release. They know proteins are responsible, but there are thousands of possible suspects, and parsing the key actors from the poseurs is tricky.

In a new paper, researchers from the University of Iowa report major progress. The team has identified a single protein, called Gadd45a, and determined that it orchestrates 40 percent of the gene activity that ultimately causes skeletal muscle to atrophy.

Moreover, the researchers have learned that Gadd45a does its work inside the muscle cell’s nucleus, causing deterioration as it reprograms hundreds of genes, according to the press release.

“We now understand a key molecular mechanism of skeletal muscle atrophy,” says Christopher Adams, associate professor of internal medicine at the UI and corresponding author on the paper published in the Journal of Biological Chemistry. “This finding could help us find a therapy for treating muscle atrophy in patients, and we now know a great place to start is by reducing Gadd45a.”

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