UI study shows what happens to muscles during exercise

A University of Iowa study shows why muscle membranes don't rupture when healthy people exercise.

Findings shed light on a mechanism that appears to protect cells from mechanical stress.

The study, which appears online in Proceedings of the National Academy of Sciences Early Edition, also helps explain why muscle damage is so severe when this mechanism is disrupted, which occurs in certain congenital and limb-girdle muscular dystrophies.

The team identified a protein called alpha dystroglycan as the “glue” that binds muscle membranes to a tough layer of extracellular proteins called the basal lamina.

Just as a piece of sticky tape can prevent a pin from bursting a balloon, the sturdy basal lamina reinforces muscle cell membranes and keeps small tears from bursting open, but only if the dystroglycan “glue” affixing the basal lamina to the membrane is working.

“This study helps us understand how membrane structure is designed to protect cells, which is a universally important process,” said senior study author Kevin Campbell, professor and head of molecular physiology and biophysics at the UI Carver College of Medicine.

The study was funded in part by a National Institutes of Health grant for the Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center at the UI, and by grants from the Muscular Dystrophy Association, the Welcome Trust and the U.S. Department of Defense.