Mice surpass human runners in their endurance on an exercise wheel, covering distances of 10 kilometers or more per night. However, a group of mice genetically altered to lack a muscle protein demonstrated even greater muscle performance. These mice were able to scurry up a steep 10% grade on a treadmill for approximately 90 minutes before tiring, which was 31% longer than other mice. This small genetic alteration resulted in enhanced muscle performance, as if the “brakes” were taken off, according to muscle biologist Eric Olson of the University of Texas Southwestern Medical Center in Dallas.
What surprised researchers was the discovery of the crucial protein that was disabled. Unlike the massive proteins found in muscles, this protein, called myoregulin, only consisted of 46 amino acids. Despite this, it had a significant impact on muscle function, which had been previously overlooked. Scientists are now realizing that their initial rules for analyzing genomes prevented them from identifying these smaller proteins. However, with broader criteria and improved detection methods, researchers are beginning to uncover thousands of minuscule proteins, not just in mice, but in various other species, including humans. This new discovery is allowing scientists to explore the functions of these microproteins, which seem to have the ability to inhibit and unleash different cellular processes. Early findings suggest that microproteins play a role in immune system function, RNA molecule destruction, protection against extreme temperatures, flowering in plants, and the production of venom. Researchers believe that small proteins are involved in all biological processes but have not been previously identified.