A gene for speed: Contractile properties of isolated whole EDL muscle from an α-actinin-3 knockout mouse

Abstract

The actin-binding protein α-actinin-3 is one of the two isoforms of α-actinin that are found in the Z-discs of skeletal muscle. α-Actinin-3 is exclusively expressed in fast glycolytic muscle fibers. Homozygosity for a common polymorphism in the ACTN3 gene results in complete deficiency of α-actinin-3 in about 1 billion individuals worldwide. Recent genetic studies suggest that the absence of α-actinin-3 is detrimental to sprint and power performance in elite athletes and in the general population. In contrast, α-actinin-3 deficiency appears to be beneficial for endurance athletes. To determine the effect of α-actinin-3 deficiency on the contractile properties of skeletal muscle, we studied i..