Fiber-type specific expression of α-actinin isoforms in rat skeletal muscle

► We investigated the expression of α-actinin isoforms in rat skeletal muscle. ► α-Actinin-3 is expressed in all type IIx+b fibers but not in type I fibers. ► Proportions of α-actinin-3 in type IIa fibers are higher in the soleus. ► α-Actinin-2 is expressed in all fibers regardless of the fiber type. ► α-Actinin expression in rat is considered closer to that of humans than mice.