Differential regulation of Actn2 and Actn3 expression during unfolded protein response in C2C12 myotubes.

ACTN2 and ACTN3 encode sarcomeric α-actinin-2 and α-actinin-3 proteins, respectively, that constitute the Z-line in mammalian skeletal muscle fibers. In human ACTN3, a nonsense mutation at codon 577 that encodes arginine (R) produces the R577X polymorphism. Individuals having a homozygous 577XX genotype do not produce α-actinin-3 protein.