is a microfilament
is necessary for the attachment of actin
filaments to the z-line
membrane, in muscle cells. The functional protein is an anti-parallel dimer, which cross-links the thin filaments in adjacent sarcomeres
, and therefore coordinated contractions between sarcomeres in the horizontal axis.
The non-sarcomeric α-actinins (ACTN1 and ACTN4) are widely expressed. Both ends of the rod-shaped α-actinin dimer contain actin-binding domains.
Mutations in ACTN4 can cause the kidney disease focal segmental glomerulosclerosis.