ACTC1
ACTC1 encodes cardiac muscle alpha actin. This isoform differs from the alpha actin that is expressed in skeletal muscle, ACTA1. Alpha cardiac actin is the major protein of the thin filament in cardiac sarcomeres, which are responsible for muscle contraction and generation of force to support the pump function of the heart.
Cardiac alpha actin is a 42.0 kDa protein composed of 377 amino acids. Cardiac alpha actin is a filamentous protein extending from a complex mesh with cardiac alpha-actinin (ACTN2) at Z-lines towards the center of the sarcomere. Polymerization of globular actin (G-actin) leads to a structural filament (F-actin) in the form of a two-stranded helix. Each actin can bind to four others. The atomic structure of monomeric actin was solved by Kabsch et al., and closely thereafter this same group published the structure of the actin filament.Actins are highly conserved proteins; the alpha actins are found in muscle tissues and are a major constituent of the contractile apparatus. Cardiac (ACTC1) and skeletal (ACTA1) alpha actins differ by only four amino acids (Asp4Glu, Glu5Asp, Leu301Met, Ser360Thr; cardiac/skeletal). The actin monomer has two asymmetric domains; the larger inner domain comprised by sub-domains 3 and 4, and the smaller outer domain by sub-domains 1 and 2. Both the amino and carboxy-termini lie in sub-domain 1 of the outer domain.
...
Wikipedia