Actin finally matures: uncovering machinery and impact.

Actin, one of the most abundant proteins in nature and a key component of the cytoskeleton, undergoes a unique multistep N-terminal (Nt) maturation. In a recent report, Haahr et al. identified actin maturation protease (ACTMAP) as the dedicated actin aminopeptidase and showed that its absence is associated with abnormal muscle physiology.