F-actin-capping proteins bind in a Ca(2+)-independent manner to the fast growing ends of actin filaments (barbed end) thereby blocking the exchange of subunits at these ends. Unlike other capping proteins (such as gelsolin and severin), these proteins do not sever actin filaments. This is the function of CAPZA2 (capping actin protein of muscle Z-line subunit alpha 2, ENSG00000198898).