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 (By similarity). Heterodimer of an alpha and a beta subunit. Component of the WASH complex, composed of F-actin-capping protein subunit alpha (CAPZA1, CAPZA2 or CAPZA3), F-actin-capping protein subunit beta (CAPZB), WASHC1, WASHC2, WASHC3, WASHC4 and WASHC5. Interacts with RCSD1/CAPZIP (By similarity). Directly interacts with CRACD; this interaction decreases binding to actin (By similarity). Belongs to the F-actin-capping protein alpha subunit family.