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. CapZ may mediate the attachment of the barbed ends of actin filaments to the Z-line. Heterodimer of an alpha and a beta subunit. Component of the WASH complex (By similarity). CapZ is located at the Z line in chicken muscle. Present in all tissues examined. Belongs to the F-actin-capping protein alpha subunit family.