Capping Protein Muscle Z Line Alpha 3 (CAPZa3)

CAPZa3 encodes an actin capping protein, one of the F-actin capping protein alpha subunit family. The encoded protein is predominantly localized to the neck region of ejaculated sperm, other immunohistochemical signals were found in the tail and postacrosomal regions. The encoded protein may also form heterodimers of alpha and beta subunits. This protein may be important in determining sperm architecture and male fertility.The deduced 299-amino acid protein shares 91.3% identity with mouse Capza3. The C-terminal domain of CAPZA3 contains an F-actin capping protein alpha subunit signature-2 sequence and a putative S100 protein-binding site. CAPZA3 also has 2 arg residues essential for capping protein function. Northern blot analysis of several human tissues detected a 1.2-kb transcript only in testis.