Anti-actin like 9 antibodies are used in the immunodetection of the protein encoded by the ACTL9 gene. In humans, the canonical protein has a reported length of 416 amino acid residues and a mass of 45.5 kDa. Its subcellular localization is in the cytoplasmic vesicles and cytoplasm. It is reported to have testis-specific expression. A member of the Actin protein family, it is reported to be a testis-specic protein that plays an important role in fusion of proacrosomal vesicles and perinuclear theca formation. Other names for this target antigen include testicular tissue protein Li 15, testicular tissue protein Li 9, and actin-like protein 9.