Anti-SPAG5 antibodies are used in the immunodetection of the protein sperm associated antigen 5. In humans, the canonical protein has a reported length of 1193 amino acid residues and a mass of 134.4 kDa. Its subcellular localization is in the cytoplasm. It is reported to be highly expressed in testis. SPAG5 is an important component of the mitotic spindle required for normal chromosome segregation and progression into anaphase. Post-translational modifications have been described, including phosphorylation. Synonyms for this target antigen include MAP126, hMAP126, astrin, mitotic spindle associated protein p126, mitotic spindle coiled-coil related protein, and DEEPEST.