Anti-small RNA binding exonuclease protection factor La antibodies are used for the immunodetection of the protein encoded by the SSB gene. In humans, the canonical protein has a reported length of 408 amino acid residues and a mass of 46.8 kDa. Its subcellular localization is in the nucleus. It is known to bind to the 3' poly(U) terminus of nascent RNA polymerase III transcripts, protecting them from exonuclease digestion and facilitating their folding and maturation. Post-translational modifications have been described, including phosphorylation. Other names for this target antigen include La, La/SSB, lupus La protein, La ribonucleoprotein domain family, member 3, SS-B/La protein, and LARP3. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.