Anti-RNF121 antibodies are used in the immunodetection of the protein ring finger protein 121. In humans, the canonical protein has a reported length of 327 amino acid residues and a mass of 37.9 kDa. Its subcellular localization is in the ER. Alternative splicing is reported to yield 2 different isoforms for this protein. A member of the RNF121 protein family, it is known to be involved with protein ubiquitination. Synonyms for this target antigen include E3 ubiquitin ligase RNF121.