The RING-type zinc finger motif is present in a number of viral and eukaryotic proteins and is made of a conserved cysteine-rich domain that is able to bind two zinc atoms. Proteins that contain this conserved domain are generally involved in the ubiquitination pathway of protein degradation. RNF13 (ring finger protein 13), also known as RZF, FLJ93817 or MGC13689, is a novel 381 amino acid E3 ubiquitin ligase that localizes to the nucleus. RNF13 contains one RING-type zinc finger and the C-terminal portion of RNF13 has the ability to mediate ubiquitination. Recent studies suggest that RNF13 may be involved in the development of pancreatic cancer via ubiquitin-mediated modification of proteins. The gene encoding RNF13 maps to human chromsome 3q25.1, and a pseudogene (which is also located on chromosome 3), exists for this gene.