Zinc-finger proteins contain DNA-binding domains and have a wide variety of functions, most of which encompass some form of transcriptional activation or repression. 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. ZNRF1 (zinc and ring finger 1), also known as NIN283, is a 227 amino acid protein that contains one RING-type zinc finger and localizes to the lysosome and the endosome, as well as to cytoplasmic vesicles and the peripheral membrane. Expressed primarily in nervous system tissue, but also present in testis and thymus, ZNRF1 functions as an E3 ubiquitin-protein ligase that is thought to play a role in the establishment and maintenance of neuronal plasticity. Multiple isoforms of ZNRF1 exist due to alternative splicing events.