Coiled Coil Domain Containing Protein 80 (CCDC80)

The Urb protein contains a highly hydrophobic N-terminal signal sequence, indicating that it is a secretory protein, 3 N-glycosylation sites, several pairs of basic amino acids, and a lysine-rich region containing nuclear localization signals. Three consensus repeat domains in Urb share about 30% amino acid identity with the fifth domain of the human SRPX protein, suggesting that Urb may be functionally related to the sushi protein superfamily. The nucleotide sequences of Urb and rat Ssg1 share more than 90% identity, but several mismatches result in a frameshift, and the Ssg1 protein contains only 385 residues. In situ hybridization of mouse brain showed expression of Urb in the anterior olfactory nucleus, dorsal endopiriform nucleus, and choroid plexus; weak expression was observed in the cortex.