AUP1 contains a domain with homology to the ancient conserved region of the archain 1 gene and a domain thay may be involved in binding ubiquitin-conjugating enzymes. The unprocessed precusor is of 476 amino acids in length and has an estimated molecular weight of 53 kDa. ALTERNATIVE PRODUCTS: 2 named isoforms produced by alternative splicing.TISSUE SPECIFICITY: Ubiquitous. SIMILARITY: Belongs to the AUP1 family. SIMILARITY: Contains 1 CUE domain.