The CUE (coupling of ubiquitin conjugation to endoplasmic reticulum degradation) domain is an evolutionarily conserved, ~40 amino acid monoubiquitin-binding domain that mediates intramolecular monoubiquitylation. CUE domains are present in eukaryotic proteins that are involved in ubiquitination and protein trafficking pathways and may be required for ubiquitination of the proteins in which they are found. CUEDC1 (CUE domain-containing protein 1) is a 386 amino acid protein that contains one CUE domain, suggesting a possible role in protein trafficking and degradation pathways. Two isoforms of CUEDC1 exist due to alternative splicing events. Defects in the gene encoding CUEDC1 may be associated with early stage cervical cancer, implicating CUEDC1 as a potential tumor marker.
CUE domain-containing protein 1