CUE domain-containing protein 2 commonly known as CUEDC2 is a 32 kDa protein having CUE Domain. It is involved in ubiquitin and proteasome-mediated degradation of progesterone receptor and estrogen receptor. It interacts with PRB isoform of progesterone receptor (PR) and modulates estrogen receptor (ER)-alpha protein stability through the ubiquitin-proteasome pathway. High level expression of CUEDC2 found in breast cancer tissue compared to normal adjacent tissue. It is found that CUEDC2 has some role in regulating IKK dephosphorylation by recruiting PP1.