CUE domain found in fungal RNA polymerase II degradation factor 1 (DEF1) and similar proteins
DEF1, also called RRM3-interacting protein 1, is a RNA Polymerase II (RNAPII) degradation factor that may be required to couple arrested RNAPII to the proteasome to facilitate its degradation. It contains a CUE domain that is responsible for the binding of ubiquitin. The family also includes many uncharacterized hypothetical proteins. They show a high level of sequence similarity with DEF1.