Enhances the sumoylation of a number of proteins including HIF1A, PIAS and I-kappa-B, through direct interaction with UBC9. Has no effect on ubiquitination.
Expressed in a wide number of tissues with highest expression in cerebellum, pituitary, heart, kidney, liver, stomach, pancreas, prostate and spleen. Low levels in thalamus, spinal cord, esophagus, thymus, lung and peripheral blood leukocytes.
Contains 1 RWD domain.
The RWD domain is required for the sumoylation enhancement activity.
Nucleus. Cytoplasm. Colocalizes with UBC9/UBE2I in nuclear spots.