This domain family is found in eukaryotes, and is approximately 60 amino acids in length. The family is found in association with pfam00638, pfam00641, pfam00160. There are two conserved sequence motifs: TFFC and EDF. Nup358/RanBP2 is a nucleoporin involved in ubiquitination of many different protein targets from various cellular pathways. It complexes with Ubc9, SUMO-1 and RanGAP1 to perform this function. This is the ligase domain which binds to Ubc9.