Subunit of the Slx5-Slx8 SUMO-targeted Ub ligase (STUbL) complex%3B role in Ub-mediated degradation of histone variant Cse4p preventing mislocalization to euchromatin%3B role in proteolysis of spindle positioning protein Kar9p%2C and DNA repair proteins Rad52p and Rad57p%3B forms SUMO-dependent nuclear foci%2C including DNA repair centers%3B contains a RING domain and two SIM motifs%3B associates with the centromere%3B required for maintenance of genome integrity like human ortholog RNF4