| Here we demonstrate a novel p 53 independent interaction between the nucleolar tumor suppressors , p 14 Arf and Werners helicase ( WRN ) . ^^^ Binding of p 14 Arf to WRN is multivalent and resembles the binding of p 14 Arf to Mdm 2 . ^^^ Residues 2 14 and 82 101 of p 14 Arf and residues in the central region and C terminus of WRN have particular importance for binding . p 14 Arf promotes small ubiquitin like modifier ( SUMO ) modification of WRN in a synergistic manner with the SUMO conjugating enzyme , UBCH 9 . p 14 Arf causes redistribution of WRN within the nucleus , and this effect is reversed by expression of a SUMO specific protease , thus implicating the SUMO conjugation pathway in WRN re localization . ^^^ |