title: Enhanced SUMOylation of proteins containing a SUMO-interacting motif by SUMO-Ubc9 fusion.
abstract: Identifying new targets for SUMO and understanding the function of protein SUMOylation are largely limited by low level of SUMOylation. It was found recently that Ubc9, the SUMO E2 conjugating enzyme, is covalently modified by SUMO at a lysine 14 in the N-terminal alpha helix, and that SUMO-modified Ubc9 has enhanced conjugation activity for certain target proteins containing a SUMO-interacting motif (SIM). Here, we show that, compared to intact Ubc9, the SUMO-Ubc9 fusion protein has higher conjugating activity for SIM-containing targets such as Sp100 and human cytomegalovirus IE2. Assays using an IE2 SIM mutant revealed the requirement of SIM for the enhanced IE2 SUMOylation by SUMO-Ubc9. In pull-down assays with cell extracts, the SUMO-Ubc9 fusion protein bound to more diverse cellular proteins and interacted with some SIM-containing proteins with higher affinities than Ubc9. Therefore, the devised SUMO-Ubc9 fusion will be useful for identifying SIM-containing SUMO targets and producing SUMO-modified proteins.
authors.affiliation: Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Cheoncheondong Jangangu, Suwon, Gyeonggido, Republic of Korea.
authors.forename: Eui Tae
authors.initials: ET
authors.lastname: Kim
authors.forename: Kyeong Kyu
authors.initials: KK
authors.lastname: Kim
authors.forename: Mike J
authors.initials: MJ
authors.lastname: Matunis
authors.forename: Jin-Hyun
authors.initials: JH
authors.lastname: Ahn
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D034961:Antigens, Nuclear / Q000378:metabolism; D001324:Autoantigens / Q000378:metabolism; D003587:Cytomegalovirus / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism*; D025841:Small Ubiquitin-Related Modifier Proteins / Q000235:genetics / Q000378:metabolism*; D044763:Ubiquitin-Conjugating Enzymes / Q000235:genetics / Q000378:metabolism*; D000098843:Ubiquitin-Conjugating Enzyme UBC9
chemical_list: D034961:Antigens, Nuclear; D001324:Autoantigens; D011993:Recombinant Fusion Proteins; D025841:Small Ubiquitin-Related Modifier Proteins; C066642:SP100 protein, human; D044763:Ubiquitin-Conjugating Enzymes; D000098843:Ubiquitin-Conjugating Enzyme UBC9