title: UBC9 autosumoylation negatively regulates sumoylation of septins in Saccharomyces cerevisiae.
abstract: Sumoylation regulates a wide range of cellular processes. However, little is known about the regulation of the SUMO machinery. In this study, we demonstrate that two lysine residues (Lys-153 and Lys-157) in the C-terminal region of the yeast E2-conjugating enzyme Ubc9 are the major and minor autosumoylation sites, respectively. Surprisingly, mutation of Lys-157 (ubc9(K157R)) significantly stimulates the level of Ubc9 autosumoylation at Lys-153. The functional role of Ubc9 autosumoylation is exemplified in our findings that cell cycle-dependent sumoylation of cytoskeletal septin proteins is inversely correlated with the Ubc9 autosumoylation level and that mutation of the Ubc9 autosumoylation sites results in aberrant cell morphology. Our study elucidates a regulatory mechanism that utilizes automodification of the E2 enzyme of the sumoylation machinery to control substrate sumoylation.
authors.affiliation: Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan.
authors.forename: Chia-Wen
authors.initials: CW
authors.lastname: Ho
authors.forename: Hung-Ta
authors.initials: HT
authors.lastname: Chen
authors.forename: Jaulang
authors.initials: J
authors.lastname: Hwang
mesh_terms: D000595:Amino Acid Sequence; D003599:Cytoskeleton / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D008239:Lysine / Q000737:chemistry; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D058112:Septins / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D058207:Sumoylation; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism*; D000098843:Ubiquitin-Conjugating Enzyme UBC9
chemical_list: D011994:Recombinant Proteins; D044763:Ubiquitin-Conjugating Enzymes; D058112:Septins; D000098843:Ubiquitin-Conjugating Enzyme UBC9; D008239:Lysine