title: SUMO1 negatively regulates reactive oxygen species production from NADPH oxidases.
abstract: OBJECTIVE
  Increased protein SUMOylation (small ubiquitin-related modifier [SUMO]) provides protection from cellular stress, including oxidative stress, but the mechanisms involved are incompletely understood. The NADPH oxidases (Nox) are a primary source of reactive oxygen species (ROS) and oxidative stress, and thus our goal was to determine whether SUMO regulates NADPH oxidase activity.
  
  
  RESULTS
  Increased expression of SUMO1 potently inhibited the activity of Nox1 to Nox5. In contrast, inhibition of endogenous SUMOylation with small interfering RNA to SUMO1 or ubiquitin conjugating enzyme 9 or with the inhibitor anacardic acid increased ROS production from human embryonic kidney-Nox5 cells, human vascular smooth muscle cells, and neutrophils. The suppression of ROS production was unique to SUMO1, and it required a C-terminal diglycine and the SUMO-specific conjugating enzyme ubiquitin conjugating enzyme 9. SUMO1 did not modify intracellular calcium or Nox5 phosphorylation but reduced ROS output in an isolated enzyme assay, suggesting direct effects of SUMOylation on enzyme activity. However, we could not detect the presence of SUMO1 conjugation on Nox5 using a variety of approaches. Moreover, the mutation of more than 17 predicted and conserved lysine residues on Nox5 did not alter the inhibitory actions of SUMO1.
  
  
  CONCLUSIONS
  Together, these results suggest that SUMO is an important regulatory mechanism that indirectly represses the production of ROS to ameliorate cellular stress.
authors.affiliation: Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912, USA.
authors.forename: Deepesh
authors.initials: D
authors.lastname: Pandey
authors.forename: Feng
authors.initials: F
authors.lastname: Chen
authors.forename: Anand
authors.initials: A
authors.lastname: Patel
authors.forename: Cong-Yi
authors.initials: CY
authors.lastname: Wang
authors.forename: Christiana
authors.initials: C
authors.lastname: Dimitropoulou
authors.forename: Vijay S
authors.initials: VS
authors.lastname: Patel
authors.forename: R Daniel
authors.initials: RD
authors.lastname: Rudic
authors.forename: David W
authors.initials: DW
authors.lastname: Stepp
authors.forename: David J
authors.initials: DJ
authors.lastname: Fulton
mesh_terms: D048729:Anacardic Acids / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D019556:COS Cells; D002118:Calcium / Q000378:metabolism; D002522:Chlorocebus aethiops; D015536:Down-Regulation; D057809:HEK293 Cells; D006801:Humans; D007527:Isoenzymes; D008239:Lysine; D009131:Muscle, Smooth, Vascular / Q000201:enzymology; D009154:Mutation; D032389:Myocytes, Smooth Muscle / Q000201:enzymology; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D009504:Neutrophils / Q000201:enzymology; D018384:Oxidative Stress / Q000187:drug effects; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D055550:Protein Stability; D034622:RNA Interference; D017382:Reactive Oxygen Species / Q000378:metabolism*; D025842:SUMO-1 Protein / Q000235:genetics / Q000378:metabolism*; D058207:Sumoylation; D013997:Time Factors; D014162:Transfection; D044763:Ubiquitin-Conjugating Enzymes / Q000235:genetics / Q000378:metabolism; D000098843:Ubiquitin-Conjugating Enzyme UBC9
chemical_list: D048729:Anacardic Acids; D007527:Isoenzymes; D017382:Reactive Oxygen Species; D025842:SUMO-1 Protein; C495501:SUMO1 protein, human; C088115:anacardic acid; D019255:NADPH Oxidases; D044763:Ubiquitin-Conjugating Enzymes; D000098843:Ubiquitin-Conjugating Enzyme UBC9; D008239:Lysine; D002118:Calcium