title: Phosphorylation of protein inhibitor of activated STAT1 (PIAS1) by MAPK-activated protein kinase-2 inhibits endothelial inflammation via increasing both PIAS1 transrepression and SUMO E3 ligase activity.
abstract: OBJECTIVE
  Protein inhibitor of activated signal transducer and activator of transcription-1 (PIAS1) is known to function as small ubiquitin-like modifier (SUMO) E3 ligase as well as transrepressor. The aim of the study is to elucidate the regulatory mechanisms for these 2 different functions, especially with respect to endothelial inflammation.
  
  
  RESULTS
  The mitogen-activated protein kinase (MAPK)-activated protein kinase-2 is a proinflammatory kinase and phosphorylates PIAS1 at the Ser522 residue. Activation of MAPK-activated protein kinase-2 enhances p53-SUMOylation, but a PIAS1 phosphorylation mutant, PIAS1-S522A, abolished this p53-SUMOylation, suggesting a critical role for PIAS1-S522 phosphorylation in its SUMO ligase activity. Because nuclear p53 can inhibit Kruppel-like factor 2 promoter activity, we investigated the roles for PIAS1 phosphorylation and p53-SUMOylation in the Kruppel-like factor 2 and endothelial NO synthase expression. Both MAPK-activated protein kinase-2 and PIAS1 overexpression increased Kruppel-like factor 2 promoter activity and endothelial NO synthase expression, which were inhibited by expressing a p53-SUMOylation defective mutant, p53-K386R, and PIAS1-S522A. PIAS1-S522A also abolished the anti-inflammatory effect of wild-type PIAS1 in vitro and also in vivo, which was examined by leukocyte rolling in microvessels of skin grafts transduced by adenovirus encoding PIAS1-WT or - S522A mutant.
  
  
  CONCLUSIONS
  Our study has identified a novel negative feedback regulatory pathway through which MAPK-activated protein kinase-2 limits endothelial inflammation via the PIAS1 S522 phosphorylation-mediated increase in PIAS1 transrepression and SUMO ligase activity.
authors.affiliation: Aab Cardiovascular Research Institute and Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
authors.forename: Kyung-Sun
authors.initials: KS
authors.lastname: Heo
authors.forename: Eugene
authors.initials: E
authors.lastname: Chang
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Takei
authors.forename: Nhat-Tu
authors.initials: NT
authors.lastname: Le
authors.forename: Chang-Hoon
authors.initials: CH
authors.lastname: Woo
authors.forename: Mark A
authors.initials: MA
authors.lastname: Sullivan
authors.forename: Craig
authors.initials: C
authors.lastname: Morrell
authors.forename: Keigi
authors.initials: K
authors.lastname: Fujiwara
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Abe
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology* / Q000276:immunology; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D061307:Human Umbilical Vein Endothelial Cells / Q000201:enzymology / Q000276:immunology; D006801:Humans; D007249:Inflammation / Q000201:enzymology / Q000276:immunology / Q000517:prevention & control*; D018836:Inflammation Mediators / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D051741:Kruppel-Like Transcription Factors / Q000378:metabolism; D036904:Leukocyte Rolling; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010766:Phosphorylation; D050828:Protein Inhibitors of Activated STAT / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D012867:Skin / Q000098:blood supply; D016038:Skin Transplantation; D025841:Small Ubiquitin-Related Modifier Proteins / Q000235:genetics / Q000378:metabolism*; D058207:Sumoylation; D013997:Time Factors; D014162:Transfection; D014182:Transplantation, Autologous; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D000099190:MAP-Kinase-Activated Kinase 2
chemical_list: D018836:Inflammation Mediators; D047908:Intracellular Signaling Peptides and Proteins; D051741:Kruppel-Like Transcription Factors; D016328:NF-kappa B; D052250:Nitric Oxide Synthase Type III; D050828:Protein Inhibitors of Activated STAT; D017346:Protein Serine-Threonine Kinases; D025841:Small Ubiquitin-Related Modifier Proteins; D014409:Tumor Necrosis Factor-alpha; D016159:Tumor Suppressor Protein p53; D044767:Ubiquitin-Protein Ligases; D000099190:MAP-Kinase-Activated Kinase 2; C096161:KLF2 protein, human; C106529:PIAS1 protein, human; C494211:Pias1 protein, mouse; C495901:TP53 protein, human; C496314:NOS3 protein, human