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.
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.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.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.
Mesh Terms:
Animals, Cells, Cultured, Endothelial Cells, Enzyme Activation, Gene Expression Regulation, Human Umbilical Vein Endothelial Cells, Humans, Inflammation, Inflammation Mediators, Intracellular Signaling Peptides and Proteins, Kruppel-Like Transcription Factors, Leukocyte Rolling, Mice, Mice, Inbred C57BL, NF-kappa B, Nitric Oxide Synthase Type III, Phosphorylation, Protein Inhibitors of Activated STAT, Protein-Serine-Threonine Kinases, RNA Interference, Skin, Skin Transplantation, Small Ubiquitin-Related Modifier Proteins, Sumoylation, Time Factors, Transfection, Transplantation, Autologous, Tumor Necrosis Factor-alpha, Tumor Suppressor Protein p53, Ubiquitin-Protein Ligases
Animals, Cells, Cultured, Endothelial Cells, Enzyme Activation, Gene Expression Regulation, Human Umbilical Vein Endothelial Cells, Humans, Inflammation, Inflammation Mediators, Intracellular Signaling Peptides and Proteins, Kruppel-Like Transcription Factors, Leukocyte Rolling, Mice, Mice, Inbred C57BL, NF-kappa B, Nitric Oxide Synthase Type III, Phosphorylation, Protein Inhibitors of Activated STAT, Protein-Serine-Threonine Kinases, RNA Interference, Skin, Skin Transplantation, Small Ubiquitin-Related Modifier Proteins, Sumoylation, Time Factors, Transfection, Transplantation, Autologous, Tumor Necrosis Factor-alpha, Tumor Suppressor Protein p53, Ubiquitin-Protein Ligases
Arterioscler. Thromb. Vasc. Biol.
Date: Feb. 01, 2013
PubMed ID: 23202365
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