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.
METHODS AND 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.
Original language | English (US) |
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Pages (from-to) | 321-9 |
Number of pages | 9 |
Journal | Arteriosclerosis, Thrombosis, and Vascular Biology |
Volume | 33 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2013 |
Externally published | Yes |
Keywords
- 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
- Journal Article
- Research Support, N.I.H., Extramural
- Research Support, Non-U.S. Gov't
- Video-Audio Media