Heat shock-mediated regulation of MKP-1.
Heat shock modulates cellular proinflammatory responses, and we have been interested in elucidating the mechanisms that govern this modulation. The dual specific phosphatase, MAP kinase phosphatase-1 (MKP-1), is an important modulator of cellular inflammatory responses, and we recently reported that heat shock increases expression of MKP-1. Herein we sought to elucidate the mechanisms by which heat shock modulates MKP-1 gene expression. Subjecting RAW264.7 macrophages to heat shock increased MKP-1 gene expression in a time-dependent manner. Transfection with a wild-type murine MKP-1 promoter luciferase reporter plasmid demonstrated that heat shock activates the MKP-1 promoter. When the reporter plasmid was transfected into heat shock factor-1 (HSF-1)-null fibroblasts, the MKP-1 promoter was activated in response to heat shock in a manner similar to that of wild-type fibroblasts with intact HSF-1. Site-directed mutagenesis of two potential heat shock elements in the MKP-1 promoter demonstrated that both sites are required for basal promoter activity. mRNA stability assays demonstrated that heat shock increased MKP-1 mRNA stability compared with cells maintained at 37 degrees C. Inhibition of p38 MAP kinase activity inhibited heat shock-mediated expression of MKP-1. These data demonstrate that heat shock regulates MKP-1 gene expression at both the transcriptional and posttranscriptional levels. Transcriptional mechanisms are HSF-1 independent but are dependent on putative heat shock elements in the MKP-1 promoter. Posttranscriptional mechanisms involve increased stability of MKP-1 mRNA that is partially dependent on p38 MAP kinase activity. These data demonstrate another potential mechanism by which heat shock can modulate inflammation-related signal transduction.
Wong
Hector R
HR
Division of Critical Care Medicine, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, USA. wonghr@cchmc.org
Dunsmore
Katherine E
KE
Page
Kristen
K
Shanley
Thomas P
TP
D000818:Animals; D018797:Cell Cycle Proteins / Q000096:biosynthesis*; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D003609:Dactinomycin / Q000494:pharmacology; D054638:Dual Specificity Phosphatase 1; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000378:metabolism; D006358:Hot Temperature; D017874:Immediate-Early Proteins / Q000096:biosynthesis*; D008264:Macrophages / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D010749:Phosphoprotein Phosphatases / Q000096:biosynthesis*; D011401:Promoter Regions, Genetic / Q000502:physiology; D054645:Protein Phosphatase 1; D017027:Protein Tyrosine Phosphatases / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; C490017:Hsf1 protein, mouse; D017874:Immediate-Early Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D003609:Dactinomycin; D048051:p38 Mitogen-Activated Protein Kinases; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D054638:Dual Specificity Phosphatase 1; C517020:Dusp1 protein, mouse; D017027:Protein Tyrosine Phosphatases