Pathways of heat shock protein 28 phosphorylation by TNF in human fibroblasts.
Treatment of human diploid FS-4 fibroblasts with TNF or IL-1 led to a rapid increase in the phosphorylation of a approximately 28-kDa protein. Increased phosphorylation was seen after 5 min of TNF treatment, it reached a plateau between 10 and 30 min, and decreased thereafter. Immunoprecipitation with specific antibodies identified the 28-kDa protein as a member of the family of small heat shock proteins (Hsp28). Treatment of cells with different kinase inhibitors (staurosporine, H7, H8, HA-1004, or chelerythrine chloride) failed to inhibit TNF-induced Hsp28 phosphorylation, suggesting that neither protein kinase C nor other common protein kinases were involved. Treatment of FS-4 cells with sodium arsenite led to a very strong increase in the phosphorylation of Hsp28 demonstrable after 5 min and persisting for at least 4 h. Tyrosine phosphorylation of pp42 and pp44 MAP kinases was increased by TNF treatment, whereas arsenite produced a modest increase in tyrosine phosphorylation of pp44 while decreasing that of pp42 MAP kinase. The finding that sodium arsenite strongly increased Hsp28 phosphorylation, together with the resistance of TNF-induced phosphorylation to kinase inhibitors, supports the notion that increased serine phosphorylation of Hsp28 in this system involves inhibition of protein phosphatase activity.
Department of Microbiology, New York University Medical Center, NY 10016.
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Vietor
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Vilcek
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000470:Alkaloids / Q000494:pharmacology; D018053:Arsenites / Q000494:pharmacology; D053119:Benzophenanthridines; D002460:Cell Line; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D010617:Phenanthridines / Q000494:pharmacology; D010766:Phosphorylation; D010770:Phosphotransferases / Q000037:antagonists & inhibitors / Q000378:metabolism; D010879:Piperazines / Q000494:pharmacology; D017670:Sodium Compounds / Q000494:pharmacology; D019311:Staurosporine; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014443:Tyrosine / Q000378:metabolism
D000470:Alkaloids; D018053:Arsenites; D053119:Benzophenanthridines; D006360:Heat-Shock Proteins; D007375:Interleukin-1; D007546:Isoquinolines; D010617:Phenanthridines; D010879:Piperazines; D017670:Sodium Compounds; D014409:Tumor Necrosis Factor-alpha; D014443:Tyrosine; C017947:sodium arsenite; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; C016299:chelerythrine; D010770:Phosphotransferases; D019311:Staurosporine