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.
Vietor
I
I
Department of Microbiology, New York University Medical Center, NY 10016.
Vilcek
J
J
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