Sgt1 has co-chaperone properties and is up-regulated by heat shock.
The Sgt1 protein is a binding partner of heat shock proteins such as Hsp90, Hsp70 or Hsc70. In this work we show that the level of Sgt1 is increased in HEp-2 cells exposed to heat shock or radicicol. The citrate synthase aggregation assay shows that Sgt1 attenuates aggregation of the enzyme induced by increased temperature as efficiently as p23, a known co-chaperone of Hsp90. We have cloned two fragments of the human Sgt1 gene promoter (-708/+98 and -351/+98) into pGL3-luciferase vector and found that both fragments generated a 2-fold increase in luciferase activity upon heat shock. Furthermore, electrophoretic mobility shift assay revealed binding of the HSF-1 transcription factor to the heat shock element in the proximal (-42/-2) Sgt1 gene promoter fragment. These results indicate that Sgt1 is a co-chaperone protein with an expression pattern matching that of the well known heat shock proteins.
Zabka
Magdalena
M
Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093 Warsaw, Poland.
Leśniak
Wiesława
W
Prus
Wiktor
W
Kuźnicki
Jacek
J
Filipek
Anna
A
D000818:Animals; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002478:Cells, Cultured; D002950:Citrate (si)-Synthase / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D000076249:Heat Shock Transcription Factors; D018869:Heat-Shock Response; D006801:Humans; D008156:Luciferases / Q000235:genetics; D018942:Macrolides / Q000494:pharmacology; D018832:Molecular Chaperones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D014157:Transcription Factors / Q000378:metabolism; D015854:Up-Regulation
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D000076249:Heat Shock Transcription Factors; D018942:Macrolides; D018832:Molecular Chaperones; D047428:Protein Kinase Inhibitors; C490164:SUGT1 protein, human; D014157:Transcription Factors; D008156:Luciferases; D002950:Citrate (si)-Synthase; C035359:monorden