Heat shock factor 2 is involved in the upregulation of alphaB-crystallin by high extracellular potassium

J Biochem. 2001 May;129(5):813-20. doi: 10.1093/oxfordjournals.jbchem.a002924.

Abstract

alphaB-Crystallin, a member of the small heat shock protein (HSP) family, accumulates in reactive astrocytes in a variety of pathological conditions. We previously reported the upregulation of alphaB-crystallin in response to high extracellular potassium concentration. In the present study, we investigated the regulatory mechanism of alphaB-crystallin expression by KCl. When human glioma U-251MG cells were exposed to continuous KCl treatment, induction of alphaB-crystallin mRNA was observed after 8 h and persisted for a few days. Functional promoter analysis using deletion and mutation constructs revealed that the proximal heat shock element (HSE-P), which contributes to heat shock induction in HeLa cells, is essential for transcriptional activation of the alphaB-crystallin gene by KCl in U-251MG cells. Gel mobility shift and antibody supershift assays showed that KCl induces the HSE-binding activity of heat shock factor (HSF) 2, while heat shock induces that of HSF1. This is the first demonstration that HSF2 can be activated by KCl and is involved in the upregulation of alphaB-crystallin gene expression in glial cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites / drug effects
  • Crystallins / agonists*
  • Crystallins / biosynthesis
  • Crystallins / genetics*
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / drug effects
  • DNA-Binding Proteins / metabolism*
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / genetics
  • Glioma / metabolism
  • HeLa Cells / metabolism
  • Heat Shock Transcription Factors
  • Heat Stress Disorders / metabolism*
  • Heat-Shock Proteins / chemistry
  • Heat-Shock Proteins / drug effects
  • Heat-Shock Proteins / metabolism*
  • Humans
  • Potassium Chloride / metabolism
  • Potassium Chloride / pharmacology*
  • Promoter Regions, Genetic / drug effects
  • Promoter Regions, Genetic / genetics
  • RNA, Messenger / agonists
  • RNA, Messenger / genetics
  • Transcription Factors / chemistry
  • Transcription Factors / drug effects
  • Transcription Factors / metabolism*
  • Transcriptional Activation / drug effects
  • Transcriptional Activation / genetics
  • Tumor Cells, Cultured / metabolism
  • Up-Regulation

Substances

  • Crystallins
  • DNA-Binding Proteins
  • HSF1 protein, human
  • Heat Shock Transcription Factors
  • Heat-Shock Proteins
  • RNA, Messenger
  • Transcription Factors
  • HSF2 protein, human
  • Potassium Chloride