hsp70-DnaJ chaperone pair prevents nitric oxide- and CHOP-induced apoptosis by inhibiting translocation of Bax to mitochondria

Cell Death Differ. 2004 Apr;11(4):390-402. doi: 10.1038/sj.cdd.4401369.


We reported that the endoplasmic reticulum (ER) stress pathway involving CHOP, a member of the C/EBP transcription factor family, plays a key role in nitric oxide (NO)-mediated apoptosis of macrophages and pancreatic beta cells. We also showed that the cytosolic chaperone pair of hsp70 and dj1 (hsp40/hdj-1) or dj2 (HSDJ/hdj-2) prevents NO-mediated apoptosis upstream of cytochrome c release from mitochondria. To analyze roles of the chaperone pair in preventing apoptosis, RAW 264.7 macrophages stably expressing hsp70 and dj1 or dj2 were established. The chaperone pair prevented LPS/IFN-gamma-induced and NO-mediated apoptosis downstream of CHOP induction. hsp70 mutant protein lacking the ATPase domain or the C-terminal EEVD sequence were not effective in preventing CHOP-induced apoptosis. A mutant dj2 lacking the C-terminal prenylation CaaX motif, was also not effective. When wild-type RAW 264.7 cells were treated with LPS/IFN-gamma, NO-mediated apoptosis was induced, and proapoptotic Bcl-2 family protein Bax was translocated from cytosol to mitochondria. This translocation was prevented in cells stably expressing hsp70/dj2, and in CHOP knockout cells. Overexpression of CHOP in wild-type cells also induced translocation of Bax and this translocation was prevented in cells expressing hsp70/dj2. CHOP-induced apoptosis was prevented by Bax knock-down. Coimmunoprecipitation experiments showed that Bax interacts with both hsp70 and dj1/dj2. ATPase domain of hsp70 was necessary for the binding with Bax. These findings indicate that CHOP-induced apoptosis is mediated by translocation of Bax from the cytosol to the mitochondria, and hsp70/dj1 or dj2 chaperone pair prevents apoptosis by interacting with Bax and preventing translocation to the mitochondria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / metabolism
  • Animals
  • Apoptosis / physiology
  • CCAAT-Enhancer-Binding Proteins / antagonists & inhibitors*
  • CCAAT-Enhancer-Binding Proteins / metabolism
  • COS Cells
  • Cell Line
  • Chlorocebus aethiops
  • Cytosol / metabolism
  • HSP40 Heat-Shock Proteins
  • HSP70 Heat-Shock Proteins / genetics
  • HSP70 Heat-Shock Proteins / physiology*
  • Heat-Shock Proteins / genetics
  • Heat-Shock Proteins / physiology*
  • Macrophages / cytology
  • Macrophages / metabolism
  • Mice
  • Mice, Knockout
  • Mitochondria / metabolism
  • Molecular Chaperones / metabolism
  • Molecular Chaperones / pharmacology*
  • Nitric Oxide / antagonists & inhibitors*
  • Protein Transport / physiology
  • Proto-Oncogene Proteins / antagonists & inhibitors
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-bcl-2*
  • Transcription Factor CHOP
  • Transcription Factors / antagonists & inhibitors*
  • Transcription Factors / metabolism
  • Transfection
  • bcl-2-Associated X Protein


  • Bax protein, mouse
  • CCAAT-Enhancer-Binding Proteins
  • Ddit3 protein, mouse
  • Dnaja1 protein, mouse
  • HSP40 Heat-Shock Proteins
  • HSP70 Heat-Shock Proteins
  • Heat-Shock Proteins
  • Molecular Chaperones
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • Transcription Factors
  • bcl-2-Associated X Protein
  • Transcription Factor CHOP
  • Nitric Oxide
  • Adenosine Triphosphatases