HDJC9, a novel human type C DnaJ/HSP40 member interacts with and cochaperones HSP70 through the J domain

Biochem Biophys Res Commun. 2007 Feb 9;353(2):280-5. doi: 10.1016/j.bbrc.2006.12.013. Epub 2006 Dec 12.


HSP40s are a subfamily of heat shock proteins (HSPs) and play important roles in regulation of cell proliferation, survival and apoptosis by serving as chaperones for HSP70s. Up to date hundreds of HSP40 proteins derived from various species ranging from Escherichia coli to homo sapiens have been identified. Here we report the cloning and characterization of a novel human type C DnaJ homologue, HDJC9, containing a typical N-terminal J domain. HDJC9 is upregulated at both mRNA and protein levels upon various stress and mitogenic stimulations. HDJC9 is mainly localized in cell nuclei under normal culture conditions while it is transported into cytoplasm and plasma membrane upon heat shock stress through a non-classical and lipid-dependent pathway. HDJC9 can interact with HSP70s and activate the ATPase activity of HSP70s, both of which are dependent on the J domain. Our data suggest that HDJC9 is a novel cochaperone for HSP70s.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • HSP40 Heat-Shock Proteins / metabolism*
  • HSP70 Heat-Shock Proteins / metabolism*
  • Humans
  • Lung Neoplasms / metabolism*
  • Molecular Chaperones / metabolism
  • Protein Interaction Mapping
  • Protein Structure, Tertiary


  • DNAJC9 protein, human
  • HSP40 Heat-Shock Proteins
  • HSP70 Heat-Shock Proteins
  • Molecular Chaperones