title: HDJC9, a novel human type C DnaJ/HSP40 member interacts with and cochaperones HSP70 through the J domain.
abstract: 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.
authors.affiliation: Institute of Immunology, Tsinghua University, Beijing 100084, PR China.
authors.forename: Chaofeng
authors.initials: C
authors.lastname: Han
authors.forename: Taoyong
authors.initials: T
authors.lastname: Chen
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.forename: Mingjin
authors.initials: M
authors.lastname: Yang
authors.forename: Tao
authors.initials: T
authors.lastname: Wan
authors.forename: Xuetao
authors.initials: X
authors.lastname: Cao
mesh_terms: D045744:Cell Line, Tumor; D050956:HSP40 Heat-Shock Proteins / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism*; D018832:Molecular Chaperones / Q000378:metabolism; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary
chemical_list: C494654:DNAJC9 protein, human; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D018832:Molecular Chaperones