A stress-inducible 40 kDa protein (hsp40): Purification by modified two-dimensional gel electrophoresis and co-localization with hsc70(p73) in heat-shocked HeLa cells

Hirotomo Hattori, Toshio Kaneda, Balakrishna Lokeshwar, Andrei Laszlo, Kenzo Ohtsuka

Research output: Contribution to journalArticle

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We have previously reported that a novel 40 RDa protein is induced by heat shock and several environmental stresses in mammalian and avian cells and that the N-terminal amino acid sequence of this 40 kDa protein has homology with the bacterial DnaJ heat-shock protein. We have purified this protein (40 kDa heat-shock protein, hsp40) from HeLa cells by modified two-dimensional gel electrophoresis and generated a polyclonal antibody against hsp40. This antibody was highly specific for human hsp40 and cross-reacted weakly with rat and Chinese hamster hsp40. Indirect immunofluorescence revealed that the hsp40 in HeLa cells accumulates in the nucleus, especially in the nucleolus, during heat shock and returns to the cytoplasm during the recovery period. The kinetics of the accumulation in the nucleoli and subsequent return to the cytoplasm of hsp40 was similar to that of hsp70. In addition, hsp40 was co-localized with hsc70(p73) in heat-shocked HeLa cells as demonstrated by double immunofluorescence staining. These results suggest that hsp40 (a DnaJ homologue) and hsp70 (a DnaK homologue) may act in concert to repair (refold) denatured proteins and protein aggregates in the nuclei and nucleoli of heat-shocked HeLa cells.

Original languageEnglish
Pages (from-to)629-638
Number of pages10
JournalJournal of Cell Science
Issue number3
StatePublished - Mar 1 1993
Externally publishedYes



  • Co-localization
  • hsp40 (DnaJ homologue)
  • hsp70 (DnaK homologue)

ASJC Scopus subject areas

  • Cell Biology

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