Localization of DnaK and GroEL in Vibrio cholerae

Though the GroEL and DnaK heat shock proteins are well characterized in prokaryotes, only scanty and controversial information exist about their cellular localization. In the present study, the localization of the heat shock proteins DnaK and GroEL in normal and heat shocked cells of Vibrio cholerae, was investigated both by immunogold labeling of ultrathin sections and biochemical methods. Much of the DnaK was found to be localized at the inner membrane in unstressed cells, most probably at the Bayer's adhesion sites. Data suggested that upon heat shock, the DnaK associated with the membrane continued to remain there, but the newly synthesized DnaK appeared mostly in the cytoplasm. GroEL in both stressed and unstressed cells was found mainly in the cytoplasm.