TPN (tetrachloroisophthalonitrile) affected the growth in yeast Saccharomyces cerevisiae and enhanced the superoxide dismutase and glutathione reductase activity under sublethal concentration. Conversely, mild heat-shock treatment had no effect on the enzyme activities. These show they inhibit the metabolism diversely: TPN is an oxidative stressor and mild heat-shock treatment leads to thermogenesis. We have earlier reported that on exposure to TPN under sublethal concentration, heat-shock protein Hsp104 was induced in the same way as in the mild heat-shock treatment (Fujita et al., Biochem. Biophys. Res. Commun. (1995) 216, 1041-1047). However, intracellular localizations of Hsp104 showed different patterns in each treated cell according to immunoelectron microscopic observation. While Hsp104 was localized upon the circumference of the protein aggregates in mild heat-shocked cells, Hsp104 was distributed over the entire TPN-treated cells with no protein aggregates. These findings suggest Hsp104 adaptively responds to comprehensive stress and participates in an emergent rescue function as a molecular chaperone.