Effect of amiodarone on thermotolerance and Hsp104p synthesis in the yeast Saccharomyces cerevisiae

Amiodarone (AMD) is known to induce a transient increase in cytosolic Ca²⁺ level in cells of the yeast Saccharomyces cerevisiae. In the present study the effect of AMD on the thermotolerance and Hsp104p synthesis of the yeast was studied. AMD induced Hsp104p synthesis and increased survival of the yeast after a severe heat shock (50°C). The development of thermotolerance to a considerable extent depended on the presence of Hsp104p. The same effect was achieved by treatment with the classical uncoupler CCCP, which is also known to increase the cytosolic Ca²⁺ level. It is supposed that the change in intracellular Ca²⁺ concentration plays an important role in activation of the HSP104 gene expression and in increasing the thermotolerance of the yeast. The possible link between mitochondrial activity and calcium homeostasis is discussed.