The cyclin-dependent phosphoprotein kinase Pho85p is involved in the regulation of metabolism and cell cycle in the yeast Saccharomyces cerevisiae. It is known that mutations in the PHO85 gene lead to constitutive synthesis of Pho5p acidic phosphatase, a delay in cell growth on media containing nonfermentable carbon sources, sensitivity to high temperature, and other phenotypic effects. A lack of growth at 37 degrees C and on a medium with alcohol as the carbon source was shown to be associated with the rapid accumulation of nuclear ts and mitochondrial [rho-] mutations occurring in the background of gene PHO85 inactivation. Thus, Pho85p seems to play an important role in the maintenance of yeast genome stability.