Protein overexpert in a Saccharomyces cerevisiae mutant depends on mitochondrial genome integrity and function

The wild-type yeast Saccharomyces cerevisiae (S. cerevisiae) is able to exp ort less than 1 percent of the protein to be secreted. The reasons for rete ntion of most of the secretory proteins on the cell surface of S. cerevisia e are unknown. Recently, temperature-sensitive (ts) mutants of S, cerevisia e showing an oversecretion phenotype were isolated. In order to study the i nfluence of the mitochondrial genome status on protein export in yeast cell s, we have isolated several types of respiratory impaired mitochondrial mut ants of either the parental S. cerevisiae strain or their derivative ts pro tein-overexporting mutants. In this paper we demonstrate by quantitative an alyses of exported proteins and by SDS-PAGE analysis that protein over-expo rt in ts mutants requires mitochondrial genome integrity and function.