Import and Assembly of the Mitochondrial ATP Synthase of Baker’s Yeast

Abstract

The synthesis of mitochondrial ATPase is programmed by nuclear genes as well as by mitochondrial genes. In Saccharomyces cerevisiae, the coding dichotomy parallels the structural dichotomy of the enzyme: The five F₁ subunits and OSCP are encoded in the nucleus, and the three known F₀ subunits, 6, 9, 10 (also called aap1), are encoded in the mitochondrion. Because formation of both domains is essential if new ATPase complex is to be made, we are investigating the assembly of ATPase and particularly the interaction between nuclear and mitochondrial gene products. Our experiments are of two types: (1) studies of the rate of import and association of the ATPase subunits which are encoded in the nucleus and made in the cytoplasm; and (2) examination of nuclear mutations (suppressors) which compensate for a defect in the mitochondrial gene for an F₀ subunit.