THE FUNCTIONAL EXPRESSION OF A RAT CDNA-ENCODING OSCP IN THE YEAST SACCHAROMYCES-CEREVISIAE

The oligomycin sensitivity conferring protein (OSCP) of Saccharomyces cerevisiae is a component of the stalk F-A sector of the mitochondrial F1F0-ATP synthase complex (mtATPase). The subunits comprising this se ctor have been implicated in the coupling of proton flux through the m embrane F-0 sector to ATP synthesis on the catalytic F-1 sector. We te sted whether the yeast subunit encoded by the ATP5 gene could be funct ionally replaced by a mammalian homologue, rat OSCP. The yeast and rat OSCP proteins have 58% homology in terms of conserved amino acids. A vector-borne rat cDNA encoding the OSCP precursor was introduced into a yeast strain lacking endogenous OSCP as a result of its disrupted AT P5 gene. The resultant yeast cells showed essentially a wildtype growt h rate at 18, 28 and 35 degrees C, on nonfermentable substrates. Expre ssion of mammalian F-A subunit homologues in yeast should provide a pr oductive new approach to generating information on the structure and f unction of mtATPase. (C) 1995 Academic Press, Inc.