Two Subunits of the FoF1-ATPase Are Phosphorylated in the Inner Mitochondrial Membrane

Abstract

Inside-out submitochondrial particles from potato tuber mitochondria were incubated with [γ-32P]ATP. More than 16 phosphorylated polypeptides were detected by autoradiography on an SDS-gel. Two phosphoproteins, migrating at 22 and 28 kDa, were excised from the SDS-gel, electroeluted, and purified further by anion chromatography. The phosphoproteins were N-terminally sequenced. Over the regions sequenced, the 22 and 28 kDa phosphoproteins had 100% sequence identity with potato proteins identified as the δ’-subunit of the F1-ATPase and theb-subunit of the FoATPase, respectively. We suggest that phosphorylation of these proteins may control the interaction between F1and Foand regulate energy coupling in oxidative phosphorylation.