We have recently shown that the yeast F1F0-ATP synthase complex exists as a dimer in the mitochondrial inner membrane. Isolation of the dimeric AlP synthase complex led to the identification of three new subunits of the complex. These subunits, Su e, Su g and Su k were found to be specifically associated with the dimeric form of the ATP synthase complex. The present proposal focuses on understanding the formation and function of the ATP synthase dimer. Su e appears to play a central role in the formation of the dimeric ATP synthase. Understanding both the function and the arrangement of Su e, and the other dimer specific-subunits, within the F0-sector represents a major goal of this research proposal. Second, we wish to analyze if the dimeric form of the F1F0-ATPase complex plays a central role in its ability to be inhibited by the natural inhibitor protein, IF1. It has been recently demonstrated that the natural inhibitor protein of the ATPase, IF1 (termed INH 1 in yeast) forms dimers and binds two neighboring F1-domains, concomitantly. We shall analyze whether formation of the dimeric F1F0-ATP synthase, mediated by Su e and Su g, plays a role in maintaining neighboring F1-sectors in close proximity to each other, so as to enable binding of the inhibitor protein dimer. Finally, our preliminary data suggests that the formation of the ATP synthase dimer is important for the maximal activity of the cytochrome oxidase complex. The analysis of the role of the dimeric ATP synthase and possible involvement with the cytochrome oxidase complex is also proposed. Since the assembly and oligomeric state of both of these complexes is anticipated to be similar in all eukaryotes, information gained from these studies should be helpful in the future analysis of human disorders stemming from enzymatic deficiencies in either the F1F0-ATP synthase or cytochrome oxidase complexes.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
Project #
Application #
Study Section
Physical Biochemistry Study Section (PB)
Program Officer
Preusch, Peter C
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Marquette University
Schools of Arts and Sciences
United States
Zip Code
Stuart, Rosemary A (2009) Chapter 11 Supercomplex organization of the yeast respiratory chain complexes and the ADP/ATP carrier proteins. Methods Enzymol 456:191-208
Saddar, Sonika; Dienhart, Mary K; Stuart, Rosemary A (2008) The F1F0-ATP synthase complex influences the assembly state of the cytochrome bc1-cytochrome oxidase supercomplex and its association with the TIM23 machinery. J Biol Chem 283:6677-86
Stuart, Rosemary A (2008) Supercomplex organization of the oxidative phosphorylation enzymes in yeast mitochondria. J Bioenerg Biomembr 40:411-7
Yao, Huili; Stuart, Rosemary A; Cai, Sheng et al. (2008) Structural characterization of the transmembrane domain from subunit e of yeast F1Fo-ATP synthase: a helical GXXXG motif located just under the micelle surface. Biochemistry 47:1910-7
Dienhart, Mary K; Stuart, Rosemary A (2008) The yeast Aac2 protein exists in physical association with the cytochrome bc1-COX supercomplex and the TIM23 machinery. Mol Biol Cell 19:3934-43
Jia, Lixia; Dienhart, Mary K; Stuart, Rosemary A (2007) Oxa1 directly interacts with Atp9 and mediates its assembly into the mitochondrial F1Fo-ATP synthase complex. Mol Biol Cell 18:1897-908
Saddar, Sonika; Stuart, Rosemary A (2005) The yeast F(1)F(0)-ATP synthase: analysis of the molecular organization of subunit g and the importance of a conserved GXXXG motif. J Biol Chem 280:24435-42
Everard-Gigot, Valerie; Dunn, Cory D; Dolan, Brigid M et al. (2005) Functional analysis of subunit e of the F1Fo-ATP synthase of the yeast Saccharomyces cerevisiae: importance of the N-terminal membrane anchor region. Eukaryot Cell 4:346-55
Dienhart, Mary; Pfeiffer, Kathy; Schagger, Hermann et al. (2002) Formation of the yeast F1F0-ATP synthase dimeric complex does not require the ATPase inhibitor protein, Inh1. J Biol Chem 277:39289-95
Brunner, Susanne; Everard-Gigot, Valerie; Stuart, Rosemary A (2002) Su e of the yeast F1Fo-ATP synthase forms homodimers. J Biol Chem 277:48484-9