Functional Analysis of Subunit e of the F₁F_o-ATP Synthase of the Yeast Saccharomyces cerevisiae: Importance of the N-Terminal Membrane Anchor Region

Authors

Valerie Everard-Gigot, Marquette UniversityFollow
Cory D. Dunn, Johns Hopkins University
Brigid M. Dolan, Marquette University
Susanne Brunner, Marquette University
Robert E. Jensen, Johns Hopkins University
Rosemary A. Stuart, Marquette UniversityFollow

Document Type

Article

Language

eng

Publication Date

2-2005

Publisher

American Society for Microbiology

Source Publication

Eukaryotic Cell

Source ISSN

1535-9778

Original Item ID

DOI: 10.1128/EC.4.2.346-355.2005

Abstract

Mitochondrial F₁F_o-ATP synthase complexes do not exist as physically independent entities but rather form dimeric and possibly oligomeric complexes in the inner mitochondrial membrane. Stable dimerization of two F₁F_o-monomeric complexes involves the physical association of two membrane-embedded F_o-sectors. Previously, formation of the ATP synthase dimeric-oligomeric network was demonstrated to play a critical role in modulating the morphology of the mitochondrial inner membrane. In Saccharomyces cerevisiae, subunit e (Su e) of the F_o-sector plays a central role in supporting ATP synthase dimerization. The Su e protein is anchored to the inner membrane via a hydrophobic region located at its N-terminal end. The hydrophilic C-terminal region of Su e resides in the intermembrane space and contains a conserved coiled-coil motif. In the present study, we focused on characterizing the importance of these regions for the function of Su e. We created a number of C-terminal-truncated derivatives of the Su e protein and expressed them in the Su e null yeast mutant. Mitochondria were isolated from the resulting transformant strains, and a number of functions of Su e were analyzed. Our results indicate that the N-terminal hydrophobic region plays important roles in the Su e-dependent processes of mitochondrial DNA maintenance, modulation of mitochondrial morphology, and stabilization of the dimer-specific F_o subunits, subunits g and k. Furthermore, we show that the C-terminal coiled-coil region of Su e functions to stabilize the dimeric form of detergent-solubilized ATP synthase complexes. Finally, we propose a model to explain how Su e supports the assembly of the ATP synthase dimers-oligomers in the mitochondrial membrane.

Comments

Published version. Eukaryotic Cell, Vol. 4, No. 2 (February 2005): 346-355. DOI. © 2005 American Society for Microbiology. Used with permission.

Recommended Citation

Everard-Gigot, Valerie; Dunn, Cory D.; Dolan, Brigid M.; Brunner, Susanne; Jensen, Robert E.; and Stuart, Rosemary A., "Functional Analysis of Subunit e of the F₁F_o-ATP Synthase of the Yeast Saccharomyces cerevisiae: Importance of the N-Terminal Membrane Anchor Region" (2005). Biological Sciences Faculty Research and Publications. 326.
https://epublications.marquette.edu/bio_fac/326