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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 2005 Feb;4(2):346-55

Date

02/11/2005

Pubmed ID

15701797

Pubmed Central ID

PMC549337

DOI

10.1128/EC.4.2.346-355.2005

Abstract

Mitochondrial F1Fo-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 F1Fo-monomeric complexes involves the physical association of two membrane-embedded Fo-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 Fo-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 Fo 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.

Author List

Everard-Gigot V, Dunn CD, Dolan BM, Brunner S, Jensen RE, Stuart RA

Author

Rosemary Stuart PhD Professor in the Biology department at Marquette University




MESH terms used to index this publication - Major topics in bold

DNA, Mitochondrial
Dimerization
Intracellular Membranes
Mitochondria
Mitochondrial Proton-Translocating ATPases
Protein Conformation
Protein Structure, Tertiary
Saccharomyces cerevisiae
Saccharomyces cerevisiae Proteins
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a