TY - JOUR
T1 - Functional analysis of subunit e of the F1Fo-ATP synthase of the yeast Saccharomyces cerevisiae
T2 - Importance of the N-terminal membrane anchor region
AU - Everard-Gigot, Valerie
AU - Dunn, Cory D.
AU - Dolan, Brigid M.
AU - Brunner, Susanne
AU - Jensen, Robert E.
AU - Stuart, Rosemary A.
PY - 2005/2
Y1 - 2005/2
N2 - 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 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 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.
AB - 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 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 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.
UR - http://www.scopus.com/inward/record.url?scp=13844311432&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=13844311432&partnerID=8YFLogxK
U2 - 10.1128/EC.4.2.346-355.2005
DO - 10.1128/EC.4.2.346-355.2005
M3 - Article
C2 - 15701797
AN - SCOPUS:13844311432
SN - 1535-9778
VL - 4
SP - 346
EP - 355
JO - Eukaryotic Cell
JF - Eukaryotic Cell
IS - 2
ER -