Is there a relationship between the supramolecular organization of the mitochondrial ATP synthase and the formation of cristae?
Blue native polyacrylamide gel electrophoresis (BN-PAGE) analyses of detergent mitochondrial extracts have provided evidence that the yeast ATP synthase could form dimers. Cross-linking experiments performed on a modified version of the i-subunit of this enzyme indicate the existence of such ATP synthase dimers in the yeast inner mitochondrial membrane. We also show that the first transmembrane segment of the eukaryotic b-subunit (bTM1), like the two supernumerary subunits e and g, is required for dimerization/oligomerization of ATP synthases. Unlike mitochondria of wild-type cells that display a well-developed cristae network, mitochondria of yeast cells devoid of subunits e, g, or bTM1 present morphological alterations with an abnormal proliferation of the inner mitochondrial membrane. From these observations, we postulate that an anomalous organization of the inner mitochondrial membrane occurs due to the absence of ATP synthase dimers/oligomers. We provide a model in which the mitochondrial ATP synthase is a key element in cristae morphogenesis.
Institut de Biochimie et Génétique Cellulaires du CNRS, Université Victor Segalen, Bordeaux, France. marie-france.giraud@ibgc.u-bordeaux2.fr
Marie-France
MF
Giraud
Patrick
P
Paumard
Vincent
V
Soubannier
Jacques
J
Vaillier
Geneviève
G
Arselin
Bénédicte
B
Salin
Jacques
J
Schaeffer
Daniel
D
Brèthes
Jean-Paul
JP
di Rago
Jean
J
Velours
D019281:Dimerization; D007425:Intracellular Membranes / Q000737:chemistry / Q000201:enzymology* / Q000648:ultrastructure; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000737:chemistry / Q000201:enzymology* / Q000648:ultrastructure; D025261:Mitochondrial Proton-Translocating ATPases / Q000737:chemistry*; D012441:Saccharomyces cerevisiae
D025261:Mitochondrial Proton-Translocating ATPases