Yeast cells depleted in Atp14p fail to assemble Atp6p within the ATP synthase and exhibit altered mitochondrial cristae morphology.
Within the yeast mitochondrial ATP synthase, subunit h is a small nuclear encoded protein belonging to the so-called "peripheral stalk" that connects the enzyme catalytic F(1) component to the mitochondrial inner membrane. This study examines the role of subunit h in ATP synthase function and assembly using a regulatable, doxycycline-repressible subunit h gene to overcome the strong instability of the mtDNA previously observed in strains lacking the native subunit h gene. Yeast cells expressing less than 3% of subunit h, but still containing intact mitochondrial genomes, grew poorly on respiratory substrates because of a major impairment of ATP synthesis originating from the ATP synthase, whereas the respiratory chain complexes were not affected. The lack of ATP synthesis in the subunit h-depleted (deltah) mitochondria was attributed to defects in the assembly/stability of the ATP synthase. A main feature of deltah-mitochondria was a very low content (<6%) in the mitochondrially encoded Atp6p subunit, an essential component of the enzyme proton channel, which was in large part because of a slowing down in translation. Interestingly, depletion of subunit h resulted in dramatic changes in mitochondrial cristae morphology, which further supports the existence of a link between the ATP synthase and the folding/biogenesis of the inner mitochondrial membrane.
Goyon
Vanessa
V
Université Victor Segalen Bordeaux 2, CNRS Institut de Biochimie et Génétique Cellulaires, Centre National de Recherche Scientifique/UMR 5095, 1 Rue Camille Saint-Saëns, Bordeaux Cedex, France.
Fronzes
Rémi
R
Salin
Bénédicte
B
di-Rago
Jean-Paul
JP
Velours
Jean
J
Brèthes
Daniel
D
D000255:Adenosine Triphosphate / Q000096:biosynthesis / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000201:enzymology* / Q000235:genetics; D051336:Mitochondrial Membranes / Q000201:enzymology*; D025261:Mitochondrial Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
C501004:ATP6 protein, S cerevisiae; D004271:DNA, Fungal; D004272:DNA, Mitochondrial; D029701:Saccharomyces cerevisiae Proteins; D000255:Adenosine Triphosphate; C101128:ATP14 protein, S cerevisiae; D025261:Mitochondrial Proton-Translocating ATPases