The Modulation in Subunits e and g Amounts of Yeast ATP Synthase Modifies Mitochondrial Cristae Morphology

Subunits e and g of Saccharomyces cerevisiae ATP synthase are required to maintain ATP synthase dimeric forms. Mutants devoid of these subunits display anomalous mitochondrial morphologies. An expression system regulated by doxycycline was used to modulate the expression of the genes encoding the subunits e and g. A decrease in the amount of subunit e induces a decrease in the amount of subunit g, but a decrease in the amount of subunit g does not affect subunit e. The loss of subunit e or g leads to the loss of supramolecular structures of ATP synthase, which is fully reversible upon removal of doxycycline. In the absence of doxycycline, mitochondria present poorly defined cristae. In the presence of doxycycline, onion-like structures are formed after five generations. When doxycycline is removed after five generations, cristae are mainly observed. The data demonstrate that the inner structure of mitochondria depends upon the ability of ATP synthase to make supramolecular structures.