title: Loss of mitochondrial ATP synthase subunit beta (Atp2) alters mitochondrial and chloroplastic function and morphology in Chlamydomonas.
abstract: Mitochondrial F1FO ATP synthase (Complex V) catalyses ATP synthesis from ADP and inorganic phosphate using the proton-motive force generated by the substrate-driven electron transfer chain. In this work, we investigated the impact of the loss of activity of the mitochondrial enzyme in a photosynthetic organism. In this purpose, we inactivated by RNA interference the expression of the ATP2 gene, coding for the catalytic subunit beta, in the green alga Chlamydomonas reinhardtii. We demonstrate that in the absence of beta subunit, complex V is not assembled, respiratory rate is decreased by half and ATP synthesis coupled to the respiratory activity is fully impaired. Lack of ATP synthase also affects the morphology of mitochondria which are deprived of cristae. We also show that mutants are obligate phototrophs and that rearrangements of the photosynthetic apparatus occur in the chloroplast as a response to ATP synthase deficiency in mitochondria. Altogether, our results contribute to the understanding of the yet poorly studied bioenergetic interactions between organelles in photosynthetic organisms.
authors.affiliation: Laboratoire de Génétique des microorganismes, B22, Institut de Botanique, Université de Liège, B-4000 Liège, Belgium.
authors.forename: Marie
authors.initials: M
authors.lastname: Lapaille
authors.forename: Marc
authors.initials: M
authors.lastname: Thiry
authors.forename: Emilie
authors.initials: E
authors.lastname: Perez
authors.forename: Diego
authors.initials: D
authors.lastname: González-Halphen
authors.forename: Claire
authors.initials: C
authors.lastname: Remacle
authors.forename: Pierre
authors.initials: P
authors.lastname: Cardol
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D002696:Chlamydomonas / Q000502:physiology*; D002736:Chloroplasts / Q000502:physiology* / Q000648:ultrastructure; D008928:Mitochondria / Q000502:physiology*; D025261:Mitochondrial Proton-Translocating ATPases / Q000235:genetics / Q000502:physiology*; D010788:Photosynthesis; D021122:Protein Subunits
chemical_list: D021122:Protein Subunits; D000255:Adenosine Triphosphate; D025261:Mitochondrial Proton-Translocating ATPases