Medical College of Wisconsin
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Oxa1 directly interacts with Atp9 and mediates its assembly into the mitochondrial F1Fo-ATP synthase complex. Mol Biol Cell 2007 May;18(5):1897-908



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The yeast Oxa1 protein is involved in the biogenesis of the mitochondrial oxidative phosphorylation (OXPHOS) machinery. The involvement of Oxa1 in the assembly of the cytochrome oxidase (COX) complex, where it facilitates the cotranslational membrane insertion of mitochondrially encoded COX subunits, is well documented. In this study we have addressed the role of Oxa1, and its sequence-related protein Cox18/Oxa2, in the biogenesis of the F(1)F(o)-ATP synthase complex. We demonstrate that Oxa1, but not Cox18/Oxa2, directly supports the assembly of the membrane embedded F(o)-sector of the ATP synthase. Oxa1 was found to physically interact with newly synthesized mitochondrially encoded Atp9 protein in a posttranslational manner and in a manner that is not dependent on the C-terminal, matrix-localized region of Oxa1. The stable manner of the Atp9-Oxa1 interaction is in contrast to the cotranslational and transient interaction previously observed for the mitochondrially encoded COX subunits with Oxa1. In the absence of Oxa1, Atp9 was observed to assemble into an oligomeric complex containing F(1)-subunits, but its further assembly with subunit 6 (Atp6) of the F(o)-sector was perturbed. We propose that by directly interacting with newly synthesized Atp9 in a posttranslational manner, Oxa1 is required to maintain the assembly competence of the Atp9-F(1)-subcomplex for its association with Atp6.

Author List

Jia L, Dienhart MK, Stuart RA


Rosemary Stuart PhD Professor in the Biology department at Marquette University

MESH terms used to index this publication - Major topics in bold

Electron Transport Complex IV
Genes, Fungal
Membrane Proteins
Membrane Transport Proteins
Mitochondrial Proteins
Mitochondrial Proton-Translocating ATPases
Multiprotein Complexes
Nuclear Proteins
Oxidative Phosphorylation
Protein Processing, Post-Translational
Saccharomyces cerevisiae
Saccharomyces cerevisiae Proteins
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a