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Structural insights into respiratory complex I deficiency and assembly from the mitochondrial disease-related ndufs4-/- mouse.

Published version
Peer-reviewed

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Abstract

Respiratory complex I (NADH:ubiquinone oxidoreductase) is essential for cellular energy production and NAD+ homeostasis. Complex I mutations cause neuromuscular, mitochondrial diseases, such as Leigh Syndrome, but their molecular-level consequences remain poorly understood. Here, we use a popular complex I-linked mitochondrial disease model, the ndufs4-/- mouse, to define the structural, biochemical, and functional consequences of the absence of subunit NDUFS4. Cryo-EM analyses of the complex I from ndufs4-/- mouse hearts revealed a loose association of the NADH-dehydrogenase module, and discrete classes containing either assembly factor NDUFAF2 or subunit NDUFS6. Subunit NDUFA12, which replaces its paralogue NDUFAF2 in mature complex I, is absent from all classes, compounding the deletion of NDUFS4 and preventing maturation of an NDUFS4-free enzyme. We propose that NDUFAF2 recruits the NADH-dehydrogenase module during assembly of the complex. Taken together, the findings provide new molecular-level understanding of the ndufs4-/- mouse model and complex I-linked mitochondrial disease.

Description

Acknowledgements: This research was funded by the Medical Research Council (MC_UU_00015/2 and MC_UU_00028/1 to JH). We thank Shujing Ding, Ian M. Fearnley and Michael E. Harbour (MBU proteomics facility) for mass spectrometry analyses, James N. Blaza (MBU, now University of York) for assistance with preliminary cryo-EM experiments, Carlo Viscomi for assistance with mouse husbandry, Diamond for access and support of the cryo-EM facilities at the UK national electron Bio-Imaging Centre (eBIC), proposals EM17057-2 and BI22238-4, funded by the Wellcome Trust, MRC, and BBSRC, as well as staff at University of Cambridge cryo-EM facility for grid screening.

Keywords

Complex I, Cryo-EM, Leigh Syndrome, Mitochondria, NADH:Ubiquinone Oxidoreductase, Animals, Mice, Electron Transport Complex I, Leigh Disease, Mitochondria, Mitochondrial Diseases, NAD, NADH Dehydrogenase

Journal Title

EMBO J

Conference Name

Journal ISSN

0261-4189
1460-2075

Volume Title

43

Publisher

Springer Science and Business Media LLC
Sponsorship
MRC (MC_UU_00015/2)
Medical Research Council (MC_UU_00015/7)