FBXL4 ubiquitin ligase deficiency promotes mitophagy by elevating NIX levels.



Elcocks, Hannah, Brazel, Ailbhe J, McCarron, Katy R, Kaulich, Manuel, Husnjak, Koraljka, Mortiboys, Heather, Clague, Michael J ORCID: 0000-0003-3355-9479 and Urbé, Sylvie
(2023) FBXL4 ubiquitin ligase deficiency promotes mitophagy by elevating NIX levels. The EMBO journal, 42 (13). e112799-e112799.

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Abstract

Selective autophagy of mitochondria, mitophagy, is linked to mitochondrial quality control and as such is critical to a healthy organism. We have used a CRISPR/Cas9 approach to screen human E3 ubiquitin ligases for influence on mitophagy under both basal cell culture conditions and upon acute mitochondrial depolarization. We identify two cullin-RING ligase substrate receptors, VHL and FBXL4, as the most profound negative regulators of basal mitophagy. We show that these converge, albeit via different mechanisms, on control of the mitophagy adaptors BNIP3 and BNIP3L/NIX. FBXL4 restricts NIX and BNIP3 levels via direct interaction and protein destabilization, while VHL acts through suppression of HIF1α-mediated transcription of BNIP3 and NIX. Depletion of NIX but not BNIP3 is sufficient to restore mitophagy levels. Our study contributes to an understanding of the aetiology of early-onset mitochondrial encephalomyopathy that is supported by analysis of a disease-associated mutation. We further show that the compound MLN4924, which globally interferes with cullin-RING ligase activity, is a strong inducer of mitophagy, thus providing a research tool in this context and a candidate therapeutic agent for conditions linked to mitochondrial dysfunction.

Item Type: Article
Uncontrolled Keywords: BNIP3, FBXL4, mitophagy, NIX, VHL
Divisions: Faculty of Health and Life Sciences
Faculty of Health and Life Sciences > Institute of Systems, Molecular and Integrative Biology
Depositing User: Symplectic Admin
Date Deposited: 05 May 2023 09:10
Last Modified: 25 Dec 2023 03:03
DOI: 10.15252/embj.2022112799
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3170211