Document Type

Article

Publication Date

3-16-2023

Comments

This article is the author's final published version in Proceedings of the National Academy of Sciences of the United States of America, Volume 120, Issue 12, 2023, Article number e2207471120.

The published version is available at https://doi.org/10.1073/pnas.2207471120. Copyright © 2023 the Author(s). Published by PNAS.

Abstract

Inner mitochondrial membrane fusion and cristae shape depend on optic atrophy protein 1, OPA1. Mutations in OPA1 lead to autosomal dominant optic atrophy (ADOA), an important cause of inherited blindness. The Guanosin Triphosphatase (GTPase) and GTPase effector domains (GEDs) of OPA1 are essential for mitochondrial fusion; yet, their specific roles remain elusive. Intriguingly, patients carrying OPA1 GTPase mutations have a higher risk of developing more severe multisystemic symptoms in addition to optic atrophy, suggesting pathogenic contributions for the GTPase and GED domains, respectively. We studied OPA1 GTPase and GED mutations to understand their domain-specific contribution to protein function by analyzing patient-derived cells and gain-of-function paradigms. Mitochondria from OPA1 GTPase (c.870+5G>A and c.889C>T) and GED (c.2713C>T and c.2818+5G>A) mutants display distinct aberrant cristae ultrastructure. While all OPA1 mutants inhibited mitochondrial fusion, some GTPase mutants resulted in elongated mitochondria, suggesting fission inhibition. We show that the GED is dispensable for fusion and OPA1 oligomer formation but necessary for GTPase activity. Finally, splicing defect mutants displayed a posttranslational haploinsufficiency-like phenotype but retained domain-specific dysfunctions. Thus, OPA1 domain-specific mutants result in distinct impairments in mitochondrial dynamics, providing insight into OPA1 function and its contribution to ADOA pathogenesis and severity.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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pnas.2207471120.sapp.pdf (41371 kB)
Appendix 01
pnas.2207471120.sm01.avi (281 kB)
Movie S1.
pnas.2207471120.sm02.avi (413 kB)
Movie s2.

PubMed ID

36927155

Language

English

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