title: Loss of apoptosis-inducing factor critically affects MIA40 function.
abstract: Mitochondrial apoptosis-inducing factor (AIF) influences the oxidative phosphorylation (OXPHOS) system and can be recruited as a mediator of cell death. Pathogenic mutations in the AIFM1 gene cause severe human diseases. Clinical manifestations include inherited peripheral neuropathies, prenatal cerebral abnormalities and progressive mitochondrial encephalomyopathies. In humans, rodents and invertebrates, AIF deficiency results in loss of respiratory complexes and, therefore, impaired OXPHOS. The molecular mechanisms underlying AIF-induced mitochondrial dysfunction remain elusive. Here we show that AIF physically interacts with the oxidoreductase CHCHD4/MIA40. In patient-derived fibroblasts as well as in tissues and glia cells from Harlequin (Hq) mutant mice, AIF deficiency correlates with decreased MIA40 protein levels, without affecting mRNA transcription. Importantly, MIA40 overexpression counteracts loss of respiratory subunits in Hq cells. Together, our findings suggest that MIA40 reduction contributes to the effects of AIF deficiency on OXPHOS, as it may impact on the correct assembly and maintenance of the respiratory subunits. This may be relevant for the development of new therapeutic approaches for AIF-related mitochondrial disorders.
authors.affiliation: German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Meyer
authors.affiliation: German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Buettner
authors.affiliation: IRCCS Foundation Institute of Neurology 'C. Besta', Milan, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Ghezzi
authors.affiliation: MRC Mitochondrial Biology Unit, Cambridge, UK.
authors.forename: M
authors.initials: M
authors.lastname: Zeviani
authors.affiliation: German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Bano
authors.affiliation: German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Nicotera
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D051033:Apoptosis Inducing Factor / Q000172:deficiency / Q000235:genetics*; D006801:Humans; D051379:Mice; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000235:genetics*; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D010085:Oxidative Phosphorylation
chemical_list: D051033:Apoptosis Inducing Factor; C507282:CHCHD4 protein, human; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; C494830:AIFM1 protein, mouse