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Structural highlights

Disease

AIFM1_HUMAN Defects in AIFM1 are the cause of combined oxidative phosphorylation deficiency type 6 (COXPD6) [MIM:300816. It is a mitochondrial disease resulting in a neurodegenerative disorder characterized by psychomotor delay, hypotonia, areflexia, muscle weakness and wasting.^{[1] [2]}

Function

MIA40_HUMAN Functions as chaperone and catalyzes the formation of disulfide bonds in substrate proteins, such as COX17. Required for the import and folding of small cysteine-containing proteins (small Tim) in the mitochondrial intermembrane space (IMS). Precursor proteins to be imported into the IMS are translocated in their reduced form into the mitochondria. The oxidized form of CHCHD4/MIA40 forms a transient intermolecular disulfide bridge with the reduced precursor protein, resulting in oxidation of the precursor protein that now contains an intramolecular disulfide bond and is able to undergo folding in the IMS. Reduced CHCHD4/MIA40 is then reoxidized by GFER/ERV1 via a disulfide relay system.^{[3] [4] [5] [6]} AIFM1_HUMAN Probable oxidoreductase that has a dual role in controlling cellular life and death; during apoptosis, it is translocated from the mitochondria to the nucleus to function as a proapoptotic factor in a caspase-independent pathway, while in normal mitochondria, it functions as an antiapoptotic factor via its oxidoreductase activity. The soluble form (AIFsol) found in the nucleus induces 'parthanatos' i.e. caspase-independent fragmentation of chromosomal DNA. Interacts with EIF3G,and thereby inhibits the EIF3 machinery and protein synthesis, and activates casapse-7 to amplify apoptosis. Plays a critical role in caspase-independent, pyknotic cell death in hydrogen peroxide-exposed cells. Binds to DNA in a sequence-independent manner.^{[7] [8] [9]}

References

1. ↑ Ghezzi D, Sevrioukova I, Invernizzi F, Lamperti C, Mora M, D'Adamo P, Novara F, Zuffardi O, Uziel G, Zeviani M. Severe X-linked mitochondrial encephalomyopathy associated with a mutation in apoptosis-inducing factor. Am J Hum Genet. 2010 Apr 9;86(4):639-49. doi: 10.1016/j.ajhg.2010.03.002. Epub, 2010 Apr 1. PMID:20362274 doi:10.1016/j.ajhg.2010.03.002
2. ↑ Berger I, Ben-Neriah Z, Dor-Wolman T, Shaag A, Saada A, Zenvirt S, Raas-Rothschild A, Nadjari M, Kaestner KH, Elpeleg O. Early prenatal ventriculomegaly due to an AIFM1 mutation identified by linkage analysis and whole exome sequencing. Mol Genet Metab. 2011 Dec;104(4):517-20. doi: 10.1016/j.ymgme.2011.09.020. Epub, 2011 Sep 24. PMID:22019070 doi:10.1016/j.ymgme.2011.09.020
3. ↑ Hofmann S, Rothbauer U, Muhlenbein N, Baiker K, Hell K, Bauer MF. Functional and mutational characterization of human MIA40 acting during import into the mitochondrial intermembrane space. J Mol Biol. 2005 Oct 28;353(3):517-28. PMID:16185709 doi:http://dx.doi.org/S0022-2836(05)01031-4
4. ↑ Sztolsztener ME, Brewinska A, Guiard B, Chacinska A. Disulfide bond formation: sulfhydryl oxidase ALR controls mitochondrial biogenesis of human MIA40. Traffic. 2013 Mar;14(3):309-20. doi: 10.1111/tra.12030. Epub 2012 Dec 16. PMID:23186364 doi:http://dx.doi.org/10.1111/tra.12030
5. ↑ Banci L, Bertini I, Cefaro C, Ciofi-Baffoni S, Gallo A, Martinelli M, Sideris DP, Katrakili N, Tokatlidis K. MIA40 is an oxidoreductase that catalyzes oxidative protein folding in mitochondria. Nat Struct Mol Biol. 2009 Feb;16(2):198-206. Epub 2009 Feb 1. PMID:19182799 doi:10.1038/nsmb.1553
6. ↑ Banci L, Bertini I, Cefaro C, Cenacchi L, Ciofi-Baffoni S, Felli IC, Gallo A, Gonnelli L, Luchinat E, Sideris D, Tokatlidis K. Molecular chaperone function of Mia40 triggers consecutive induced folding steps of the substrate in mitochondrial protein import. Proc Natl Acad Sci U S A. 2010 Nov 8. PMID:21059946 doi:10.1073/pnas.1010095107
7. ↑ Kim JT, Kim KD, Song EY, Lee HG, Kim JW, Kim JW, Chae SK, Kim E, Lee MS, Yang Y, Lim JS. Apoptosis-inducing factor (AIF) inhibits protein synthesis by interacting with the eukaryotic translation initiation factor 3 subunit p44 (eIF3g). FEBS Lett. 2006 Nov 27;580(27):6375-83. Epub 2006 Nov 3. PMID:17094969 doi:10.1016/j.febslet.2006.10.049
8. ↑ Son YO, Jang YS, Heo JS, Chung WT, Choi KC, Lee JC. Apoptosis-inducing factor plays a critical role in caspase-independent, pyknotic cell death in hydrogen peroxide-exposed cells. Apoptosis. 2009 Jun;14(6):796-808. doi: 10.1007/s10495-009-0353-7. PMID:19418225 doi:10.1007/s10495-009-0353-7
9. ↑ Ghezzi D, Sevrioukova I, Invernizzi F, Lamperti C, Mora M, D'Adamo P, Novara F, Zuffardi O, Uziel G, Zeviani M. Severe X-linked mitochondrial encephalomyopathy associated with a mutation in apoptosis-inducing factor. Am J Hum Genet. 2010 Apr 9;86(4):639-49. doi: 10.1016/j.ajhg.2010.03.002. Epub, 2010 Apr 1. PMID:20362274 doi:10.1016/j.ajhg.2010.03.002