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Structural highlights

Disease

[ISCU_HUMAN] Hereditary myopathy with lactic acidosis due to ISCU deficiency. The disease is caused by mutations affecting the gene represented in this entry. [NFS1_HUMAN] Severe neonatal lactic acidosis due to NFS1-ISD11 complex deficiency. [LYRM4_HUMAN] Severe neonatal lactic acidosis due to NFS1-ISD11 complex deficiency. The disease is caused by mutations affecting the gene represented in this entry.

Function

[ISCU_HUMAN] Scaffold protein for the de novo synthesis of iron-sulfur (Fe-S) clusters within mitochondria, which is required for maturation of both mitochondrial and cytoplasmic [2Fe-2S] and [4Fe-4S] proteins (PubMed:11060020). First, a [2Fe-2S] cluster is transiently assembled on the scaffold protein ISCU. In a second step, the cluster is released from ISCU, transferred to a glutaredoxin GLRX5, followed by the formation of mitochondrial [2Fe-2S] proteins, the synthesis of [4Fe-4S] clusters and their target-specific insertion into the recipient apoproteins. Cluster assembly on ISCU depends on the function of the cysteine desulfurase complex NFS1-LYRM4/ISD11, which serves as the sulfur donor for cluster synthesis, the iron-binding protein frataxin as the putative iron donor, and the electron transfer chain comprised of ferredoxin reductase and ferredoxin, which receive their electrons from NADH (By similarity).[UniProtKB:Q03020]^[1] [NFS1_HUMAN] Catalyzes the removal of elemental sulfur from cysteine to produce alanine. It supplies the inorganic sulfur for iron-sulfur (Fe-S) clusters. May be involved in the biosynthesis of molybdenum cofactor.^[2] [ACP_ECO45] Carrier of the growing fatty acid chain in fatty acid biosynthesis.[HAMAP-Rule:MF_01217] [LYRM4_HUMAN] Required for nuclear and mitochondrial iron-sulfur protein biosynthesis.^{[3] [4]}

See Also

• Acyl carrier protein 3D structures
• Cysteine desulfurase 3D structures

References

1. ↑ Tong WH, Rouault T. Distinct iron-sulfur cluster assembly complexes exist in the cytosol and mitochondria of human cells. EMBO J. 2000 Nov 1;19(21):5692-700. PMID:11060020 doi:http://dx.doi.org/10.1093/emboj/19.21.5692
2. ↑ Marelja Z, Stocklein W, Nimtz M, Leimkuhler S. A novel role for human Nfs1 in the cytoplasm: Nfs1 acts as a sulfur donor for MOCS3, a protein involved in molybdenum cofactor biosynthesis. J Biol Chem. 2008 Sep 12;283(37):25178-85. doi: 10.1074/jbc.M804064200. Epub 2008, Jul 23. PMID:18650437 doi:http://dx.doi.org/10.1074/jbc.M804064200
3. ↑ Shan Y, Napoli E, Cortopassi G. Mitochondrial frataxin interacts with ISD11 of the NFS1/ISCU complex and multiple mitochondrial chaperones. Hum Mol Genet. 2007 Apr 15;16(8):929-41. Epub 2007 Mar 1. PMID:17331979 doi:http://dx.doi.org/ddm038
4. ↑ Shi Y, Ghosh MC, Tong WH, Rouault TA. Human ISD11 is essential for both iron-sulfur cluster assembly and maintenance of normal cellular iron homeostasis. Hum Mol Genet. 2009 Aug 15;18(16):3014-25. doi: 10.1093/hmg/ddp239. Epub 2009 May, 18. PMID:19454487 doi:http://dx.doi.org/10.1093/hmg/ddp239
5. ↑ Boniecki MT, Freibert SA, Muhlenhoff U, Lill R, Cygler M. Structure and functional dynamics of the mitochondrial Fe/S cluster synthesis complex. Nat Commun. 2017 Nov 3;8(1):1287. doi: 10.1038/s41467-017-01497-1. PMID:29097656 doi:http://dx.doi.org/10.1038/s41467-017-01497-1