title: The N-Terminus of Iron-Sulfur Cluster Assembly Factor ISD11 Is Crucial for Subcellular Targeting and Interaction with l-Cysteine Desulfurase NFS1.
abstract: Assembly of iron-sulfur (FeS) clusters is an important process in living cells. The initial sulfur mobilization step for FeS cluster biosynthesis is catalyzed by l-cysteine desulfurase NFS1, a reaction that is localized in mitochondria in humans. In humans, the function of NFS1 depends on the ISD11 protein, which is required to stabilize its structure. The NFS1/ISD11 complex further interacts with scaffold protein ISCU and regulator protein frataxin, thereby forming a quaternary complex for FeS cluster formation. It has been suggested that the role of ISD11 is not restricted to its role in stabilizing the structure of NFS1, because studies of single-amino acid variants of ISD11 additionally demonstrated its importance for the correct assembly of the quaternary complex. In this study, we are focusing on the N-terminal region of ISD11 to determine the role of N-terminal amino acids in the formation of the complex with NFS1 and to reveal the mitochondrial targeting sequence for subcellular localization. Our in vitro studies with the purified proteins and in vivo studies in a cellular system show that the first 10 N-terminal amino acids of ISD11 are indispensable for the activity of NFS1 and especially the conserved "LYR" motif is essential for the role of ISD11 in forming a stable and active complex with NFS1.
authors.affiliation: Institut für Biochemie und Biologie, Molekulare Enzymologie, Universität Potsdam , Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Friemel
authors.affiliation: Imagine Institute, Université Paris Descartes, Sorbonne Paris Cité , 75015 Paris, France.
authors.forename: Zvonimir
authors.initials: Z
authors.lastname: Marelja
authors.affiliation: Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University , Nanjing, China.
authors.forename: Kuanyu
authors.initials: K
authors.lastname: Li
authors.affiliation: Institut für Biochemie und Biologie, Molekulare Enzymologie, Universität Potsdam , Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany.
authors.forename: Silke
authors.identifier: 0000-0003-3238-2122
authors.initials: S
authors.lastname: Leimkühler
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D013437:Carbon-Sulfur Lyases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007501:Iron / Q000737:chemistry* / Q000378:metabolism; D033862:Iron-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D035925:Iron-Regulatory Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D000072417:Protein Domains; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D021381:Protein Transport; D015398:Signal Transduction; D013455:Sulfur / Q000737:chemistry* / Q000378:metabolism; D000096923:Frataxin
chemical_list: D001426:Bacterial Proteins; D013437:Carbon-Sulfur Lyases; D049452:Green Fluorescent Proteins; D007501:Iron; D033862:Iron-Binding Proteins; D035925:Iron-Regulatory Proteins; D007506:Iron-Sulfur Proteins; D008164:Luminescent Proteins; D013455:Sulfur; D000096923:Frataxin; C506160:ISCU protein, human; C544445:LYRM4 protein, human; C054562:yellow fluorescent protein, Bacteria; C513492:NFS1 protein, human