title: Overlapping binding sites of the frataxin homologue assembly factor and the heat shock protein 70 transfer factor on the Isu iron-sulfur cluster scaffold protein.
abstract: In mitochondria FeS clusters, prosthetic groups critical for the activity of many proteins, are first assembled on Isu, a 14-kDa scaffold protein, and then transferred to recipient apoproteins. The assembly process involves interaction of Isu with both Nfs1, the cysteine desulfurase serving as a sulfur donor, and the yeast frataxin homolog (Yfh1) serving as a regulator of desulfurase activity and/or iron donor. Here, based on the results of biochemical experiments with purified wild-type and variant proteins, we report that interaction of Yfh1 with both Nfs1 and Isu are required for formation of a stable tripartite assembly complex. Disruption of either Yfh1-Isu or Nfs1-Isu interactions destabilizes the complex. Cluster transfer to recipient apoprotein is known to require the interaction of Isu with the J-protein/Hsp70 molecular chaperone pair, Jac1 and Ssq1. Here we show that the Yfh1 interaction with Isu involves the PVK sequence motif, which is also the site key for the interaction of Isu with Hsp70 Ssq1. Coupled with our previous observation that Nfs1 and Jac1 binding to Isu is mutually exclusive due to partially overlapping binding sites, we propose that such mutual exclusivity of cluster assembly factor (Nfs1/Yfh1) and cluster transfer factor (Jac1/Ssq1) binding to Isu has functional consequences for the transition from the assembly process to the transfer process, and thus regulation of the biogenesis of FeS cluster proteins.
authors.affiliation: Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk 80822, Poland and.
authors.forename: Mateusz
authors.initials: M
authors.lastname: Manicki
authors.affiliation: Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk 80822, Poland and; Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706.
authors.forename: Julia
authors.initials: J
authors.lastname: Majewska
authors.affiliation: Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706.
authors.forename: Szymon
authors.initials: S
authors.lastname: Ciesielski
authors.affiliation: Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706.
authors.forename: Brenda
authors.initials: B
authors.lastname: Schilke
authors.affiliation: Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk 80822, Poland and.
authors.forename: Anna
authors.initials: A
authors.lastname: Blenska
authors.affiliation: Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk 80822, Poland and.
authors.forename: Jacek
authors.initials: J
authors.lastname: Kominek
authors.affiliation: Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk 80822, Poland and; Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706. Electronic address: jaroslaw.marszalek@biotech.ug.edu.pl.
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Marszalek
authors.affiliation: Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706. Electronic address: ecraig@wisc.edu.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Craig
authors.affiliation: Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk 80822, Poland and.
authors.forename: Rafal
authors.initials: R
authors.lastname: Dutkiewicz
mesh_terms: D020816:Amino Acid Motifs; D019943:Amino Acid Substitution; D001665:Binding Sites; D017124:Conserved Sequence; D033862:Iron-Binding Proteins / Q000737:chemistry*; D007506:Iron-Sulfur Proteins; D024101:Mitochondrial Proteins / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics; D013466:Sulfurtransferases / Q000737:chemistry* / Q000235:genetics; D000096923:Frataxin
chemical_list: D033862:Iron-Binding Proteins; D007506:Iron-Sulfur Proteins; D024101:Mitochondrial Proteins; D029701:Saccharomyces cerevisiae Proteins; D013466:Sulfurtransferases; D000096923:Frataxin; C121520:ISU1 protein, S cerevisiae; C115912:NFS1 protein, S cerevisiae
keywords: Frataxin; Iron-Sulfur Protein; Mitochondria; Molecular Chaperone; Protein-Protein Interaction; Saccharomyces cerevisiae