title: The L-cysteine desulfurase NFS1 is localized in the cytosol where it provides the sulfur for molybdenum cofactor biosynthesis in humans.
abstract: In humans, the L-cysteine desulfurase NFS1 plays a crucial role in the mitochondrial iron-sulfur cluster biosynthesis and in the thiomodification of mitochondrial and cytosolic tRNAs. We have previously demonstrated that purified NFS1 is able to transfer sulfur to the C-terminal domain of MOCS3, a cytosolic protein involved in molybdenum cofactor biosynthesis and tRNA thiolation. However, no direct evidence existed so far for the interaction of NFS1 and MOCS3 in the cytosol of human cells. Here, we present direct data to show the interaction of NFS1 and MOCS3 in the cytosol of human cells using Förster resonance energy transfer and a split-EGFP system. The colocalization of NFS1 and MOCS3 in the cytosol was confirmed by immunodetection of fractionated cells and localization studies using confocal fluorescence microscopy. Purified NFS1 was used to reconstitute the lacking molybdoenzyme activity of the Neurospora crassa nit-1 mutant, giving additional evidence that NFS1 is the sulfur donor for Moco biosynthesis in eukaryotes in general.
authors.affiliation: Department of Molecular Enzymology, Institute of Biochemistry, University of Potsdam, Potsdam, Germany.
authors.forename: Zvonimir
authors.initials: Z
authors.lastname: Marelja
authors.forename: Mita
authors.initials: M
authors.lastname: Mullick Chowdhury
authors.forename: Carsten
authors.initials: C
authors.lastname: Dosche
authors.forename: Carsten
authors.initials: C
authors.lastname: Hille
authors.forename: Otto
authors.initials: O
authors.lastname: Baumann
authors.forename: Hans-Gerd
authors.initials: HG
authors.lastname: Löhmannsröben
authors.forename: Silke
authors.initials: S
authors.lastname: Leimkühler
mesh_terms: D013437:Carbon-Sulfur Lyases / Q000378:metabolism*; D003067:Coenzymes / Q000096:biosynthesis*; D003545:Cysteine / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism*; D031541:Fluorescence Resonance Energy Transfer; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008667:Metalloproteins / Q000096:biosynthesis*; D008856:Microscopy, Fluorescence; D000090006:Molybdenum Cofactors; D050505:Mutant Proteins / Q000378:metabolism; D009491:Neurospora / Q000201:enzymology; D050901:Nitrate Reductase / Q000378:metabolism; D009713:Nucleotidyltransferases / Q000378:metabolism; D025941:Protein Interaction Mapping; D021381:Protein Transport; D011621:Pteridines; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D013455:Sulfur / Q000378:metabolism*; D013466:Sulfurtransferases / Q000378:metabolism; D020349:Surface Plasmon Resonance
chemical_list: D013437:Carbon-Sulfur Lyases; D003067:Coenzymes; D003545:Cysteine; D049452:Green Fluorescent Proteins; D008667:Metalloproteins; D000090006:Molybdenum Cofactors; D050505:Mutant Proteins; D050901:Nitrate Reductase; D009713:Nucleotidyltransferases; D011621:Pteridines; D011993:Recombinant Fusion Proteins; D013455:Sulfur; D013466:Sulfurtransferases; C485184:enhanced green fluorescent protein; C022261:molybdopterin; C502790:MOCS3 protein, human; C513492:NFS1 protein, human