title: NBP35 interacts with DRE2 in the maturation of cytosolic iron-sulphur proteins in Arabidopsis thaliana.
abstract: Proteins of the cytosolic pathway for iron-sulphur (FeS) cluster assembly are conserved, except that plants lack a gene for CFD1 (Cytosolic FeS cluster Deficient 1). This poses the question of how NBP35 (Nucleotide-Binding Protein 35 kDa), the heteromeric partner of CFD1 in metazoa, functions on its own in plants. Firstly, we created viable mutant alleles of NBP35 in Arabidopsis to overcome embryo lethality of previously reported knockout mutations. RNAi knockdown lines with less than 30% NBP35 protein surprisingly showed no developmental or biochemical differences to wild-type. Substitution of Cys14 to Ala, which destabilized the N-terminal Fe4S4cluster in vitro, caused mild growth defects and a significant decrease in the activity of cytosolic FeS enzymes such as aconitase and aldehyde oxidases. The DNA glycosylase ROS1 was only partially decreased in activity and xanthine dehydrogenase not at all. Plants with strongly depleted NBP35 protein in combination with Cys14 to Ala substitution had distorted leaf development and decreased FeS enzyme activities. To find protein interaction partners of NBP35, a yeast-two-hybrid screen was carried out that identified NBP35 and DRE2 (Derepressed for Ribosomal protein S14 Expression). NBP35 is known to form a dimer, and DRE2 acts upstream in the cytosolic FeS protein assembly pathway. The NBP35-DRE2 interaction was not disrupted by Cys14 to Ala substitution. Our results show that NBP35 has a function in the maturation of FeS proteins that is conserved in plants, and is closely allied to the function of DRE2.
authors: John Innes Centre, Norwich, NR4 7UH, UK.|University of East Anglia, Norwich, NR4 7TJ, UK.
authors: Emma L
authors: EL
authors: Bastow
authors: Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK.
authors: Katrine
authors: K
authors: Bych
authors: University of East Anglia, Norwich, NR4 7TJ, UK.
authors: Jason C
authors: JC
authors: Crack
authors: University of East Anglia, Norwich, NR4 7TJ, UK.
authors: Nick E
authors: NE
authors: Le Brun
authors: John Innes Centre, Norwich, NR4 7UH, UK.
authors: Janneke
authors: J
authors: Balk
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D007506:Iron-Sulfur Proteins / Q000235:genetics / Q000378:metabolism*; D020125:Mutation, Missense; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified; D011485:Protein Binding; D034622:RNA Interference; D017386:Sequence Homology, Amino Acid
chemical_list: D029681:Arabidopsis Proteins; D002352:Carrier Proteins; C000597089:DRE2 protein, Arabidopsis; D007506:Iron-Sulfur Proteins; C534471:Nbp35 protein, Arabidopsis; D009687:Nuclear Proteins; C471271:ROS1 protein, Arabidopsis
keywords: 
  Arabidopsis thaliana
  ; CIAPIN1; DNA methylation; Fe-S cofactor; aconitase; aldehyde oxidase; cytosol; leaf development; yeast-two-hybrid