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NBP 35 interacts with DRE 2 in the maturation of cytosolic iron‐sulphur proteins in Arabidopsis thaliana
Author(s) -
Bastow Emma L.,
Bych Katrine,
Crack Jason C.,
Le Brun Nick E.,
Balk Janneke
Publication year - 2017
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13409
Subject(s) - biology , aconitase , cytosol , biochemistry , arabidopsis thaliana , mutant , arabidopsis , microbiology and biotechnology , gene , enzyme
Summary Proteins of the cytosolic pathway for iron‐sulphur (FeS) cluster assembly are conserved, except that plants lack a gene for CFD 1 (Cytosolic FeS cluster Deficient 1). This poses the question of how NBP 35 (Nucleotide‐Binding Protein 35 kD a), the heteromeric partner of CFD 1 in metazoa, functions on its own in plants. Firstly, we created viable mutant alleles of NBP 35 in Arabidopsis to overcome embryo lethality of previously reported knockout mutations. RNA i knockdown lines with less than 30% NBP 35 protein surprisingly showed no developmental or biochemical differences to wild‐type. Substitution of Cys14 to Ala, which destabilized the N‐terminal Fe 4 S 4 cluster 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 ROS 1 was only partially decreased in activity and xanthine dehydrogenase not at all. Plants with strongly depleted NBP 35 protein in combination with Cys14 to Ala substitution had distorted leaf development and decreased FeS enzyme activities. To find protein interaction partners of NBP 35, a yeast‐two‐hybrid screen was carried out that identified NBP 35 and DRE 2 (Derepressed for Ribosomal protein S14 Expression). NBP 35 is known to form a dimer, and DRE 2 acts upstream in the cytosolic FeS protein assembly pathway. The NBP 35– DRE 2 interaction was not disrupted by Cys14 to Ala substitution. Our results show that NBP 35 has a function in the maturation of FeS proteins that is conserved in plants, and is closely allied to the function of DRE 2.