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Mitochondrial Isa2p plays a crucial role in the maturation of cellular iron–sulfur proteins
Author(s) -
Pelzer Winfried,
Mühlenhoff Ulrich,
Diekert Kerstin,
Siegmund Kerstin,
Kispal Gyula,
Lill Roland
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01711-7
Subject(s) - saccharomyces cerevisiae , mitochondrion , mitochondrial matrix , cytosol , biochemistry , gene , hspa9 , yeast , dnaja3 , microbiology and biotechnology , biology , iron binding proteins , function (biology) , iron–sulfur cluster , mitochondrial dna , mitochondrial fusion , chemistry , peptide sequence , enzyme
The assembly of iron–sulfur (Fe/S) clusters in a living cell is mediated by a complex machinery which, in eukaryotes, is localised within mitochondria. Here, we report on a new component of this machinery, the protein Isa2p of the yeast Saccharomyces cerevisiae . The protein shares sequence similarity with yeast Isa1p and the bacterial IscA proteins which recently have been shown to perform a function in Fe/S cluster biosynthesis. Like the Isa1p homologue, Isa2p is localised in the mitochondrial matrix as a soluble protein. Deletion of the ISA2 gene results in the loss of mitochondrial DNA and a strong growth defect. Simultaneous deletion of the ISA1 gene does not further exacerbate this growth phenotype suggesting that the Isa proteins perform a non‐essential function. When Isa2p was depleted by regulated gene expression, mtDNA was maintained, but cells grew slowly on non‐fermentable carbon sources. The maturation of both mitochondrial and cytosolic Fe/S proteins was strongly impaired in the absence of Isa2p. Thus, Isa2p is a new member of the Fe/S cluster biosynthesis machinery of the mitochondrial matrix and may be involved in the binding of an intermediate of Fe/S cluster assembly.