Simultaneous depletion of Atm and Mdl rebalances cytosolic Fe-S cluster assembly but not heme import into the mitochondrion of Trypanosoma brucei
Language English Country England, Great Britain Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
26277108
DOI
10.1111/febs.13411
Knihovny.cz E-resources
- Keywords
- Atm, Fe-S cluster, Mdl, Trypanosoma, heme,
- MeSH
- ATP-Binding Cassette Transporters antagonists & inhibitors genetics metabolism MeSH
- Aconitate Hydratase metabolism MeSH
- Models, Biological MeSH
- Cytosol metabolism MeSH
- Fumarate Hydratase metabolism MeSH
- Phylogeny MeSH
- Gene Knockdown Techniques MeSH
- Heme metabolism MeSH
- Mitochondria metabolism MeSH
- Iron-Sulfur Proteins metabolism MeSH
- Multidrug Resistance-Associated Proteins antagonists & inhibitors genetics metabolism MeSH
- Genes, Protozoan MeSH
- Protozoan Proteins antagonists & inhibitors genetics metabolism MeSH
- Saccharomyces cerevisiae genetics metabolism MeSH
- Genetic Complementation Test MeSH
- Trypanosoma brucei brucei genetics metabolism MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- ATP-Binding Cassette Transporters MeSH
- Aconitate Hydratase MeSH
- Fumarate Hydratase MeSH
- Heme MeSH
- Iron-Sulfur Proteins MeSH
- Multidrug Resistance-Associated Proteins MeSH
- Protozoan Proteins MeSH
ABC transporter mitochondrial 1 (Atm1) and multidrug resistance-like 1 (Mdl) are mitochondrial ABC transporters. Although Atm1 was recently suggested to transport different forms of glutathione from the mitochondrion, which are used for iron-sulfur (Fe-S) cluster maturation in the cytosol, the function of Mdl remains elusive. In Trypanosoma brucei, we identified one homolog of each of these genes, TbAtm and TbMdl, which were downregulated either separately or simultaneously using RNA interference. Individual depletion of TbAtm and TbMdl led to limited growth defects. In cells downregulated for TbAtm, the enzymatic activities of the Fe-S cluster proteins aconitase and fumarase significantly decreased in the cytosol but not in the mitochondrion. Downregulation of TbMdl did not cause any change in activities of the Fe-S proteins. Unexpectedly, the simultaneous downregulation of TbAtm and TbMdl did not result in any growth defect, nor were the Fe-S cluster protein activities altered in either the cytosolic or mitochondrial compartments. Additionally, TbAtm and TbMdl were able to partially restore the growth of the Saccharomyces cerevisiae Δatm1 and Δmdl2 null mutants, respectively. Because T. brucei completely lost the heme b biosynthesis pathway, this cofactor has to be obtained from the host. Based on our results, TbMdl is a candidate for mitochondrial import of heme b, which was markedly decreased in both TbMdl and TbAtm + TbMdl knockdowns. Moreover, the levels of heme a were strongly decreased in the same knockdowns, suggesting that TbMdl plays a key role in heme a biosynthesis, thus affecting the overall heme homeostasis in T. brucei.
Biology Centre Institute of Parasitology Czech Academy of Sciences České Budějovice Czech Republic
Canadian Institute for Advanced Research Toronto Ontario Canada
Faculty of Sciences University of South Bohemia České Budějovice Czech Republic
References provided by Crossref.org
Combinatorial interplay of RNA-binding proteins tunes levels of mitochondrial mRNA in trypanosomes
Branched late-steps of the cytosolic iron-sulphur cluster assembly machinery of Trypanosoma brucei
Fe-S cluster assembly in the supergroup Excavata
