Minimal cytosolic iron‐sulfur cluster assembly machinery of Giardia intestinalis is partially associated with mitosomes

• Published in: Molecular microbiology Vol. 102; no. 4; pp. 701 - 714
• Main Authors: Pyrih, Jan, Pyrihová, Eva, Kolísko, Martin, Stojanovová, Darja, Basu, Somsuvro, Harant, Karel, Haindrich, Alexander C., Doležal, Pavel, Lukeš, Julius, Roger, Andrew, Tachezy, Jan
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.11.2016
• Subjects: Bacteriology; Cytoplasm; Cytosol - metabolism; Eukaryotes; Genomics; Giardia; Giardia intestinalis; Giardia lamblia - genetics; Giardia lamblia - metabolism; Iron - metabolism; Iron-Sulfur Proteins - metabolism; Microbiology; Mitochondria - metabolism; Mitochondrial Proteins - metabolism; Proteins; Sulfur - metabolism
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/mmi.13487

Summary Iron‐sulfur (Fe‐S) clusters are essential cofactors that enable proteins to transport electrons, sense signals, or catalyze chemical reactions. The maturation of dozens of Fe‐S proteins in various compartments of every eukaryotic cell is driven by several assembly pathways. The ubiquitous cytosolic Fe‐S cluster assembly (CIA) pathway, typically composed of eight highly conserved proteins, depends on mitochondrial Fe‐S cluster assembly (ISC) machinery. Giardia intestinalis contains one of the smallest eukaryotic genomes and the mitosome, an extremely reduced mitochondrion. Because the only pathway known to be retained within this organelle is the synthesis of Fe‐S clusters mediated by ISC machinery, a likely function of the mitosome is to cooperate with the CIA pathway. We investigated the cellular localization of CIA components in G. intestinalis and the origin and distribution of CIA‐related components and Tah18‐like proteins in other Metamonada. We show that orthologs of Tah18 and Dre2 are missing in these eukaryotes. In Giardia, all CIA components are exclusively cytosolic, with the important exception of Cia2 and two Nbp35 paralogs, which are present in the mitosomes. We propose that the dual localization of Cia2 and Nbp35 proteins in Giardia might represent a novel connection between the ISC and the CIA pathways. Minimal cytosolic iron‐sulfur cluster assembly (CIA) pathway of Giardia intestinalis comprises of Nbp35, Nar1, Cia1, and Cia2 proteins whereas essential electron donor Tah18/Dre2 complex, as well as Cfd1 and MMS19 seems to be absent in this parasite. In addition to the cytosolic localization, Cia2 and Nbp35 are associated with mitosomes and might represent a novel connection between the mitosomal FeS cluster assembly (ISC) and the CIA pathway.