Phylogenetic affinity of a<i>Giardia lamblia</i>cysteine desulfurase conforms to canonical pattern of mitochondrial ancestry

Emelyanov, V. V.

doi:10.1016/s0378-1097(03)00598-6

Cited by 24 publications

(23 citation statements)

References 40 publications

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“…Detection of two genes in T. vaginalis coding for IscS homologs with putative hydrogenosomal import signals suggested that FeS-center assembly in hydrogenosomes might be homologous to the mitochondrial system (24). The clustering of the derived amino acid sequences with mitochondrial homologs in phylogenetic reconstructions strengthened this notion further (24,25). Here, we show that one of these genes (tviscS-2) is expressed, translocated to hydrogenosomes, and involved in the biosynthesis of FeS proteins.…”

supporting

confidence: 56%

“…Although the data are scanty, the answer is probably yes. In all of the amitochondriate organisms studied so far, a gene encoding an IscS homolog has been recognized and found to be part of the clade formed by typical mitochondrial homologs (24,25,43). It should be stressed that the studied amitochondriate groups belong to separate taxonomic lineages.…”

Section: Discussionmentioning

confidence: 98%

“…A key enzyme of this process, cysteine desulfurase (TviscS), as well as the process of FeS-center assembly, could be localized in the hydrogenosomes. TviscS-2 also has an putative N-terminal targeting sequence similar to that of other hydrogenosomal proteins and is found in a well supported clade with its mitochondrial homologs in phylogenetic reconstructions (24,25). Hydrogenosome-mediated formation of [FeS] clusters in vitro was demonstrated based on [FeS] cluster reconstitution in recombinant T. vaginalis apoferredoxin by using 35 S-cysteine as a source of S under anaerobic conditions.…”

Section: Discussionmentioning

confidence: 99%

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Mitochondrial-type assembly of FeS centers in the hydrogenosomes of the amitochondriate eukaryote Trichomonas vaginalis

Šuták

Doležal

Fiumera

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

146

106

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Mitochondria are the site of assembly of FeS centers of mitochondrial and cytosolic FeS proteins. Various microaerophilic or anaerobic unicellular eukaryotes lack typical mitochondria (''amitochondriate'' protists). In some of these organisms, a metabolically different organelle, the hydrogenosome, is found, which is thought to derive from the same proteobacterial ancestor as mitochondria. Here, we show that hydrogenosomes of Trichomonas vaginalis, a human genitourinary parasite, contain a key enzyme of FeS center biosynthesis, cysteine desulfurase (TviscS-2), which is phylogenetically related to its mitochondrial homologs. Hydrogenosomes catalyze the enzymatic assembly and insertion of FeS centers into apoproteins, as shown by the reconstruction of the apoform of [2Fe-2S]ferredoxin and the incorporation of 35 S from labeled cysteine. Our results indicate that the biosynthesis of FeS proteins is performed by a homologous system in mitochondriate and amitochondriate eukaryotes and that this process is inherited from the proteobacterial ancestor of mitochondria.

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supporting

confidence: 56%

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

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Mitochondrial-type assembly of FeS centers in the hydrogenosomes of the amitochondriate eukaryote Trichomonas vaginalis

Šuták

Doležal

Fiumera

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

146

106

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“…Key proteins in this pathway; cysteine desulphurase (IscS) and scaffolding protein (IscU), appear to have originated from the mitochondrial endosymbiont (Tachezy et al 2001;Emelyanov 2003;van der Giezen et al 2004). The maturation and export of Fe/S clusters has been suggested as a possible common function of all mitochondrial homologues (Tachezy et al 2001;Embley et al 2003a).…”

Section: Conclusion Speculations and Outlookmentioning

confidence: 99%

Multiple secondary origins of the anaerobic lifestyle in eukaryotes

Embley

2006

Phil. Trans. R. Soc. B

111

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Classical ideas for early eukaryotic evolution often posited a period of anaerobic evolution producing a nucleated phagocytic cell to engulf the mitochondrial endosymbiont, whose presence allowed the host to colonize emerging aerobic environments. This idea was given credence by the existence of contemporary anaerobic eukaryotes that were thought to primitively lack mitochondria, thus providing examples of the type of host cell needed. However, the groups key to this hypothesis have now been shown to contain previously overlooked mitochondrial homologues called hydrogenosomes or mitosomes; organelles that share common ancestry with mitochondria but which do not carry out aerobic respiration. Mapping these data on the unfolding eukaryotic tree reveals that secondary adaptation to anaerobic habitats is a reoccurring theme among eukaryotes. The apparent ubiquity of mitochondrial homologues bears testament to the importance of the mitochondrial endosymbiosis, perhaps as a founding event, in eukaryotic evolution. Comparative study of different mitochondrial homologues is needed to determine their fundamental importance for contemporary eukaryotic cells.

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“…In eukaryotes, this process takes place exclusively in double membrane-bound organelles including mitochondria (11), hydrogenosomes (12), and chloroplasts (13). Phylogenetic analyses placed the Giardia IscS (GiiscS) within the mitochondrion͞ hydrogenosome clade (10,14). In addition, GiiscS and Giardia scaffold protein (GiiscU) colocalized inside vesicles surrounded by a double membrane and high-speed cellular fractions of Giardia catalyzed reconstitution of FeS clusters in an apoprotein lacking FeS moieties (4).…”

mentioning

confidence: 99%

Giardia mitosomes and trichomonad hydrogenosomes share a common mode of protein targeting

Doležal

Šmíd

Rada

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

138

150

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Mitochondria are archetypal organelles of endosymbiotic origin in eukaryotic cells. Some unicellular eukaryotes (protists) were considered to be primarily amitochondrial organisms that diverged from the eukaryotic lineage before the acquisition of the premitochondrial endosymbiont, but their amitochondrial status was recently challenged by the discovery of mitochondria-like double membrane-bound organelles called mitosomes. Here, we report that proteins targeted into mitosomes of Giardia intestinalis have targeting signals necessary and sufficient to be recognized by the mitosomal protein import machinery. Expression of these mitosomal proteins in Trichomonas vaginalis results in targeting to hydrogenosomes, a hydrogen-producing form of mitochondria. We identify, in Giardia and Trichomonas, proteins related to the component of the translocase in the inner membrane from mitochondria and the processing peptidase. A shared mode of protein targeting supports the hypothesis that mitosomes, hydrogenosomes, and mitochondria represent different forms of the same fundamental organelle having evolved under distinct selection pressures.biogenesis ͉ FeS cluster assembly ͉ Pam18 ͉ matrix-located processing peptidase ͉ ferredoxin

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Phylogenetic affinity of aGiardia lambliacysteine desulfurase conforms to canonical pattern of mitochondrial ancestry

Cited by 24 publications

References 40 publications

Mitochondrial-type assembly of FeS centers in the hydrogenosomes of the amitochondriate eukaryote Trichomonas vaginalis

Mitochondrial-type assembly of FeS centers in the hydrogenosomes of the amitochondriate eukaryote Trichomonas vaginalis

Multiple secondary origins of the anaerobic lifestyle in eukaryotes

Giardia mitosomes and trichomonad hydrogenosomes share a common mode of protein targeting

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