Giardia Mitosomes

intestinalis Cpn60 did not affect the targeting of the protein to mito- 

The targeting information on mitosomal proteins can be recognized and processed by the heterologous systems of human and yeast mitochondria, as well as T. vaginalis hydrogenosomes (Dolezal et al. 2005 Regoes et al. 

---

A high-speed differential centrifugal fraction for Giardia mitosomes has been generated that has been successfully used to reconstitute Fe-S cluster... 

Dolezal P, Smid O, Rada P, Zubacova Z, Bursae D, Sut ak R, Nebesarova J, Lithgow T, Tachezy J (2005) Giardia mitosomes and trichomonad hydrogenosomes share a common mode of protein targeting. Proc Natl Acad Sci USA 102 10924-10929... 

It has recently been reported that Giardia mitosomes, Trichomonas hydrogenosomes and mitochondria share a similar mode of protein targeting and translocation (Dolezal et al. 2005 Regoes et al. 2005). The import of Giardia IscU and ferredoxin into the organelle was shown to be dependent on... 

In anaerobic eukaryotes that perform all of their ATP synthesis in the cytosol, like Entamoeba or Giardia, both of which have mitosomes (Tovar et al. 1999, 2003 Mai et al. 1999), several of the enzymes otherwise found in mitochondria or hydrogenosomes, for example PFO and [Fe]-HYD (Muller 2003)... 

Fig. 2 Mitosomes of Giardia intestinalis localized between axonemes (a) of caudal flagella close to basal bodies (w, nucleus). Scale bar = 500 nm. Kindly provided by E. Noh)mkova, Charles University in Prague, Czech Republic...

A characterization of the translocase complexes responsible for mitosomal protein import in Giardia is under way. An iterative BLAST search of the G. intestinalis genome was employed for the identification of the import machinery components. The only candidate to have been found so far is GiPAMIS, a mitosomal protein homologous to mitochondrial presequence translocase-associated motor 18 (Dolezal et al. 2005). 

Fig. 4 Immunofluorescence microscopy of Giardia intestinalis showing segregation of mi-tosomes during mitosis. A Interphase, prophase, and C telophase cells. Nuclei were stained by DAPI (blue), mitosomes were detected by an antibody raised against GiiscU (red), and axonemes were visualized by the antibody AXO 49 recognizing polyglycylated carboxy-terminal peptides of a- and fl-tubulin (green). Note the proximity of mitosomes (white arrows) to axonemes...

In addition to Giardia, it is likely that mitosomes are present in other related diplomonads, such as the fish parasite Spironucleus. A recent genomic survey of this organism indicated the presence of IscS in this parasite, which might be localized in putative mitosomes (Andersson et al. 2007). However,... 

---