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Import of proteins to hydrogenosomes
Import of proteins to hydrogenosomes
We have showed that common principles govern the import of proteins into hydrogenosomes, mitosomes and mitochondria. However, remarkable differences have been observed both in the hydrogenosomal protein import machinery as well as in the targeting signals of hydrogenosomal proteins.
We have showed that common principles govern the import of proteins into hydrogenosomes, mitosomes and mitochondria. However, remarkable differences have been observed both in the hydrogenosomal protein import machinery as well as in the targeting signals of hydrogenosomal proteins.
TOM complex in Trichomonas vaginalis
The translocase of the outer membrane (TOM) is responsible for the import of most proteins into the organelle. Recently, we characterized the TOM complex in T. vaginalis hydrogenosomes. Our studies have shown that TvTOM complex is highly divergent consisting of two modified core subunits – channel-forming TvTom40 isoforms and a Tom22-like protein, and two lineage-specific subunits – Tom36 and Tom46 that most likely function as receptors. Additionally, TvTOM forms a stable supercomplex with Sam50 for a more efficient biogenesis of β-barrel proteins. Electron microscopy revealed that the translocase has a triplet-pore structure with a unique skull shape. The protein import into hydrogenosomes is rather divergent compared to that of mitochondria. The triplet-pore TOM complex composed of conserved core subunits was present in the last common eukaryotic ancestor while the peripheral receptors evolved independently in different eukaryotic lineages.
Electron microscopy of TvTOM complexes: Class averages of TvTOM complexes (A) TvTOM with 1 pore, 70 × 125 Å, (B) TvTOM with 2 pores, 140 × 100 Å and (C) TvTOM with 3 pores, 150 × 175 Å. Arrow indicate additional unknown component that has not been observed in yeast TOMs.
Key Publications:
Doležal et al., 2005, PNAS
Rada et al., 2011, PLoS One
Rada et al., 2015, Euk. Cell
Garg et al., 2015, Genome Biol. Evol.
Makki et al., 2019, PLoS Biology
Makki et al., 2024, BMC Biology
C-tail anchored proteins
C-tail anchored proteins
In this study we investigated the topology of seven representative Trichomonas vaginalis C-tail anchored (TA) proteins in the outer hydrogenosomal membrane and characterized targeting signals that are decisive for their targeting to the hydrogenosome or endoplasmic reticulum (ER) (TAPDI, tail anchored protein disulfide isomerase). Elimination of positive charge in C-terminal domain of CTA4 resulted in major changes in morfology of ER.
Key Publications:
Rada et al., 2011 PLoS One
Rada et al., 2019 Mol. Microbiol.
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