Localisation of a family of complex-forming β-barrels in the T. vaginalis hydrogenosomal membrane

Crucial to organellogenesis was the development of membrane translocases responsible for delivering proteins to new cellular compartments. This investigation examines the Trichomonas vaginalis hydrogenosome, a mitochondrially derived organelle. We identify an expanded family of putative β-barrel proteins (THOM A–I) comprising nine related sequences. Sub-cellular localisation by immunofluorescence and biochemical fractionation is consistent with THOMs being localised to the hydrogenosomal membrane. Native gel electrophoresis and chemical cross-linking support the ability of THOM proteins to be components of membrane-bound oligomeric protein complexes, consistent with a role in protein translocation.

► Trichomonas has an expanded family of Tom40-like proteins. ► Tom40 candidates are visualised under confocal microscopy to hydrogenosomal membranes. ► Molecular biology approaches localise recombinant protein to hydrogenosomal membranes. ► Tom40 homologues form complexes in membranes.