A Trichomonas vaginalis Rhomboid Protease and Its Substrate Modulate Parasite Attachment and Cytolysis of Host Cells
Abstract
Trichomonas vaginalis is an extracellular eukaryotic parasite that causes the most common, non-viral sexually transmitted infection worldwide. Although disease burden is high, molecular mechanisms underlying T. vaginalis pathogenesis are poorly understood. Here, we identify a family of putative T. vaginalis rhomboid proteases and demonstrate catalytic activity for two, TvROM1 and TvROM3, using a heterologous cell cleavage assay. The two T. vaginalis intramembrane serine proteases display different subcellular localization and substrate specificities. TvROM1 is a cell surface membrane protein and cleaves atypical model rhomboid protease substrates, whereas TvROM3 appears to localize to the Golgi apparatus and recognizes a typical model substrate. To identify TvROM substrates, we interrogated the T. vaginalis surface proteome using both quantitative proteomic and bioinformatic approaches. Of the nine candidates identified, TVAG_166850 and TVAG_280090 were shown to be cleaved by TvROM1. Comparison of amino acid residues surrounding the predicted cleavage sites of TvROM1 substrates revealed a preference for small amino acids in the predicted transmembrane domain. Over-expression of TvROM1 increased attachment to and cytolysis of host ectocervical cells. Similarly, mutations that block the cleavage of a TvROM1 substrate lead to its accumulation on the cell surface and increased parasite adherence to host cells. Together, these data indicate a role for TvROM1 and its substrate(s) in modulating attachment to and lysis of host cells, which are key processes in T. vaginalis pathogenesis.
Additional Information
© 2015 Riestra et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Received: August 26, 2015; Accepted: October 31, 2015; Published: December 18, 2015. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. This work was supported by National Institutes of Health Grant AI103182 (to PJJ), AI066025 (to SU), and T32GM007445 (to SG). AMR was supported by the HHMI Gilliam Fellowship for Advanced Study. The Proteome Exploration Laboratory (AM, MJS, SH) is supported by the Gordon and Betty Moore Foundation grant GBMF775 and the Beckman Institute. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We thank Frances Mercer and Emma Goodwin for technical assistance and members of the laboratory for helpful comments on the manuscript and useful discussions. Author Contributions:Conceived and designed the experiments: AMR SG SH SU PJJ. Performed the experiments: AMR SG. Analyzed the data: AMR SG MJS SH SU PJJ. Contributed reagents/materials/analysis tools: MJS AM SH.Wrote the paper: AMR PJJ.Attached Files
Published - journal.ppat.1005294.pdf
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Additional details
- PMCID
- PMC4684317
- Eprint ID
- 63398
- Resolver ID
- CaltechAUTHORS:20160105-151730598
- AI103182
- NIH
- AI066025
- NIH
- T32GM007445
- NIH
- Howard Hughes Medical Institute (HHMI)
- GBMF775
- Gordon and Betty Moore Foundation
- Caltech Beckman Institute
- Created
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2016-01-06Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field