title: 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.
authors.affiliation: Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America.
authors.forename: Angelica M
authors.initials: AM
authors.lastname: Riestra
authors.affiliation: Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
authors.forename: Shiv
authors.initials: S
authors.lastname: Gandhi
authors.affiliation: Proteome Exploration Laboratory, Division of Biology and Biological Engineering, Beckman Institute, California Institute of Technology, Pasadena, California, United States of America.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Sweredoski
authors.affiliation: Proteome Exploration Laboratory, Division of Biology and Biological Engineering, Beckman Institute, California Institute of Technology, Pasadena, California, United States of America.
authors.forename: Annie
authors.initials: A
authors.lastname: Moradian
authors.affiliation: Proteome Exploration Laboratory, Division of Biology and Biological Engineering, Beckman Institute, California Institute of Technology, Pasadena, California, United States of America.
authors.forename: Sonja
authors.initials: S
authors.lastname: Hess
authors.affiliation: Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.|Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
authors.forename: Sinisa
authors.initials: S
authors.lastname: Urban
authors.affiliation: Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America.|Molecular Biology Institute and Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America.
authors.forename: Patricia J
authors.initials: PJ
authors.lastname: Johnson
mesh_terms: D005260:Female; D005434:Flow Cytometry; D019084:Fluorescent Antibody Technique, Indirect; D057809:HEK293 Cells; D006790:Host-Parasite Interactions / Q000502:physiology*; D006801:Humans; D016297:Mutagenesis, Site-Directed; D010447:Peptide Hydrolases / Q000378:metabolism; D015800:Protozoan Proteins / Q000378:metabolism*; D014247:Trichomonas Vaginitis / Q000378:metabolism*; D014246:Trichomonas vaginalis / Q000201:enzymology* / Q000472:pathogenicity
chemical_list: D015800:Protozoan Proteins; D010447:Peptide Hydrolases