Reversible association of tetraspanin with Trichomonas vaginalis flagella upon adherence to host cells

Abstract

The parasite Trichomonas vaginalis is the causative agent of trichomoniasis, a prevalent sexuallytransmitted infection. Here, we report the cellular analyses of T. vaginalis tetraspanin 6 (TvTSP6).This family of membrane proteins has been implicated in cell adhesion, migration and proliferationin vertebrates. We observed that TvTSP6 expression is upregulated upon contact with vaginalectocervical cells (VECs) and that parasite strains that are highly adherent to VECs express higherlevels of TvTSP6 mRNA relative to poorly adherent strains. TvTSP6 is localized predominantly onthe flagella of parasites cultured in the absence of host cells; however, adherence of the parasite toVECs initially results in a redistribution of the protein to intracellular vesicles and the plasmamembrane of the main body of the cell. We found that a 16-amino-acid C-terminal intracellular tail of TvTSP6 is necessary and sufficient for flagellar localization and protein redistribution when theparasite is in contact with VECs. Additionally, deletion of the C-terminal tail reduced parasitemigration through Matrigel, a mimic of the extracellular matrix. Together, our data support rolesfor TvTSP6 in parasite migration in the host and sensory reception during infection.