文摘
In this work, evidence for a critical role of Trichomonas vaginalis protein phosphatase 1 gamma (TvPP1¦Ã) in proliferation and attachment of the parasite to the mammalian cell is provided. Firstly, proliferation and attachment of T. vaginalis parasites to HeLa cells was blocked by calyculin A (CA), a potent PP1 inhibitor. Secondly, it was demonstrated that the enzyme activity of native and recombinant TvPP1¦Ã proteins was inhibited by CA. Thirdly, reverse genetic studies confirmed that antisense oligonucleotides targeted to PP1¦Ã but not PP1¦Á or ¦Â inhibited proliferation and attachment of trichomonads CA-treated parasites underwent cytoskeletal modifications, including a lack of axostyle typical labelling, suggesting that cytoskeletal phosphorylation could be regulated by a CA-sensitive phosphatase where the role of PP1¦Ã could not be ruled out. Analysis of subcellular distribution of TvPP1¦Ã by cell fractionation and electron microscopy demonstrated the association between TvPP1¦Ã and the cytoskeleton. The expression of adhesins, AP120 and AP65, at the cell surface was also inhibited by CA. The concomitant inhibition of expression of adhesins and changes in the cytoskeleton in CA-treated parasites suggest a specific role for PP1¦Ã -dependent dephosphorylation in the early stages of the host-parasite interaction. Molecular modelling of TvPP1¦Ã showed the conservation of residues critical for maintaining proper folding into the gross structure common to PP1 proteins. Taken together, these results suggest that TvPP1¦Ã could be considered a potential novel drug target for treatment of trichomoniasis.
