Iron and contact with host cells induce expression of adhesins on surface of Trichomonas vaginalis

The proteins AP65, AP51, AP33 and AP23 synthesized by Trichomonas vaginalis organisms in high iron play a role in adherence. Multigene families encode enzymes of the hydrogenosome organelles, which have identity to adhesins. This fact raises questions regarding the compartmentalization of the proteins outside the organelle and about the interactions of adhesins with host cells. Data here demonstrate the presence of the proteins outside the organelle under high-iron conditions. Fluorescence and immuno-cytochemical experiments show that high-iron-grown organisms coexpressed adhesins on the surface and intracellularly in contrast with low-iron parasites. Furthermore, the AP65 epitopes seen by rabbit anti-AP65 serum that blocks adherence and detects surface proteins were identified, and a mAb reacting to those epitopes recognized the trichomonal surface. Two-dimensional electrophoresis and immunoblot of adhesins from surface-labelled parasites provided evidence that all members of the multigene family were co-ordinately expressed and placed on the trichomonal surface. Similar two-dimensional analysis of proteins from purified hydrogenosomes obtained from iodinated trichomonads confirmed the specific surface labelling of proteins. Contact of trichomonads with vaginal epithelial cells increased the amount of surface-expressed adhesins. Moreover, we found a direct relationship between the levels of adherence and amount of adhesins bound to immortalized vaginal and ureter epithelial cells, further reinforcing specific associations. Finally, trichomonads of MR100, a drug-resistant isolate absent in hydrogenosome proteins and adhesins, were non-adherent. Overall, the results confirm an important role for iron and contact in the surface expression of adhesins of T. vaginalis organisms.     

Three dimensional visualization of the Golgi apparatus and endoplasmic reticulum in the subcommissural organ cells with high voltage electron microscopy

Fine structure and stereo-images of the Golgi apparatus and endoplasmic reticulum (ER) in the subcommissural organ (SCO) cells were visualized by the application of zinc-iodide osmium tetroxide (ZIO) impregnation, conventional electron microscopy and high voltage electron microscopy (HVEM). The Golgi apparatus in the SCO cells of rats, gerbils and hamsters consisted of flattened saccules stacked in parallel array. It showed a selective staining toward ZIO mixture and might form a complex network of tubular structures because of the presence of numerous fenestrations in the flattened Golgi saccules. The cytoplasm of the SCO cells in the rat and gerbil was crowded by dilated cisternae of the ER with a few flattened profiles. In the hamster SCO cells, however, the dilated cisternae of the ER were not observed. Flattened cisternae of ER in all species studied showed a positivity for ZIO impregnation and formed a complex tubular network, whereas dilated cisternae of the ER in the rats and gerbils did not show any reactivity. It was thus determined that the observation of thin and thick sections selectively stained with appropriate reagent for defined cellular organelles under conventional electron microscopy and HVEM offered valuable information about three-dimensional organization of the cell. A definite species-specific variation of SCO ultrastructure and cytochemistry was also demonstrated.     

Organization and composition of the striated roots supporting the Golgi apparatus,the so-called parabasal apparatus,in parabasalid flagellates

Summary— In parabasalid flagellates, trichomonads and hypermastigids, the stack of cisternae of the Golgi apparatus are supported by striated roots attached to the basal bodies of flagella forming the so-called parabasal apparatus. Monoclonal antibodies raised for several trichomonad species, Monocercomonas, Trichomonas and Tetratrichomonas, label the parabasal fibre in immunofluorescence or immunogold staining and protein bands in immunoblotting. Several antibodies cross-react between trichomonad species, and one of them labels the homologous parabasal fibre in the hypermastigids: Trichonympha, Joenia, Pseudotrichonympha and Holomastigotoides. Considering the molecular mass range of the labelled proteins (100–135 kDa) and the lack of antibody cross-reactivity with the striated root proteins (centrin, assemblin, kinetodesmal protein, ciliary root proteins of epithelial ciliated cells) of other organisms, these proteins recognized by these antibodies seem to represent a new class of protein forming striated roots. The occurrence and significance of parabasal organization in eukaryogenesis is discussed.     

Fine structural and cytochemical studies on the hamster subcommissural organ

The subcommissural organ (SCO) of the golden hamster (Mesocricetus auratus) was studied by conventional electron microscopy, freeze-fracture technique, zinc-iodide-osmium (ZIO) and acid phosphatase cytochemical reactions. The ultrastructure of hamster SCO cells shows a few flattened cisternae of rough endoplasmic reticulum (ER) without dilated ones in the cytoplasm. The Golgi apparatus is very well developed. Freeze-fracture studies also indicate only short profiles of flattened ER in the cytoplasm endorsing the absence of dilated ER cisternae. After the treatment with ZIO mixture, reaction products were observed over flattened cisternae of the ER and the nuclear envelope. The Golgi apparatus was also reactive toward the ZIO mixture. Acid phosphatase activities are localized in the inner one or two saccules of the Golgi apparatus and dense bodies. From these results we suggest that (1) hamster SCO cells do not accumulate secretory material in the cytoplasm in the form of discrete secretory granules or dilated cisternae of ER, and (2) hamster SCO cells may possess extremely high secretory activity or may not be actively involved in secretory function at all as in rats or other rodents.     

Cytochemical demonstration of NPPase activity for detecting proton-translocating ATPase of Golgi complex in rat pancreatic acinar cells

An attempt at cytochemical demonstration of acidification proton-translocating ATPase (H(+)-ATPase) of Golgi complex in rat pancreatic acinar cells has been made by using p-nitrophenylphosphatase (NPPase) cytochemistry which is used for detecting of Na(+)-K(+)-ATPase (Mayahara et al. 1980) and gastric H(+)-K(+)-ATPase (Fujimoto et al. 1986). K(+)-independent NPPase activity was observed on the membrane of the trans cisternae of Golgi complex, but not inside of cisternae. The localization of NPPase activity is different from that of acid phosphatase activity where reaction products were seen on the inside of the trans Golgi cisternae. Since this activity was insensitive to vanadate, ouabain and independent of potassium ions, it was distinct from plasma membranous ATPases such as Na(+)-K(+)-ATPase and Ca2(+)-ATPase. The K(+)-independent NPPase activity was diminished by the inhibitors of H(+)-ATPase such as N-ethylmaleimide (NEM) and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). The NPPase reaction products were also seen on the membranes of other acidic organelles, i.e., lysosomes, endosomes, autophagosomes and coated vesicles. These results suggest that NPPase activity on the membrane of the Golgi complex and other acidic organelles corresponds with H(+)-ATPase which plays a role in acidification.     

Ultrastructural demonstration of lectin binding sites in the Golgi apparatus of rat epiphyseal chondrocytes

Summary Binding sites for wheat germ agglutinin (WGA), Dolichos biflorus agglutinin (DBA), Ricinus communis I agglutinin (RCA I) and Limax flavus agglutinin (LFA) have been ultrastructurally detected in rat epiphyseal chondrocytes by a post-embedding cytochemical technique using colloidal gold as marker. The four lectins labelled exclusively the Golgi apparatus of chondrocytes embedded in Lowicryl K4M resin by two different methods. WGA binding sites were localized in medial and trans cisternae as well as in immature secretory vesicles, whereas those for DBA were seen concentrated in cis and medial cisternae. Labelling with both RCA I and LFA lectins was distributed throughout all the cisternac of the Golgi stack, and the latter also in vesicles and tubules at the trans face. Neuraminidase pretreatment of the sections abolished LFA staining, decreased reaction with WGA and increased that with RCA I, while it did not affect DBA staining. After chondroitinase ABC treatment only the RCA I reaction was modified, revealing new binding sites in the trans Golgi face, secretory granules and extracellular matrix. These results indicate that the distribution of subcompartments in the Golgi apparatus of chondrocytes is different from that in cells secreting glycoproteins as major products.     

Cytochemical demonstration of NPPase activity for detecting proton-translocating ATPase of Golgi complex in rat pancreatic acinar cells

Summary An attempt at cytochemical demonstration of acidification proton-translocating ATPase (H⁺-ATPase) of Golgi complex in rat pancreatic acinar cells has been made by using p-nitrophenylphosphatase (NPPase) cytochemistry which is used for detecting of Na⁺-K⁺-ATPase (Mayahara et al. 1980) and gastric H⁺-K⁺-ATPase (Fujimoto et al. 1986). K⁺-independent NPPase activity was observed on the membrane of the trans cisternae of Golgi complex, but not inside of cisternae. The localization of NPPase activity is different from that of acid phosphatase activity where reaction products were seen on the inside of the trans Golgi cisternae. Since this activity was insensitive to vanadate, ouabain and independent of potassium ions, it was distinct from plasma membranous ATPases such as Na⁺-K⁺-ATPase and Ca²⁺-ATPase. The K⁺-independent NPPase activity was diminished by the inhibitors of H⁺-ATPase such as N-ethylmaleimide (NEM) and 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS). The NPPase reaction products were also seen on the membranes of other acidic organelles, i.e., lysosomes, endosomes, autophagosomes and coated vesicles. These results suggest that NPPase activity on the membrane of the Golgi complex and other acidic organelles corresponds with H⁺-ATPase which plays a role in acidification.     

Lectin cytochemistry in the gastrointestinal tract with special reference to glycosylation in the Golgi apparatus of Brunner's gland cells.

Two hydrophilic, low temperature-embedding resins, Lowicryl K4M and LR White, were compared in lectin cytochemistry. Post-embedding staining of colloidal gold-labeled Griffonia symplicifolia agglutinin II (GSA-II) resulted in staining of the Golgi apparatus and mucous granules of mucous neck cells in the gastric fundic gland, pylorocytes, and Brunner's gland cells embedded in either resin, although it was much easier to make ultra-thin sections with LR White-embedded material than with the other. Post-fixation with uranyl acetate followed by LR White embedding improved general ultrastructure so that lectin binding sites were identified precisely. All examined lectins, soybean agglutinin (SBA), Maclura pomifera agglutinin (MPA), GSA-II, and Ulex europaeus agglutinin I (UEA-I), stained mucous granules and the Golgi apparatus, in which the staining pattern was characteristic of each lectin: cis cisternae were labeled with SBA and MPA, intermediate cisternae with GSA-II, and trans cisternae and mucous granules with SBA, GSA-II, UEA-I, and lightly with MPA. No labeling was observed in the rough endoplasmic reticulum with any lectin. These findings suggest that the Golgi apparatus is the site of O-linked glycosylation and can be divided into at least three distinct compartments with regard to the glycosylation.     

A role for clathrin in reassembly of the Golgi apparatus

The Golgi apparatus is a highly dynamic organelle whose organization is maintained by a proteinaceous matrix, cytoskeletal components, and inositol phospholipids. In mammalian cells, disassembly of the organelle occurs reversibly at the onset of mitosis and irreversibly during apoptosis. Several pharmacological agents including nocodazole, brefeldin A (BFA), and primary alcohols (1-butanol) induce reversible fragmentation of the Golgi apparatus. To dissect the mechanism of Golgi reassembly, rat NRK and GH3 cells were treated with 1-butanol, BFA, or nocodazole. During washout of 1-butanol, clathrin, a ubiquitous coat protein implicated in vesicle traffic at the trans-Golgi network and plasma membrane, and abundant clathrin coated vesicles were recruited to the region of nascent Golgi cisternae. Knockdown of endogenous clathrin heavy chain showed that the Golgi apparatus failed to reform efficiently after BFA or 1-butanol removal. Instead, upon 1-butanol washout, it maintained a compact, tight morphology. Our results suggest that clathrin is required to reassemble fragmented Golgi elements. In addition, we show that after butanol treatment the Golgi apparatus reforms via an initial compact intermediate structure that is subsequently remodeled into the characteristic interphase lace-like morphology and that reassembly requires clathrin.     

Localization of Mannose, TV-Acetylglucosamine and Galactose in the Golgi Apparatus, Plasma Membranes and Cell Walls of Scenedesmus acuminatus

The localization of lectin binding sites in the Golgi apparatus,plasma membranes and cell walls of Scenedesmus acuminatus wasinvestigated by cytochemical electron microscopy. The lectinsused were concanavalin A (Con A), peanut agglutinin (PNA) andwheat germ agglutinin (WGA), all labeled with gold. Con A-goldparticles were deposited not on the Golgi apparatus, but onthe outer cell-wall layer. PNA-gold and WGA-gold particles weredeposited on distal Golgi cisternae and vesicles derived fromthe Golgi apparatus. Entire cell-wall layers were evenly labeledby PNA-gold. The plasma membrane and cytoplasmic regions closeto the plasma membrane were labeled with WGA-gold. The processingof oligosaccharide in the Golgi apparatus, plasma membranesand cell walls of Scenedesmus acuminatus is discussed in referenceto that reported for animal cells. (Received March 5, 1987; Accepted July 18, 1987)     

Interrelationships between Golgi, GERL and synaptic vesicles in the nerve cells of insect and gastropod ganglia.

In addition to demonstrating synaptic vesicles, staining with the zinc-iodide-osmium tetroxide (ZIO) method reveals the presence of positively reacting GERL membranes in association with the Golgi complex and lysosomes in the nerve cell bodies within ganglia from the locust Schistocerca gregaria and the gastropod molluscs, Limnaea stagnalis and Helix aspersa. A positive response to ZIO occurs in certain Golgi vesicles and saccules, in GERL (Golgi-endoplasmic-reticulum-lysosomes), in multivesicular bodies as well as residual bodies and in small vesicles and cisternae of axonal smooth endoplasmic reticllum (ER). The interrelationships between these organelles are considered in view of the similarity of the ZIO localization to phosphatase-rich sites in the neuronal perikarya and with respect to the possibility that components of the synaptic vesicles are formed in the Golgi region of the cell and migrate via the axonal smooth ER to the synaptic regions.     

Ultrastructural localization of complex carbohydrates in odontoblasts, predentin, and dentin

Glycosaminoglycans (GAGs) and glycoproteins (GPs) are essential components for dentinogenesis. We have examined rat odontoblasts, predentin, and dentin decalcified with EDTA and stained with: 1) Spicer's hig-iron diamine-thiocarbohydrazide-silver proteinate (HID-TCH-SP) method for sulfated glycoconjugates, and 2) Thiéry's periodate-thiocarbohydrazide-silver proteinate (PA-TCH-SP) method for vicinal glycol-containing glycoconjugates. HIS-TCH-SP stained distended portions of Golgi saccules and secretory granules. The predentin contained three times the number of HID-TCH-SP stain precipitates when compared to the mineralization front of the dentin matrix. PA-TCH-SP weakly stained membranes of Golgi saccules and cisternae of rough endoplasmic reticulum (RER), whereas stronger staining was observed in secretory granules, lysosomes, and multivesicular bodies (MVBs). Collagen fibrils in predentin demonstrated moderate PA-TCH-SP staining. In contrast, strong PA-TCH-SP staining was observed on and between collagen fibrils in the mineralization front of the dentin matrix. TCH-SP controls of unosmicated specimens lacked significant staining, however, osmicated control specimens did contain some TCH-SP stain deposits in the mineralization front. These results indicate that sulfated and vicinal glycol-containing glycoconjugates are packaged in the same type of secretory granule and released into the extracellular matrix; subsequently vicinal glycol-containing glycoconjugates concentrate in the calcification front, whereas sulfated glycoconjugates accumulate in the predentin and are either removed or masked to staining in the dentin.     

Early events of secretory granule formation in the rat parotid acinar cell under the influence of isoproterenol. An ultrastructural and lectin cytochemical study

The events involved in the maturation process of acinar secretory granules of rat parotid gland were investigated ultrastructurally and cytochemically by using a battery of four lectins [Triticum vulgaris agglutinin (WGA), Ulex europaeus agglutinin I (UEA-I), Glycine max agglutinin (SBA), Arachys hypogaea agglutinin (PNA)]. In order to facilitate the study, parotid glands were chronically stimulated with isoproterenol to induce secretion. Specimens were embedded in the Lowicryl K4M resin. The trans-Golgi network (TGN) derived secretory granules, which we refer to as immature secretory granules, were found to be intermediate structures in the biogenesis process of the secretory granules in the rat parotid acinar cell. These early structures do not seem to be the immediate precursor of the mature secretory granules: in fact, a subsequent interaction process between these early immature granule forms and TGN elements seems to occur, leading, finally, to the mature granules. These findings could explain the origin of the polymorphic subpopulations of the secretory granules in the normal acinar cells of the rat parotid gland. The lectin staining patterns were characteristic of each lectin. Immature and mature secretory granules were labelled with WGA, SBA, PNA, and lightly with UEA-I. Cis and intermediate cisternae of the Golgi apparatus were labelled with WGA, and trans cisternae with WGA and SBA.     

Golgi apparatus and TGN during endocytosis

Wheat germ agglutinin labelled with horseradish peroxidase (WGA) was used for analyses of endosomal compartments and Golgi apparatus in HepG(2) hepatoma cells during early and late periods of endocytosis. WGA was rapidly transferred into the Golgi region. Transport of internalised WGA into the Golgi apparatus could be classified in three stages. A short stage I, characterised by predominance of vesicular endosomes, was followed by stage II showing new formations of extended endocytic trans Golgi networks (TGNs); the endocytic TGNs comprised reticular and globular parts, showed intimate associations with segments of the endoplasmic reticulum and budding of multiple coated vesicles. Parts of the endocytic TGNs associated with trans Golgi cisternae and became integrated into Golgi stacks. During stage III, concomitantly with integration into the stacks, the endocytic TGNs decreased in size and stacked Golgi cisternae became prominent endocytic compartments. Our results show that endocytosis of WGA is connected with extensive membrane dynamics at the trans Golgi side: an endocytic TGN is newly formed, increases in size and is consumed again. The findings suggest that incorporation of TGN elements into Golgi stacks provides a mechanism for uptake of internalised WGA into the Golgi apparatus.     

Lectin Analysis of Surface Saccharides in Two Trichomonas vaginalis Strains Differing in Pathogenicity*

SYNOPSIS. Surface saccharides in 2 Trichomonas vaginalis strains, the moderately pathogenic, JH34A, and the mild, JH162A, were analyzed with the aid of plant lectins. Concanavalin A (Con A), wheat germ agglutinin (WGA), soybean agglutinin (SBA), castor bean agglutinin (CBA), and lectin from the garden pea (GPA) were employed in agglutination tests and in treatment of ultrathin sections for electron microscopy according to the horseradish peroxidase-3,3′-diaminobenzidine method. With Con A and WGA, small quantitative differences were noted between the 2 strains in the results of agglutination and in the reaction-product deposits observed by electron microscopy. Distribution of the binding sites for the 2 lectins was also somewhat different in the JH34A and JH162A trichomonads. In general, the reactions with the more pathogenic strain were slightly stronger. Although the reactions with SBA and CBA lectins were weaker than those with Con A or WGA, they provided the means for qualitative differentiation between the 2 trichomonad strains. SBA alone agglutinated the JH34A strain and formed demonstrable deposits on the cell surfaces. On the other hand, only CBA reacted with JH162A flagellates. The garden pea lectin failed to bind to the surface of either strain. On the basis of results obtained with the control preparations incubated in the presence of specific inhibitors, it was concluded that both strains had α-methyl-D-mannoside and/or α-methyl-D-mannoside-like as well as N-acetyl-D-glucosamine residues on their surfaces. In addition, JH34A strain had D-lactose-containing residues while JH162A trichomonads had residues with D-galactose. Neither strain appeared to possess residues containing N-acetyl-D-galactosamine.     

Brefeldin A-regulated retrograde transport into the endoplasmic reticulum of internalised wheat germ agglutinin

The effects of the fungal metabolite brefeldin A (BFA) on the endocytic routes of internalised wheat germ agglutinin (WGA) were studied in human HepG2 hepatoma cells, drawing particular attention to the application times in relation to the membrane dynamics occurring at the trans Golgi face during endocytosis. As shown in previous studies, transport of internalised WGA into the Golgi apparatus can be classified in three stages being characterised by predominance of vesicular endosomes (stage I), formation of an extended endocytic trans Golgi network (stage II) and uptake of WGA into the stacked Golgi cisternae (stage III). BFA treatment of the cells led to rapid tubular-reticular transformations of the Golgi stacks. Retrograde transport and further destinations of internalised WGA depended on the time of BFA application. When BFA was administered during stages I or II, WGA was localised within the BFA-induced tubules and networks, but never was found within the endoplasmic reticulum. By contrast, BFA treatment during stage III led to a redistribution of internalised WGA into cisternae of the endoplasmic reticulum. These results show that BFA administered according to a precise time schedule can be used as a regulatory agent that allows to control retrograde traffic of internalised molecules into the endoplasmic reticulum.     

Molecular basis of host epithelial cell recognition by Trichomonas vaginalis

Parasitism of host epithelial cells by Trichomonas vaginalis is a highly specific event. Four trichomonad surface proteins (adhesins) with molecular masses of 65,000 daltons (65 kDa; AP65), 51 kDa (AP51), 33 kDa (AP33), and 23 kDa (AP23) mediate the interaction of T. vaginalis with epithelial cells. Fresh isolates, when compared with long-term-grown isolates, had greater amounts of adhesins, which corresponded with increased levels of cytoadherence. Anti-adhesin antibodies reacted by immunoblot only with the respective protein and detected, by indirect immunofluorescence, each adhesion on the parasite surface. These antibodies inhibited the binding of live parasites to epithelial cells and protected epithelial cells from contact-dependent cytotoxicity. The pretreatment of epithelial cells with a preparation of purified adhesions also blocked trichomonal cytoadherence. Moreover, HeLa cells possessed molecules which recognized and bound to adhesins on nitrocellulose blots.     

Virus in Trichomonas--an ultrastructural study

Trichomonas vaginalis is a flagellated, parasitic protozoan that inhabits the urogenital tract of humans. Approximately one-half of isolates of T. vaginalis are infected with a double-stranded (ds) RNA virus, which was described in the literature as a homogeneous population of icosahedral virus with isometric symmetry and 33 nm in diameter. The present study describes the heterogeneous virus population found in T. vaginalis isolate 347. This population comprises different virus sizes (33-200 nm) and shape (filamentous, cylindrical, and spherical particles). These observations were made in CsCl-purified virus fractions as well as the thin sections of parasites. Some viruses were only observed after slight changes in the technique where the sample was prepared by the negative staining carbon-film method directly onto freshly cleft mica. The VLPs were found in the cytoplasm closely associated with the Golgi complex, with some VLPs budding from the Golgi, and other VLPs were detected adjacent to the plasma membrane. Unidentified cytoplasmic inclusions were observed in the region close to the VLPs and Golgi. These results indicate that T. vaginalis organisms may be infected with different dsRNA viruses simultaneously and suggest that T. vaginalis may be a reservoir for several viruses. We also showed some steps in the route of T. vaginalis virus and some aspects of the cytopathology of this infection. Purified VLPs were transfected to virus-free T. vaginalis isolates. Our results demonstrate that TVV attach and penetrate into trichomonads through endocytic coated pits and are maintained within vacuoles during batch culture for several daily passages. Immediately after virus transfection, many cells were lysed, whereas some intact reminiscent cells were recruited forming large clusters. Virus particles were found outside the cells, and in coated pits, within vacuoles in the cytoplasm, and infrequently within the nucleus. The Golgi complex showed changes in its electron density and in the cisternae structure. In lysed cells, virus particles were clearly seen over the residual membranes.     

A protein phosphatase 1 gamma (PP1γ) of the human protozoan parasite Trichomonas vaginalis is involved in proliferation and cell attachment to the host cell

In this work, evidence for a critical role of Trichomonas vaginalis protein phosphatase 1 gamma (TvPP1γ) 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 TvPP1γ proteins was inhibited by CA. Thirdly, reverse genetic studies confirmed that antisense oligonucleotides targeted to PP1γ but not PP1α or β 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 PP1γ could not be ruled out. Analysis of subcellular distribution of TvPP1γ by cell fractionation and electron microscopy demonstrated the association between TvPP1γ 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 PP1γ -dependent dephosphorylation in the early stages of the host-parasite interaction. Molecular modelling of TvPP1γ showed the conservation of residues critical for maintaining proper folding into the gross structure common to PP1 proteins. Taken together, these results suggest that TvPP1γ could be considered a potential novel drug target for treatment of trichomoniasis.