Biology subjects

Tachezy, J.

Publications and source records attributed to Tachezy, J..

5 recordsLinked to original sources

bioRxiv2026

The mannose 6-phosphate receptor system is ancient, widespread in eukaryotes, and functionally diversified in the human parasite Trichomonas vaginalis

In mammals, the mannose 6-phosphate (M6P) pathway tags newly synthesized hydrolases for delivery to the lysosomes. The pathway underlies healthy lysosomal function, but whether an equivalent system operates outside animals remains largely unexplored. Surveying 53 representative species, across eukaryotic supergroups we show that the M6P receptor (MPR), the phosphorylating enzyme GNPT, and the uncovering enzyme (UCE) form a statistically robust, co-occurring module across extant eukaryotic supergroups. In the human parasite Trichomonas vaginalis, this module has diversified into an expanded MPR family of seven paralogs, the largest reported within these 53 species, alongside a structurally minimal single GNPT gene, despite the complete absence of UCE. Using co-immunoprecipitation (co-IP), mass spectrometry and confocal microscopy, we demonstrate that MPRs and GNPT localise to the Golgi apparatus, and their interactomes show paralog-specific enrichment of distinct hydrolase cargo, adaptor complexes and the retromer complex proteins for retrieval of MPRs, presenting a full receptor-recycling cycle. Critically, mass spectrometry based glycomics directly detects mature M6P-modified N-glycans in T. vaginalis built on unique Man5GlcNAc2 structure with no trace of GlcNAc-capped intermediate, seen in mammalian cells. Together, these results provide evidence that M6P pathway is an ancient and widespread eukaryotic system, with its functionally diversified variant operating in T. vaginalis for lysosomal biogenesis.

molecular biology↗

bioRxiv2026

Trichomonas vaginalis targets Lactobacillus jensenii via pseudopodia-independent phagocytosis and secreted lysozyme TvGH25

A low abundance or absence of protective lactobacilli during acute trichomoniasis is a well-known phenomenon that is associated with T. vaginalis (TV) infection. However, a crucial question that remains unanswered is whether alterations in the lactobacilli population precede TV infection or whether the parasite plays an active role in lactobacilli disappearance. Our findings showed that TV efficiently phagocytosed one of the dominant Lactobacillus species L. jensenii (LJ). Phagocytosis proceeds via a pseudopodia-independent mechanism reminiscent of sinking with a preference for viable cells. The presence of viable LJ leads to an increase in secretion of 27 TV proteins, including TvGH25 lysozyme. This enzyme cleaves peptidoglycan, a major component of the bacterial cell wall. TV overexpressing TvGH25 effectively lowers the bacterial cell count, evidencing the enzymes antimicrobial potential. These data support the notion that TV cells can suppress the Lactobacillus population through a combination of targeted secretory response and phagocytic activity, revealing novel potential targets for developing alternative therapeutic strategies against trichomoniasis. Significance StatementTrichomonas vaginalis (TV) is a sexually transmitted parasite that causes trichomoniasis and is connected to the disruption of the healthy vaginal microbiome, dominated by Lactobacillus species. However, the nature of the interactions between TV and Lactobacillus is poorly understood. In this study, we show that TV uses an unusual form of pseudopodia-independent phagocytosis to engulf L. jensenii alongside a targeted secretory response to the bacterial encounter, involving TvGH25 lysozyme. We found that TV acquired this enzyme by lateral gene transfer from bacteria and repurposed it against bacteria to degrade the major bacterial cell wall component peptidoglycan. TvGH25 thus represents an effective component of TVs antibacterial arsenal. Our findings provide new insights into the mechanistic disruption of the protective Lactobacillus microbiota.

microbiology↗

bioRxiv2026

The anaerobic fungus Caecomyces churrovis produces H2 via a non-bifurcating NADH-dependent enzyme complex

Hydrogenosomes are mitochondria-derived organelles that produce ATP and H2 to support energy metabolism in anaerobic eukaryotes. H2 production allows reoxidation of reduced cofactors generated during fermentative metabolism; however, the metabolic mechanisms for H2 production in anaerobic eukaryotes remains incompletely understood. In particular, it remains unclear whether anaerobic fungi (AF) hydrogenosomes use a ferredoxin-dependent pathway or a distinct mechanism to regenerate NAD(P)+ and link electron transfer to H2 formation. Here, by combining genomic search, proteomic analysis, and enzymology, we reveal the molecular mechanism for H2 production in the AF strain Caecomyces churrovis. Our enzyme assays on the organelle fraction of C. churrovis revealed the activity of H2:NAD+ oxidoreductase but not pyruvate:ferredoxin oxidoreductase, which is usually linked to H2 formation. We identified genes encoding [FeFe] hydrogenase (Hyd) and NADH dehydrogenase subunits E and F (NuoE, NuoF) in C. churrovis, and confirmed their expression in the isolated hydrogenosomal fractions by proteomic analysis. Combining the individually purified enzymes, we found Hyd and NuoEF proteins formed H2 directly from NADH independently of ferredoxin, functioning as a non-bifurcating NADH-dependent enzyme rather than an electron-bifurcating enzyme. We identified homologs of hydrogenosomal NuoE, NuoF, and Hyd in many other AF, indicating this pathway is commonly shared among the AF. This work demonstrates the existence of a non-bifurcating NADH-dependent enzyme complex in eukaryotes. Moreover, this complex could potentially be exploited as a target for controlling AF H2 production and altering fungal metabolism. IMPORTANCEH2 production is a prominent feature of anaerobic energy metabolism, yet our understanding of eukaryotic mechanisms remains limited. Anaerobic fungi (AF) are key decomposers of lignocellulose and contribute to hydrogen flux in anaerobic environments. Although it has been more than 40 years since the H2 production from AF was first reported, the molecular mechanism for hydrogenosomal H2 production and redox balance remains unclear. We demonstrate that AF produce H2 from NADH utilizing a non-bifurcating NADH-dependent enzyme complex rather than an electron-bifurcating, ferredoxin-dependent variant. We show that this enzyme complex is conserved across multiple AF lineages and thus demonstrate the occurrence of a non-bifurcating NADH-dependent enzyme in eukaryotes. This discovery expands our understanding of eukaryotic hydrogenosomal metabolism, reveals a previously unknown strategy for redox balancing, and highlights potential targets for manipulating H2 production. These insights have broad implications for microbial energy metabolism, anaerobic ecosystems, and bioengineering of H2-producing systems.

microbiology↗

bioRxiv2024

Tracing back the expansion of the endomembrane rescue systems in parasitic Parabasalids to the ancestral origin in its free-living sister lineage

Early Endosomes sort transmembrane cargo whether for lysosomal degradation or retrieval to the plasma membrane or the Golgi complex. Endosomal retrieval in eukaryotes is governed by the anciently homologous Retromer or Retriever complexes. Each comprises a core tri-protein subcomplex, membrane-deformation proteins, and interacting partner complexes, together retrieving a variety of known cargo proteins. Trichomonas vaginalis; a sexually transmitted human parasite uses the endomembrane system for pathogenesis. It has massively and selectively expanded its endomembrane protein complement, the evolutionary path of which has been largely unexplored. Our molecular evolutionary study of Retromer, Retriever and associated machinery in parabasalids and its free-living sister lineage of Anaeramoeba, demonstrates specific expansion of the Retromer machinery, contrasting with the Retriever components. We also observe partial loss of Commander complex and Sorting Nexins in Parabasalia but complete retention in Anaeramoeba. Notably, we identify putative parabasalid Sorting Nexin analogues. Finally, we report the first Retriever protein localization in a non-metazoan group along with Retromer protein localization in T. vaginalis. Therefore, we provide a unique genome expansion study of endomembrane trafficking system in parasitic and free-living protists alike. O_FIG O_LINKSMALLFIG WIDTH=182 HEIGHT=200 SRC="FIGDIR/small/574884v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@1824974org.highwire.dtl.DTLVardef@a46dceorg.highwire.dtl.DTLVardef@1251acborg.highwire.dtl.DTLVardef@1024289_HPS_FORMAT_FIGEXP M_FIG C_FIG

evolutionary biology↗

bioRxiv2021

Anaerobic derivates of mitochondria and peroxisomes in the free-living amoeba Pelomyxa schiedti revealed by single-cell genomics

Pelomyxa schiedti is a free-living amoeba belonging to the group Archamoebae, which encompasses anaerobes bearing mitochondrion-related organelles (MROs) - hydrogenosomes in free-living Mastigamoeba balamuthi and mitosomes in the human pathogen Entamoeba histolytica. Anaerobic peroxisomes, another adaptation to anaerobic lifestyle, were identified only recently in M. balamuthi. We found evidence for both these organelles in the single-cell-derived genome and transcriptome of P. schiedti, and corresponding vesicles were tentatively revealed in electron micrographs. In silico reconstructed MRO metabolism seems similar to that of M. balamuthi harboring respiratory complex II, electron-transferring flavoprotein, partial TCA cycle running presumably in reductive direction, pyruvate:ferredoxin oxidoreductase, [FeFe]-hydrogenases, glycine cleavage system, and sulfate activation pathway. The cell disposes with an expanded set of NIF enzymes for iron sulfur cluster assembly, but their localization remains unclear. Quite contrary, out of 67 predicted peroxisomal enzymes, only four were reported also in M. balamuthi, namely peroxisomal processing peptidase, nudix hydrolase, inositol 2-dehydrogenase, and D-lactate dehydrogenase. Other putative functions of peroxisomes could be pyridoxal 5I-phosphate biosynthesis, amino acid and carbohydrate metabolism, and hydrolase activities. Future experimental evidence is necessary to define functions of this surprisingly enzyme-rich anaerobic peroxisome. Author summaryA major part of the microbial diversity cannot be cultured in isolation, and so it escapes from traditional ways of investigation. In this paper, we demonstrate the successful approach for generating good-quality genome and transcriptome drafts from a peculiar amoeba Pelomyxa schiedti using single-cell methods. P. schiedti is a member of Archamoebae clade harboring microaerobic protists including a free-living Mastigamoeba balamuthi and a human parasite Entamoeba histolytica. Mitochondria and peroxisomes represent two organelles that are most affected during adaptation to microoxic or anoxic environments. Mitochondria are known to transform to anaerobic mitochondria, hydrogenosomes, mitosomes, and various transition stages in between, all of which encompass different enzymatic capacity. Anaerobic peroxisomes have been first noticed in M. balamuthi, but their function remained unclear for now. Data obtained in this study were used for revealing the presence and for the detailed functional annotations of anaerobic derivates of mitochondria and peroxisomes in P. schiedti, which were corroborated by transmission electron microscopy.

evolutionary biology↗