Trans-sialidase stimulates eat me response from epithelial cells.

Epithelial cell invasion by the protozoan parasite Trypanosoma cruzi is enhanced by the presence of an enzyme expressed on its cell surface during the trypomastigote life cycle stage. The enzyme, trans-sialidase (TS), is a member of one of the largest gene families expressed by the parasite and the role of its activity in mediating epithelial cell entry has not hitherto been understood. Here we show that the T. cruzi TS generates an eat me signal which is capable of enabling epithelial cell entry. We have utilized purified, recombinant, active (TcTS) and inactive (TcTS2V0) TS coated onto beads to challenge an epithelial cell line. We find that TS activity acts upon G protein coupled receptors present at the epithelial cell synapse with the coated bead, thereby enhancing cell entry. By so doing, we provide evidence that TS proteins bind glycans, mediate the formation of distinct synaptic domains and promote macropinocytotic uptake of microparticles into a perinuclear compartment in a manner which may emulate entosis.

Membrane traffic and synaptic cross-talk during host cell entry by Trypanosoma cruzi.

It is widely accepted that Trypanosoma cruzi can exploit the natural exocytic response of the host to cell damage, utilizing host cell lysosomes as important effectors. It is, though, increasingly clear that the parasite also exploits endocytic mechanisms which allow for incorporation of plasma membrane into the parasitophorous vacuole. Further, that these endocytic mechanisms are involved in cross-talk with the exocytic machinery, in the recycling of vesicles and in the manipulation of the cytoskeleton. Here we review the mechanisms by which T. cruzi exploits features of the exocytic and endocytic pathways in epithelial and endothelial cells and the evidence for cross-talk between these pathways.

Comparative genomic analysis of human infective Trypanosoma cruzi lineages with the bat-restricted subspecies T. cruzi marinkellei.

BACKGROUND: Trypanosoma cruzi marinkellei is a bat-associated parasite of the subgenus Schizotrypanum and it is regarded as a T. cruzi subspecies. Here we report a draft genome sequence of T. c. marinkellei and comparison with T. c. cruzi. Our aims were to identify unique sequences and genomic features, which may relate to their distinct niches. RESULTS: The T. c. marinkellei genome was found to be ~11% smaller than that of the human-derived parasite T. c. cruzi Sylvio X10. The genome size difference was attributed to copy number variation of coding and non-coding sequences. The sequence divergence in coding regions was ~7.5% between T. c. marinkellei and T. c. cruzi Sylvio X10. A unique acetyltransferase gene was identified in T. c. marinkellei, representing an example of a horizontal gene transfer from eukaryote to eukaryote. Six of eight examined gene families were expanded in T. c. cruzi Sylvio X10. The DGF gene family was expanded in T. c. marinkellei. T. c. cruzi Sylvio X10 contained ~1.5 fold more sequences related to VIPER and L1Tc elements. Experimental infections of mammalian cell lines indicated that T. c. marinkellei has the capacity to invade non-bat cells and undergo intracellular replication. CONCLUSIONS: Several unique sequences were identified in the comparison, including a potential subspecies-specific gene acquisition in T. c. marinkellei. The identified differences reflect the distinct evolutionary trajectories of these parasites and represent targets for functional investigation.

Characterization of Evolutionarily Conserved Trypanosoma cruzi NatC and NatA-N-Terminal Acetyltransferase Complexes.

Protein N-terminal acetylation is a co- and posttranslational modification, conserved among eukaryotes. It determines the functional fate of many proteins including their stability, complex formation, and subcellular localization. N-terminal acetyltransferases (NATs) transfer an acetyl group to the N-termini of proteins, and the major NATs in yeast and humans are NatA, NatB, and NatC. In this study, we characterized the Trypanosoma cruzi (T. cruzi) NatC and NatA protein complexes, each consisting of one catalytic subunit and predicted auxiliary subunits. The proteins were found to be expressed in the three main life cycle stages of the parasite, formed stable complexes in vivo, and partially cosedimented with the ribosome in agreement with a cotranslational function. An in vitro acetylation assay clearly demonstrated that the acetylated substrates of the NatC catalytic subunit from T. cruzi were similar to those of yeast and human NatC, suggesting evolutionary conservation of function. An RNAi knockdown of the Trypanosoma brucei (T. brucei) NatC catalytic subunit indicated that reduced NatC-mediated N-terminal acetylation of target proteins reduces parasite growth.

Genome Sequence of Phytomonas françai, a Cassava (Manihot esculenta) Latex Parasite.

Here, we report the genome sequence of the cassava (Manihot esculenta) latex parasite Phytomonas françai P. françai infection is linked with the yield-loss disease "chochamento de raizes" (empty roots) in the Unha variety of cassava, a disease characterized by poor root development and chlorosis of the leaves.