Chagas disease is a tropical neglected disease endemic in Latin America and it is caused by the protozoan Trypanosoma cruzi. The parasite has four major life stages: epimastigote, metacyclic trypomastigote, bloodstream trypomastigote and amastigote. The differentiation from infective trypomastigotes into replicative amastigotes, called amastigogenesis, takes place in vivo inside mammalian host-cells after a period of incubation in an acidic phagolysosome. This differentiation process can be mimicked in vitro by incubating tissue culture-derived trypomastigotes in acidic DMEM. Here we use this well-established differentiation protocol to perform a comprehensive quantitative proteomic and phosphoproteomic analysis of the T. cruzi amastigogenesis. Samples from fully differentiated forms and two biologically relevant intermediate time points were Lys-C/trypsin digested, iTRAQ-labeled and multiplexed. Subsequently, phosphopeptides were enriched using TiO2 matrix. Non-phosphorylated peptides were HILIC-fractionated prior to LC-MS/MS analysis. LC-MS/MS and bioinformatics procedures were used for protein and phosphopeptide quantitation, identification and phosphorylation site assignment. We could identify regulated proteins and pathways involved in coordinating amastigogenesis. We could also observe that a significant proportion of the regulated proteins are membrane proteins. Modulated phosphorylation events coordinated by protein kinases and phosphatases that are part of the signaling cascade induced by incubation in acidic medium were also evinced. To our knowledge, this work is the most comprehensive quantitative proteomics study of the T. cruzi amastigogenesis and this data will provide trustworthy basis for future studies and possibly for new potential drug targets.
Molecular and Cellular Proteomics, 2014, Vol 13, Issue 12, p. 3457-3472