Characterization of the Protein Tyrosine Phosphatase LmPRL-1 Secreted by Leishmania major via the Exosome Pathway

Similar to other intracellular pathogens, parasites are known to evade the antimicrobial effector functions of host immune cells. To date, however, only a few virulence factors have been described for , one of the causative agents of cutaneous leishmaniasis. Here, we have characterized the expression and function of an phosphatase, which we termed LmPRL-1. This enzyme shows a strong structural similarity to the human phosphatases of regenerating liver (PRL-1, -2, and -3) that regulate the proliferation, differentiation, and motility of cells. The biochemical characterization of the phosphatase revealed that the enzyme is redox sensitive. When analyzing the subcellular localization of LmPRL-1 in promastigotes, amastigotes, and infected macrophages, we found that the phosphatase was predominantly expressed and secreted by promastigotes via the exosome route. Finally, we observed that ectopic expression of LmPRL-1 in led to an increased number of parasites in macrophages. From these data, we conclude that the phosphatase LmPRL-1 contributes to the intracellular survival of the parasites in macrophages.