Genome‐wide approaches to dissecting Leishmania differentiation (232.4)

Abstract

Leishmania donovani are intracellular parasitic protozoa that cause visceral leishmaniasis in humans. During their lifecycle these organisms cycle between the midgut of female sand flies, where they reside as extracellular flagellated promastigotes, and the phagolysosomes of macrophages, where they live as aflagellated amastigotes. Promastigote‐to‐amastigote differentiation can be induced in axenic parasites by exposure to the high temperature and acidity (37°C, pH5.5, 5% CO2) typically found in the phagolysosome. Analyses using high‐coverage transcriptomic and proteomic approaches showed that L. donovani differentiation is well‐regulated, with ordered and coordinated changes in mRNA and protein abundance that result in the parasites retooling their metabolic pathways for life in the new environment. We recently described stage‐specific protein phosphorylation patterns, and have now completed an extensive examination of phosphorylation changes during differentiation. In addition to identifying global changes in protein translation between promastigotes and amastigotes, we are now using the new technology of ribosome profiling to identify gene‐specific changes in translation efficiency between the lifecycle stages. The results of these analyses have begun to reveal the molecular basis of differentiation, including a role for protein kinase A (PKA) in its regulation.