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Phosphoproteome dynamics reveal heat-shock protein complexes specific to the Leishmania donovani infectious stage
Miguel A. Morales, Reiko Watanabe, Mariko Dacher, Philippe Chafey, José Osorio y Fortéa, David A. Scott, Stephen M. Beverley, Gabi Ommen, Joachim Clos, Sonia Hem, Pascal Lenormand, Jean-Claude Rousselle, Abdelkader Namane, Gerald F. Späth and Elizabeth Anne Craig
Proceedings of the National Academy of Sciences of the United States of America
Vol. 107, No. 18 (May 4, 2010), pp. 8381-8386
Published by: National Academy of Sciences
Stable URL: http://www.jstor.org/stable/25665547
Page Count: 6
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Leishmania is exposed to a sudden increase in environmental temperature during the infectious cycle that triggers stage differentiation and adapts the parasite phenotype to intracellular survival in the mammalian host. The absence of classical promoter-dependent mechanisms of gene regulation and constitutive expression of most of the heat-shock proteins (HSPs) in these human pathogens raise important unresolved questions as to regulation of the heat-shock response and stage-specific functions of Leishmania HSPs. Here we used a gel-based quantitative approach to assess the Leishmania donovani phosphoproteome and revealed that 38% of the proteins showed significant stage-specific differences, with a strong focus of amastigote-specific phosphoproteins on chaperone function. We identified STI1/HOP-containing chaperone complexes that interact with ribosomal client proteins in an amastigote-specific manner. Genetic analysis of STI1/HOP phosphorylation sites in conditional sti1 -/- null mutant parasites revealed two phosphoserine residues essential for parasite viability. Phosphorylation of the major Leishmania chaperones at the pathogenic stage suggests that these proteins may be promising drug targets via inhibition of their respective protein kinases.
Proceedings of the National Academy of Sciences of the United States of America © 2010 National Academy of Sciences