Dok proteins are recruited to the phagosome and degraded in a GP63-dependent manner during Leishmania major infection |
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Affiliation: | 1. Institute of Nutrition and Functional Foods (INAF), Canada;2. Department of Food Sciences, 2425 rue de l''Agriculture, Laval University, Quebec G1V 0A6, Canada;3. Food Research and Development Centre, Agriculture and Agri-food Canada, 3600 Casavant W., Saint-Hyacinthe, Qc J2S 8E3, Canada;4. Coopérative Agropur, 4700 rue Armand Frappier, St-Hubert, Qc J3Z 1G5, Canada |
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Abstract: | Three adaptor molecules of the Dok family, Dok-1, Dok-2 and Dok-3 are expressed in macrophages and are involved in the negative regulation of signaling in response to lipopolysaccharide and various cytokines and growth factors. We investigated the role and the fate of these proteins following infection with Leishmania major promastigotes in macrophages. The protozoan parasite L. major causes cutaneous leishmaniasis and is known for its capacity to alter host-cell signaling and function. Dok-1/Dok-2−/− bone marrow-derived macrophages displayed normal uptake of L. major promastigotes. Following Leishmania infection, Dok-1 was barely detectable by confocal microscopy. By contrast, phagocytosis of latex beads or zymosan led to the recruitment of Dok-1 to phagosomes. In the absence of the Leishmania pathogenesis-associated metalloprotease GP63, Dok-1 was also, partially, recruited to phagosomes containing L. major promastigotes. Further biochemical analyses revealed that similar to Dok-1, Dok-2 and Dok-3 were targets of GP63. Moreover, we showed that upon infection with wild-type or Δgp63 L. major promastigotes, production of nitric oxide and tumor necrosis factor by interferon-γ-primed Dok-1/Dok-2−/− macrophages was reduced compared to WT macrophages. These results suggest that Dok proteins may be important regulators of macrophage responses to Leishmania infection. |
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Keywords: | Leishmania Metalloprotease GP63 Dok proteins Macrophage Phagosome |
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