title: Involvement of protein tyrosine kinases and phosphatases in uptake and intracellular replication of virulent and avirulent Leishmania donovani promastigotes in mouse macrophage cells.
abstract: In this study we show that protein tyrosine kinases (PTKs) and also protein tyrosine phosphatases are involved in the uptake of virulent and avirulent Leishmania donovani promastigotes by macrophage cells. Protein tyrosine kinase inhibitors such as genistein or tyrphostin 25 decrease parasite uptake in a dose-dependent manner. Addition of sodium orthovanadate, a protein tyrosine phosphatase inhibitor, prior to infection significantly increases parasite internalization. A similar uptake profile was observed with both virulent and avirulent L. donovani promastigotes. Treatment of macrophages with cytochalasin B, an inhibitor of actin polymerization prevents promastigote uptake, indicating that a tyrosine kinase induced actin polymerization signal may be necessary for the entry of the parasites. In contrast, neither genistein nor tyrphostin significantly reduce intracellular replication of this pathogen or nitric oxide production, suggesting that the PTK-mediated signal is not related to the ultimate virulence mechanism associated with intracellular replication of this pathogen. These data collectively suggest that protein tyrosine kinase mediated entry of L. donovani promastigotes into macrophages is not a virulence-associated event.
authors.affiliation: Biomembrane Division, Infectious Disease Group, Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Jadavpur, Calcutta-700032.
authors.forename: Debjani
authors.initials: D
authors.lastname: Ghosh
authors.forename: Prasanta
authors.initials: P
authors.lastname: Chakraborty
mesh_terms: D000199:Actins / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D003571:Cytochalasin B / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology; D007893:Leishmania donovani / Q000187:drug effects / Q000378:metabolism* / Q000472:pathogenicity*; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000382:microbiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000378:metabolism; D010587:Phagocytosis / Q000187:drug effects; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015398:Signal Transduction; D020032:Tyrphostins / Q000494:pharmacology; D014638:Vanadates / Q000494:pharmacology; D014774:Virulence / Q000502:physiology
chemical_list: D000199:Actins; D004791:Enzyme Inhibitors; D020032:Tyrphostins; C079836:tyrphostin 25; D009569:Nitric Oxide; D003571:Cytochalasin B; D014638:Vanadates; D019833:Genistein; D011505:Protein-Tyrosine Kinases; D017027:Protein Tyrosine Phosphatases