Interaction of Leishmania mexicana promastigotes with the plasminogen-plasmin system

Luisana Avilan, Marina Calcagno, Mariana Figuera, Leticia Lemus, Juan Puig, Ana M. Rodriguez

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Abstract

The binding of human plasminogen and plasmin to the promastigote form of Leishmania mexicana was investigated. L. mexicana was capable to bind both molecules, the binding being inhibited by ε-aminocaproic acid. Scatchard plot analysis revealed a dissociation constant (K(d)) value of 2.4 ± 0.8 μM and 0.9 ± 0.1 x 104 binding sites per cell for plasminogen and a K(d) value of 1.2 ± 0.4 μM and 1.6 ± 0.2 x 105 binding sites per cell for plasmin. C-terminal lysine residues are involved in plasminogen binding to cells, since carboxypeptidase B treatment reduced this binding by 34%. Ligand blotting analysis showed a group of proteins, with molecular masses between 105 and 115 kDa, capable to interact with plasminogen. Zymogram analysis showed that the protease activity acquired by L. mexicana, due to the interaction with either plasminogen or plasmin, comprises an important fraction of the total protease activity at pH 7.7. Plasminogen activation by tissue-type plasminogen activator (t-PA) was enhanced by the presence of L. mexicana promastigotes. These results raise the question whether the interaction of L. mexicana with components of the fibrinolytic system is involved in the virulence of the parasite. (C) 2000 Elsevier Science B.V.

Original languageEnglish (US)
Pages (from-to)183-193
Number of pages11
JournalMolecular and Biochemical Parasitology
Volume110
Issue number2
DOIs
Publication statusPublished - Nov 30 2000

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Keywords

  • Leishmania mexicana
  • Plasmin
  • Plasminogen

ASJC Scopus subject areas

  • Parasitology
  • Molecular Biology

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