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Protein kinase A activity is associated with metacyclogenesis in Leishmania amazonensis

Marcelo Genestra1, Léa Cysne-Finkelstein, Leonor Leon

  • 1Department of Immunology, Oswaldo Cruz Institute, 21045-900 Rio de Janeiro, RJ, Brazil. genestra@ioc.fiocruz.br

Cell Biochemistry and Function
|September 1, 2004
PubMed

Insights

Protein kinase A (PKA) activity in Leishmania amazonensis is higher in infective promastigotes, suggesting a role in metacyclogenesis. This PKA may be a target for new leishmanicidal drugs.

Area of Science:

  • Parasitology
  • Molecular Biology
  • Biochemistry

Background:

  • Cell signaling pathways, including adenylate cyclase/protein kinase A (PKA), are crucial for parasite proliferation and differentiation.
  • Leishmania amazonensis, a protozoan parasite, relies on complex signaling for its life cycle stages.

Purpose of the Study:

  • To investigate the role and activity of protein kinase A (PKA) in different life cycle stages of Leishmania amazonensis.
  • To explore the potential of PKA as a drug target for leishmaniasis.

Main Methods:

  • Assaying PKA activity in soluble (SF) and membrane fractions (MF) of promastigotes and axenic amastigotes.
  • Chromatographic purification of PKA using DEAE-cellulose columns.
  • Evaluating phosphorylative activity using [gamma(32)P]-ATP in the presence of cyclic adenosine monophosphate (cAMP) and a PKA inhibitor.

Main Results:

  • PKA activity was significantly higher (approximately twofold) in SF from infective promastigotes (metacyclic forms) compared to non-infective promastigotes.
  • A lower level of phosphorylative activity was detected in axenic amastigotes.
  • The findings suggest a correlation between PKA activity and the metacyclogenesis process.

Conclusions:

  • PKA activity is associated with the metacyclogenesis stage in Leishmania amazonensis.
  • The adenylate cyclase/cAMP pathway, and specifically PKA, may play a role in parasite-host interactions.
  • Leishmania amazonensis PKA represents a potential intracellular target for the development of novel leishmanicidal drugs.

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