All Trypanosoma cruzi developmental forms present lysosome-related organelles

Histochem Cell Biol. 2008 Dec;130(6):1187-98. doi: 10.1007/s00418-008-0486-8. Epub 2008 Aug 12.

Abstract

Trypanosoma cruzi epimastigote forms concentrate their major protease, cruzipain, in the same compartment where these parasites store macromolecules obtained from medium and for this ability these organelles were named as reservosomes. Intracellular digestion occurs mainly inside reservosomes and seems to be modulated by cruzipain and its natural inhibitor chagasin that also concentrates in reservosomes. T. cruzi mammalian forms, trypomastigotes and amastigotes, are unable to capture macromolecules by endocytosis, but also express cruzipain and chagasin, whose role in infectivity has been described. In this paper, we demonstrate that trypomastigotes and amastigotes also concentrate cruzipain, chagasin as well as serine carboxypeptidase in hydrolase-rich compartments of acidic nature. The presence of P-type proton ATPase indicates that this compartment is acidified by the same enzyme as epimastigote endocytic compartments. Electron microscopy analyzes showed that these organelles are placed at the posterior region of the parasite body, are single membrane bound and possess an electron-dense matrix with electronlucent inclusions. Three-dimensional reconstruction showed that these compartments have different size and shape in trypomastigotes and amastigotes. Based on these evidences, we suggest that all T. cruzi developmental stages present lysosome-related organelles that in epimastigotes have the additional and unique ability of storing cargo.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carboxypeptidases / analysis
  • Cysteine Endopeptidases / analysis
  • Image Processing, Computer-Assisted
  • Imaging, Three-Dimensional
  • Life Cycle Stages
  • Lysosomes / enzymology
  • Lysosomes / ultrastructure*
  • Microscopy, Electron, Transmission
  • Organelles / enzymology
  • Organelles / ultrastructure*
  • Proton-Translocating ATPases / analysis
  • Protozoan Proteins / analysis
  • Trypanosoma cruzi / enzymology
  • Trypanosoma cruzi / growth & development
  • Trypanosoma cruzi / ultrastructure*

Substances

  • Protozoan Proteins
  • chagasin, Trypanosoma
  • Carboxypeptidases
  • serine carboxypeptidase
  • Cysteine Endopeptidases
  • cruzipain
  • Proton-Translocating ATPases