Regulatory volume decrease in Trypanosoma cruzi involves amino acid efflux and changes in intracellular calcium

Peter Rohloff, Claudia D Rodrigues, R. Docampo

Research output: Contribution to journalArticle

86 Citations (Scopus)

Abstract

A regulatory volume decrease (RVD) in response to hyposmotic stress has been characterized in different life-cycle stages of Trypanosoma cruzi. Hyposmotic stress initially caused swelling, but this was rapidly reversed by a compensatory volume reversal that was essentially complete by 5min. Volume recovery was associated with an amino acid efflux that accounted for approximately 50% of the regulatory volume decrease in all three life-cycle stages. The amino acid efflux was selective for neutral and anionic amino acids, but excluded cationic amino acids. Acidocalcisomes contained an amino acid pool over four times more concentrated than whole-cell levels, but about 90% of this was composed of Arg and Lys, so involvement of this pool in amino acid efflux was ruled out. Hyposmotic stress induced a rise in intracellular calcium that was dependent on influx of calcium across the plasma membrane, since chelation of extracellular calcium abolished the response. Influx of calcium was confirmed by demonstration of manganese-mediated quenching of intracellular fura-2 fluorescence and partial inhibition of the rise in calcium by calcium channel blockers. Manipulation of intra- and extracellular calcium levels had minor effects on the initial rate of amino acid efflux and no effect on the rate of volume recovery.

Original languageEnglish
Pages (from-to)219-230
Number of pages12
JournalMolecular and Biochemical Parasitology
Volume126
Issue number2
DOIs
StatePublished - Feb 1 2003
Externally publishedYes

Fingerprint

Trypanosoma cruzi
Calcium
Amino Acids
Life Cycle Stages
Neutral Amino Acids
Fura-2
Calcium Channel Blockers
Manganese
Fluorescence
Cell Membrane

Keywords

  • Acidocalcisome
  • Calcium
  • Regulatory volume decrease
  • Trypanosoma cruzi

ASJC Scopus subject areas

  • Molecular Biology
  • Parasitology

Cite this

Regulatory volume decrease in Trypanosoma cruzi involves amino acid efflux and changes in intracellular calcium. / Rohloff, Peter; Rodrigues, Claudia D; Docampo, R.

In: Molecular and Biochemical Parasitology, Vol. 126, No. 2, 01.02.2003, p. 219-230.

Research output: Contribution to journalArticle

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