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 language | English |
|---|---|
| Pages (from-to) | 219-230 |
| Number of pages | 12 |
| Journal | Molecular and Biochemical Parasitology |
| Volume | 126 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 1 2003 |
| Externally published | Yes |
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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 journal › Article
}
TY - JOUR
T1 - Regulatory volume decrease in Trypanosoma cruzi involves amino acid efflux and changes in intracellular calcium
AU - Rohloff, Peter
AU - Rodrigues, Claudia D
AU - Docampo, R.
PY - 2003/2/1
Y1 - 2003/2/1
N2 - 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.
AB - 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.
KW - Acidocalcisome
KW - Calcium
KW - Regulatory volume decrease
KW - Trypanosoma cruzi
UR - http://www.scopus.com/inward/record.url?scp=0037327459&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0037327459&partnerID=8YFLogxK
U2 - 10.1016/S0166-6851(02)00277-3
DO - 10.1016/S0166-6851(02)00277-3
M3 - Article
C2 - 12615321
AN - SCOPUS:0037327459
VL - 126
SP - 219
EP - 230
JO - Molecular and Biochemical Parasitology
JF - Molecular and Biochemical Parasitology
SN - 0166-6851
IS - 2
ER -