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

Rohloff, Peter; Rodrigues, Cláudia O.; Docampo, Roberto

doi:10.1016/s0166-6851(02)00277-3

Cited by 131 publications

(148 citation statements)

References 44 publications

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“…Cell Volume Measurements-Relative changes in cell volume after induction of hypo-osmotic stress were followed by using a light scattering technique as described previously (5,6).…”

Section: Methodsmentioning

confidence: 99%

“…Vacuolar-type (bafilomycin A 1 -sensitive) H ϩ -ATPase was assayed as described previously (14). Aliquots were also assayed for amino acid, P i , and polyP content as described previously (5,17).…”

Section: Methodsmentioning

confidence: 99%

“…Membrane Integrity and Amino Acid Release-Membrane integrity after treatment with AgNO 3 and HgCl 2 was determined by ethidium bromide exclusion as described before (5). Total amino acid content and amino acid analysis of the supernatants of cells exposed to hypotonic or isotonic buffer were determined as described before (5).…”

Section: Methodsmentioning

confidence: 99%

“…Approximately 50% of this compensatory volume reversal could be accounted for by the efflux of cytosolic amino acids (5). Subsequent studies of other major osmolytes, such as sodium, potassium, chloride, inositol, methylamines, P i , and pyrophosphate (PP i ), failed to reveal another efflux mechanism that could account for the remaining volume reversal, except for K ϩ release that could account for only about 7% of the RVD (6).…”

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confidence: 99%

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Acidocalcisomes and the Contractile Vacuole Complex Are Involved in Osmoregulation in Trypanosoma cruzi

Rohloff¹,

Montalvetti²,

Docampo

2004

Journal of Biological Chemistry

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113

149

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Trypanosoma cruzi, the etiologic agent of Chagas disease, resists extreme fluctuations in osmolarity during its life cycle. T. cruzi possesses a robust regulatory volume decrease mechanism that completely reverses cell swelling when submitted to hypo-osmotic stress. The efflux of amino acids and K ؉ release could account for only part for this volume reversal. In this work we demonstrate that swelling of acidocalcisomes mediated by an aquaporin and microtubule-and cyclic AMP-mediated fusion of acidocalcisomes to the contractile vacuole complex with translocation of this aquaporin and the resulting water movement are responsible for the volume reversal not accounted for by efflux of osmolytes. Contractile vacuole bladders were isolated by subcellular fractionation in iodixanol gradients, showed a high concentration of basic amino acids and inorganic phosphate, and were able to transport protons in the presence of ATP or pyrophosphate. Taken together, these results strongly support a role for acidocalcisomes and the contractile vacuole complex in osmoregulation and identify a functional role for aquaporin in protozoal osmoregulation.

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“…Cell Volume Measurements-Relative changes in cell volume after induction of hypo-osmotic stress were followed by using a light scattering technique as described previously (5,6).…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Acidocalcisomes and the Contractile Vacuole Complex Are Involved in Osmoregulation in Trypanosoma cruzi

Rohloff¹,

Montalvetti²,

Docampo

2004

Journal of Biological Chemistry

Self Cite

113

149

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show abstract

“…This compartment, initially named the acidocalcisome in T. brucei, was shown to be implicated in storage of cations and phosphate (7), regulation of intracellular pH (8,9), and osmoregulation (10,11). To better understand the relation between polyP metabolism and its cellular role, studies were performed on the polyP composition and on the characterization of enzymes involved in the metabolism of these compounds.…”

mentioning

confidence: 99%

A Pyrophosphatase Regulating Polyphosphate Metabolism in Acidocalcisomes Is Essential for Trypanosoma brucei Virulence in Mice

Lemercier

Espiau

Ruiz

et al. 2004

Journal of Biological Chemistry

119

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Electrophysiological characterization of potassium conductive pathways in Trypanosoma cruzi

Jiménez

Henríquez

Galanti

et al. 2011

J of Cellular Biochemistry

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Potassium channels (K(+) channels) are members of one of the largest and most diverse families of membrane proteins, widely described from bacteria to humans. Their functions include voltage-membrane potential maintenance, pH and cell volume regulation, excitability, organogenesis and cell death. K(+) channels are involved in sensing and responding to environmental changes such as acidification, O(2) pressure, osmolarity, and ionic concentration. Trypanosoma cruzi is a parasitic protozoan, causative agent of Chagas disease (American trypanosomiasis) an endemic pathology in Latin America, where up 200,000 new cases are reported annually. In protozoan parasites, the presence of K(+) channels has been suggested, but functional direct evidence supporting this hypothesis is limited, mainly due to the difficulty of employing conventional electrophysiological methods to intact parasites. In T. cruzi, K(+) conductive pathways are thought to contribute in the regulatory volume decrease observed under hypoosmotic stress, the steady state pH and the compensatory response to extracellular acidification and the maintenance of plasma membrane potential. In this work we describe the isolation of plasma membrane enriched fractions from T. cruzi epimastigotes, their reconstitution into giant liposomes and the first functional characterization by patch-clamp of K(+) conductive pathways in protozoan parasites.

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

Cited by 131 publications

References 44 publications

Acidocalcisomes and the Contractile Vacuole Complex Are Involved in Osmoregulation in Trypanosoma cruzi

Acidocalcisomes and the Contractile Vacuole Complex Are Involved in Osmoregulation in Trypanosoma cruzi

A Pyrophosphatase Regulating Polyphosphate Metabolism in Acidocalcisomes Is Essential for Trypanosoma brucei Virulence in Mice

Electrophysiological characterization of potassium conductive pathways in Trypanosoma cruzi

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