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. 1996 Nov 1;319(Pt 3):691–697. doi: 10.1042/bj3190691

An amino acid channel activated by hypotonically induced swelling of Leishmania major promastigotes.

L L Vieira 1, E Lafuente 1, F Gamarro 1, Z Cabantchik 1
PMCID: PMC1217844  PMID: 8920968

Abstract

Leishmania promastigotes accumulate amino acids (AAs) by an uphill transport mechanism that is dependent on membrane potential. The accumulated AAs provide the cell with an osmotic reservoir that can be utilized for osmoregulation. Exposure of Leishmania promastigotes to hypotonic media induced a rapid release of AAs that was proportional to the imposed osmotic gradients and independent of the ionic strength or the presence of Cl-, K+, Na+ or Ca2+ in the medium. The hypotonically activated AA release pathway was of relatively low chemical specificity. The solutes released included most of the zwitterionic and anionic AAs, predominantly alanine, hydroxyproline, glycine and glutamic acid, whereas cationic AAs were virtually excluded. AA release was markedly blocked by classical anion transport inhibitors such as the disulphonic stilbene 4,4'-diisothiocyanostilbene-2,2'-disulphonate (DIDS) and its dihydro derivative H2DIDS and others, by restoration of isotonicity or by lowering the temperature (4 degrees C). The temperature profile of AA release showed a low energy of activation (Ea 46 +/- 1.3 (S.E.M.) kJ/mol) in the range 15-30 degrees C and a very high Ea (147 +/- 8 kJ/mol) in the range 4-15 degrees C. Parasites exposed to hypotonic media containing AAs also showed a hypotonically stimulated AA uptake under favourable solute concentration gradients. This uptake was analogous for L- and D-isomers of threonine. After hypotonic exposure, cells underwent a depolarization that was largely prevented by anion transport blockers. On the basis of all these results we propose that after hypotonic stress Leishmania promastigotes restore their internal volume by a regulated release of AAs, which involves activation of channels that allow the passage of both neutral and anionic AAs and possibly other anionic substances.

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Selected References

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  1. Banderali U., Roy G. Anion channels for amino acids in MDCK cells. Am J Physiol. 1992 Dec;263(6 Pt 1):C1200–C1207. doi: 10.1152/ajpcell.1992.263.6.C1200. [DOI] [PubMed] [Google Scholar]
  2. Berrier C., Coulombe A., Szabo I., Zoratti M., Ghazi A. Gadolinium ion inhibits loss of metabolites induced by osmotic shock and large stretch-activated channels in bacteria. Eur J Biochem. 1992 Jun 1;206(2):559–565. doi: 10.1111/j.1432-1033.1992.tb16960.x. [DOI] [PubMed] [Google Scholar]
  3. Blum J. J. Effect of osmolality on 86Rb+ uptake and release by Leishmania donovani. J Cell Physiol. 1992 Jul;152(1):111–117. doi: 10.1002/jcp.1041520115. [DOI] [PubMed] [Google Scholar]
  4. Bonay P., Cohen B. E. Neutral amino acid transport in Leishmania promastigotes. Biochim Biophys Acta. 1983 Jun 10;731(2):222–228. doi: 10.1016/0005-2736(83)90012-3. [DOI] [PubMed] [Google Scholar]
  5. Burg M. B. Molecular basis of osmotic regulation. Am J Physiol. 1995 Jun;268(6 Pt 2):F983–F996. doi: 10.1152/ajprenal.1995.268.6.F983. [DOI] [PubMed] [Google Scholar]
  6. Cabantchik Z. I., Greger R. Chemical probes for anion transporters of mammalian cell membranes. Am J Physiol. 1992 Apr;262(4 Pt 1):C803–C827. doi: 10.1152/ajpcell.1992.262.4.C803. [DOI] [PubMed] [Google Scholar]
  7. Chamberlin M. E., Strange K. Anisosmotic cell volume regulation: a comparative view. Am J Physiol. 1989 Aug;257(2 Pt 1):C159–C173. doi: 10.1152/ajpcell.1989.257.2.C159. [DOI] [PubMed] [Google Scholar]
  8. Cronkite D. L., Pierce S. K. Free amino acids and cell volume regulation in the euryhaline ciliate Paramecium calkinsi. J Exp Zool. 1989 Sep;251(3):275–284. doi: 10.1002/jez.1402510303. [DOI] [PubMed] [Google Scholar]
  9. Dall'Asta V., Rossi P. A., Bussolati O., Gazzola G. C. Regulatory volume decrease of cultured human fibroblasts involves changes in intracellular amino-acid pool. Biochim Biophys Acta. 1994 Jan 13;1220(2):139–145. doi: 10.1016/0167-4889(94)90129-5. [DOI] [PubMed] [Google Scholar]
  10. Darling T. N., Blum J. J. Changes in the shape of Leishmania major promastigotes in response to hexoses, proline, and hypo-osmotic stress. J Protozool. 1990 Jul-Aug;37(4):267–272. doi: 10.1111/j.1550-7408.1990.tb01145.x. [DOI] [PubMed] [Google Scholar]
  11. Darling T. N., Burrows C. M., Blum J. J. Rapid shape change and release of ninhydrin-positive substances by Leishmania major promastigotes in response to hypo-osmotic stress. J Protozool. 1990 Nov-Dec;37(6):493–499. doi: 10.1111/j.1550-7408.1990.tb01254.x. [DOI] [PubMed] [Google Scholar]
  12. Frydman B., de los Santos C., Cannata J. J., Cazzulo J. J. Carbon-13 nuclear magnetic resonance analysis of [1-13C]glucose metabolism in Trypanosoma cruzi. Evidence of the presence of two alanine pools and of two CO2 fixation reactions. Eur J Biochem. 1990 Sep 11;192(2):363–368. doi: 10.1111/j.1432-1033.1990.tb19235.x. [DOI] [PubMed] [Google Scholar]
  13. Handa S., Handa A. K., Hasegawa P. M., Bressan R. A. Proline accumulation and the adaptation of cultured plant cells to water stress. Plant Physiol. 1986 Apr;80(4):938–945. doi: 10.1104/pp.80.4.938. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Handler J. S., Kwon H. M. Regulation of renal cell organic osmolyte transport by tonicity. Am J Physiol. 1993 Dec;265(6 Pt 1):C1449–C1455. doi: 10.1152/ajpcell.1993.265.6.C1449. [DOI] [PubMed] [Google Scholar]
  15. Hoffmann E. K., Dunham P. B. Membrane mechanisms and intracellular signalling in cell volume regulation. Int Rev Cytol. 1995;161:173–262. doi: 10.1016/s0074-7696(08)62498-5. [DOI] [PubMed] [Google Scholar]
  16. Hoffmann E. K., Simonsen L. O. Membrane mechanisms in volume and pH regulation in vertebrate cells. Physiol Rev. 1989 Apr;69(2):315–382. doi: 10.1152/physrev.1989.69.2.315. [DOI] [PubMed] [Google Scholar]
  17. Häussinger D., Lang F., Gerok W. Regulation of cell function by the cellular hydration state. Am J Physiol. 1994 Sep;267(3 Pt 1):E343–E355. doi: 10.1152/ajpendo.1994.267.3.E343. [DOI] [PubMed] [Google Scholar]
  18. Kirk K., Ellory J. C., Young J. D. Transport of organic substrates via a volume-activated channel. J Biol Chem. 1992 Nov 25;267(33):23475–23478. [PubMed] [Google Scholar]
  19. Kirk K., Kirk J. Volume-regulatory taurine release from a human lung cancer cell line. Evidence for amino acid transport via a volume-activated chloride channel. FEBS Lett. 1993 Dec 20;336(1):153–158. doi: 10.1016/0014-5793(93)81630-i. [DOI] [PubMed] [Google Scholar]
  20. Knodler L. A., Edwards M. R., Schofield P. J. The intracellular amino acid pools of Giardia intestinalis, Trichomonas vaginalis, and Crithidia luciliae. Exp Parasitol. 1994 Sep;79(2):117–125. doi: 10.1006/expr.1994.1071. [DOI] [PubMed] [Google Scholar]
  21. Law R. O. Regulation of mammalian brain cell volume. J Exp Zool. 1994 Feb 1;268(2):90–96. doi: 10.1002/jez.1402680204. [DOI] [PubMed] [Google Scholar]
  22. McCoy D. E., Guggino S. E., Stanton B. A. The renal cGMP-gated cation channel: its molecular structure and physiological role. Kidney Int. 1995 Oct;48(4):1125–1133. doi: 10.1038/ki.1995.396. [DOI] [PubMed] [Google Scholar]
  23. Roy G., Malo C. Activation of amino acid diffusion by a volume increase in cultured kidney (MDCK) cells. J Membr Biol. 1992 Oct;130(1):83–90. doi: 10.1007/BF00233740. [DOI] [PubMed] [Google Scholar]
  24. Roy G., Sauvé R. Effect of anisotonic media on volume, ion and amino-acid content and membrane potential of kidney cells (MDCK) in culture. J Membr Biol. 1987;100(1):83–96. doi: 10.1007/BF02209143. [DOI] [PubMed] [Google Scholar]
  25. Sarkadi B., Attisano L., Grinstein S., Buchwald M., Rothstein A. Volume regulation of Chinese hamster ovary cells in anisoosmotic media. Biochim Biophys Acta. 1984 Jul 25;774(2):159–168. doi: 10.1016/0005-2736(84)90287-6. [DOI] [PubMed] [Google Scholar]
  26. Sarkadi B., Parker J. C. Activation of ion transport pathways by changes in cell volume. Biochim Biophys Acta. 1991 Dec 12;1071(4):407–427. doi: 10.1016/0304-4157(91)90005-h. [DOI] [PubMed] [Google Scholar]
  27. Schlein Y., Warburg A. Phytophagy and the feeding cycle of Phlebotomus papatasi (Diptera: Psychodidae) under experimental conditions. J Med Entomol. 1986 Jan 24;23(1):11–15. doi: 10.1093/jmedent/23.1.11. [DOI] [PubMed] [Google Scholar]
  28. Strange K., Jackson P. S. Swelling-activated organic osmolyte efflux: a new role for anion channels. Kidney Int. 1995 Oct;48(4):994–1003. doi: 10.1038/ki.1995.381. [DOI] [PubMed] [Google Scholar]
  29. Vieira L. L., Cabantchik Z. I. Amino acid uptake and intracellular accumulation in Leishmania major promastigotes are largely determined by an H(+)-pump generated membrane potential. Mol Biochem Parasitol. 1995 Dec;75(1):15–23. doi: 10.1016/0166-6851(95)02505-7. [DOI] [PubMed] [Google Scholar]
  30. Vieira L., Lavan A., Dagger F., Cabantchik Z. I. The role of anions in pH regulation of Leishmania major promastigotes. J Biol Chem. 1994 Jun 10;269(23):16254–16259. [PubMed] [Google Scholar]
  31. Vieira L., Slotki I., Cabantchik Z. I. Chloride conductive pathways which support electrogenic H+ pumping by Leishmania major promastigotes. J Biol Chem. 1995 Mar 10;270(10):5299–5304. doi: 10.1074/jbc.270.10.5299. [DOI] [PubMed] [Google Scholar]
  32. Zilberstein D., Philosoph H., Gepstein A. Maintenance of cytoplasmic pH and proton motive force in promastigotes of Leishmania donovani. Mol Biochem Parasitol. 1989 Sep;36(2):109–117. doi: 10.1016/0166-6851(89)90183-7. [DOI] [PubMed] [Google Scholar]

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