Intracellular Ca2+ homeostasis in trypomastigotes of Trypanosoma cruzi

Hong Shan Zhang, Thomas V. McDonald, Herbert B. Tanowitz, Murray Wittner, Louis M. Weiss, John P. Bilezikian, Stephen A. Morris

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Trypomastigotes of Trypanosoma cruzi maintain an intracellular Ca2+ concentration([Ca2+](i)) of 64 ± 30 nM. Equilibration of trypomastigotes in an extracellular buffer containing 0.5 mM [Ca2+]0 (preloaded cells) increased [Ca2+](i) < 20 nM whereas total cell Ca2+ increased by 1.5 to 2.0 pmole/cell. This amount of Ca2+ would be expected to increase [Ca2+](i) to > 10 μM suggesting active sequestration of Ca2+. We tested the hypothesis that maintenance of [Ca2+](i) involved both the sequestration into intracellular storage sites and extrusion into the extracellular space. Pharmacological probes known to influence [Ca2+](i) through well characterized pathways in higher eukaryotic cells were employed. [Ca2+](i) responses in the presence or absence of [Ca2+]0 were measured to asses the relative contribution of sequestration or extrusion processes in [Ca2+](i) homeostasis. In the presence of 0.5 mM [Ca2+]0, the ability of several agents to increase [Ca2+](i) was magnified in the order ionomycin >>> nigericin > thapsigargin > monensin > valinomycin. In contrast, preloading markedly enhanced the increase in [Ca2+](i) observed only in response to monensin. Manoalide, an inhibitor of phospholipase A2, enhanced the accumulation of [Ca2+](i) due to all agents tested, particularly ionomycin and thapsigargin. Our results suggest that sequestration of [Ca2+](i) involved storage sites sensitive to monensin and ionomycin whereas extrusion of Ca2+ may involve phospholipase A2 activity. A Na+/Ca2+ exchange mechanism did not appear to contribute to Ca2+ homeostasis.

Original languageEnglish (US)
Pages (from-to)80-86
Number of pages7
JournalJournal of Eukaryotic Microbiology
Volume45
Issue number1
StatePublished - Jan 1998

Fingerprint

trypomastigotes
Monensin
Ionomycin
Trypanosoma cruzi
homeostasis
Homeostasis
Thapsigargin
calcium
Nigericin
Valinomycin
Equidae
Phospholipases A2
Extracellular Space
Eukaryotic Cells
Buffers
Maintenance
Pharmacology
monensin
extrusion
phospholipase A2

Keywords

  • Chagas' disease
  • Hemoflaggelates
  • Ionomycin
  • Manoalide
  • Monensin
  • Nigericin
  • Thapsigargin
  • V alinomycin

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)
  • Applied Microbiology and Biotechnology
  • Microbiology

Cite this

Zhang, H. S., McDonald, T. V., Tanowitz, H. B., Wittner, M., Weiss, L. M., Bilezikian, J. P., & Morris, S. A. (1998). Intracellular Ca2+ homeostasis in trypomastigotes of Trypanosoma cruzi. Journal of Eukaryotic Microbiology, 45(1), 80-86.

Intracellular Ca2+ homeostasis in trypomastigotes of Trypanosoma cruzi. / Zhang, Hong Shan; McDonald, Thomas V.; Tanowitz, Herbert B.; Wittner, Murray; Weiss, Louis M.; Bilezikian, John P.; Morris, Stephen A.

In: Journal of Eukaryotic Microbiology, Vol. 45, No. 1, 01.1998, p. 80-86.

Research output: Contribution to journalArticle

Zhang, HS, McDonald, TV, Tanowitz, HB, Wittner, M, Weiss, LM, Bilezikian, JP & Morris, SA 1998, 'Intracellular Ca2+ homeostasis in trypomastigotes of Trypanosoma cruzi', Journal of Eukaryotic Microbiology, vol. 45, no. 1, pp. 80-86.
Zhang HS, McDonald TV, Tanowitz HB, Wittner M, Weiss LM, Bilezikian JP et al. Intracellular Ca2+ homeostasis in trypomastigotes of Trypanosoma cruzi. Journal of Eukaryotic Microbiology. 1998 Jan;45(1):80-86.
Zhang, Hong Shan ; McDonald, Thomas V. ; Tanowitz, Herbert B. ; Wittner, Murray ; Weiss, Louis M. ; Bilezikian, John P. ; Morris, Stephen A. / Intracellular Ca2+ homeostasis in trypomastigotes of Trypanosoma cruzi. In: Journal of Eukaryotic Microbiology. 1998 ; Vol. 45, No. 1. pp. 80-86.
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