Display options
Share it on

Physiol Rep. 2013 Dec 29;1(7):e00186. doi: 10.1002/phy2.186. eCollection 2013 Dec 01.

Voltage-dependent potassium currents expressed in Xenopus laevis oocytes after injection of mRNA isolated from trophozoites of Giardia lamblia (strain Portland-1).

Physiological reports

Arturo Ponce, Enedina Jimenez-Cardoso, Leticia Eligio-Garcia

Affiliations

  1. Department of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies IPN, México City, Mexico.
  2. Parasitology Research Laboratory, Children Hospital of México "Federico Gomez", Mexico City, México.

PMID: 24744864 PMCID: PMC3970746 DOI: 10.1002/phy2.186

Abstract

Despite its importance as a health problem issue, almost nothing is known about the membrane physiology of Giardia lamblia and practically there exist no information so far regarding the variety and properties of ion channels that this protozoan parasite possesses. To address this subject we resorted to an indirect method, consisting in the injection of mRNA and further characterization of ion currents in Xenopus oocytes. In this work, we show that oocytes injected with mRNA isolated from cultured trophozoites of G. lamblia, strain Portland-1 express novel potassium currents that appear over the second day after injection and show time- and voltage-dependent activation followed by a slow inactivation. They start activating at -90 mV, with V1/2 of -30 mV; its time constant of activation (at +60 mV) is 0.11 sec, whereas that of inactivation is 1.92 sec, V1/2 = -44.6 mV. Such K currents were effectively blocked by K channel blockers TEA and 4AP, as well as Ba(2+), quinine, quinidine, charybdotoxin, dendrotoxin-1, capsaicin, margatoxin, and diltiazem. These results suggest that such currents are the result of expression of Giardia's voltage-gated K channels heterologously expressed in Xenopus laevis oocytes.

Keywords: Giardia lamblia; K currents; Xenopus oocytes; voltage clamp

References

  1. Biophys J. 1990 Jun;57(6):1117-23 - PubMed
  2. J Gen Physiol. 2011 Dec;138(6):641-9 - PubMed
  3. Br J Pharmacol. 1994 Jun;112(2):616-24 - PubMed
  4. Physiol Rev. 2012 Oct;92(4):1865-913 - PubMed
  5. Mol Biochem Parasitol. 2000 Apr 30;108(1):141-5 - PubMed
  6. Methods Enzymol. 1992;207:319-39 - PubMed
  7. J Pharmacol Exp Ther. 1996 Nov;279(2):856-64 - PubMed
  8. Annu Rev Physiol. 1990;52:399-414 - PubMed
  9. J Neurosci. 1991 Apr;11(4):918-27 - PubMed
  10. Microbiol Rev. 1991 Dec;55(4):706-32 - PubMed
  11. Mol Biotechnol. 1995 Apr;3(2):101-15 - PubMed
  12. FEMS Microbiol Lett. 2000 Nov 1;192(1):153-7 - PubMed
  13. J Biol Chem. 2011 Nov 18;286(46):39823-8 - PubMed
  14. Nucleic Acids Res. 2009 Jan;37(Database issue):D526-30 - PubMed
  15. Annu Rev Microbiol. 1996;50:679-705 - PubMed
  16. Trans R Soc Trop Med Hyg. 1983;77(4):467-9 - PubMed
  17. J Pharmacol Exp Ther. 1998 Jun;285(3):1051-60 - PubMed
  18. Mol Pharmacol. 1993 Jul;44(1):180-90 - PubMed
  19. Am J Physiol. 1996 Mar;270(3 Pt 1):C711-30 - PubMed
  20. Exp Parasitol. 2007 Jun;116(2):163-70 - PubMed
  21. Methods Mol Biol. 1995;49:317-40 - PubMed
  22. Proc Natl Acad Sci U S A. 2006 Mar 28;103(13):5120-4 - PubMed
  23. Proc Natl Acad Sci U S A. 2004 Apr 13;101(15):5318-24 - PubMed
  24. Ann N Y Acad Sci. 1999 Apr 30;868:233-85 - PubMed
  25. Arch Med Res. 2000 Jul-Aug;31(4 Suppl):S285-7 - PubMed
  26. CRC Crit Rev Biochem. 1987;22(4):317-87 - PubMed
  27. Cell Physiol Biochem. 2012;30(5):1254-70 - PubMed
  28. Biull Eksp Biol Med. 1997 Sep;124(9):271-4 - PubMed
  29. Mol Microbiol. 2007 Aug;65(4):1006-17 - PubMed
  30. J Bioenerg Biomembr. 1991 Aug;23(4):615-46 - PubMed
  31. Microb Drug Resist. 2002 Spring;8(1):15-26 - PubMed
  32. Pharmacol Rev. 1995 Sep;47(3):387-573 - PubMed
  33. Mol Microbiol. 2006 Feb;59(4):1249-61 - PubMed
  34. Cell Cycle. 2009 Nov 1;8(21):3527-36 - PubMed
  35. Methods Enzymol. 1992;207:266-79 - PubMed
  36. J Biol Chem. 1993 Sep 5;268(25):18866-74 - PubMed
  37. J Membr Biol. 2005 Jun;205(3):159-73 - PubMed
  38. Exp Parasitol. 2008 Nov;120(3):242-8 - PubMed

Publication Types