Identification and disruption of a rhoptry-localized homologue of sodium hydrogen exchangers in Toxoplasma gondii

Int J Parasitol. 2005 Mar;35(3):285-91. doi: 10.1016/j.ijpara.2004.11.015. Epub 2005 Jan 21.


Na+/H+ exchangers (NHEs) are ubiquitous membrane proteins that catalyze the exchange of Na+ for H+ and are critical in pH and cell volume regulation, as well as osmotolerance. In this study, we identify and characterize a novel NHE, TgNHE2, in Toxoplasma gondii. Immunofluorescence studies show that TgNHE2 is localized to the rhoptries, secretory organelles involved in invasion. TgNHE2 is the first intracellular NHE to be characterized in a protozoan parasite and its localization suggests possible roles for the rhoptries in osmotolerance and/or as secretory lysosomes-like granules.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Membrane Proteins / analysis*
  • Membrane Proteins / genetics
  • Membrane Proteins / physiology
  • Molecular Sequence Data
  • Organelles / chemistry*
  • Protozoan Proteins / analysis*
  • Protozoan Proteins / genetics
  • Protozoan Proteins / physiology
  • Sodium-Hydrogen Exchangers / analysis*
  • Sodium-Hydrogen Exchangers / physiology
  • Toxoplasma / chemistry*
  • Water-Electrolyte Balance / physiology


  • Membrane Proteins
  • Protozoan Proteins
  • Sodium-Hydrogen Exchangers

Associated data

  • GENBANK/AY735393