Molecular and electrophysiological characterization of a novel cation channel of Trypanosoma cruzi.
We report the identification, functional expression, purification, reconstitution and electrophysiological characterization of a novel cation channel (TcCat) from Trypanosoma cruzi, the etiologic agent of Chagas disease. This channel is potassium permeable and shows inward rectification in the presence of magnesium. Western blot analyses with specific antibodies indicated that the protein is expressed in the three main life cycle stages of the parasite. Surprisingly, the parasites have the unprecedented ability to rapidly change the localization of the channel when they are exposed to different environmental stresses. TcCat rapidly translocates to the tip of the flagellum when trypomastigotes are submitted to acidic pH, to the plasma membrane when epimastigotes are submitted to hyperosmotic stress, and to the cell surface when amastigotes are released to the extracellular medium. Pharmacological block of TcCat activity also resulted in alterations in the trypomastigotes ability to respond to hyperosmotic stress. We also demonstrate the feasibility of purifying and reconstituting a functional ion channel from T. cruzi after recombinant expression in bacteria. The peculiar characteristics of TcCat could be important for the development of specific inhibitors with therapeutic potential against trypanosomes.
Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America. vjimen@uga.edu
Veronica
V
Jimenez
Roberto
R
Docampo
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D005455:Fluorescent Antibody Technique; D008081:Liposomes; D008969:Molecular Sequence Data; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000502:physiology*; D021381:Protein Transport / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014349:Trypanosoma cruzi / Q000502:physiology*
D008081:Liposomes; D015221:Potassium Channels