Masters Thesis

Biophysical and Physiological Characterization of a Calcium Activated Potassium Channel in Trypanosoma Cruzi (tccakc)

Trypanosoma cruzi is the protozoan parasite that is the causative agent of Chagas disease. This disease is endemic to Latin America but has spread to other non-endemic areas due to globalization. the disease currently lacks an FDA approved treatment, and current treatments are non-specific and have severe side effects. More specific and novel pathways of T. cruzi must be identified to develop more effective treatments of Chagas. One potential target is ion channels, which play a wide array of important physiological roles throughout eukaryotic organisms. We have identified and characterized a calcium-activated potassium channel in Trypanosoma cruzi, TcCaKC, that is hypothesized to contribute to significant physiological function in T. cruzi. Using two-electrode voltage clamp method with Xenopus laevis oocytes heterologously expressing TcCaKC, the channel has been shown to be calcium-activated. This calcium activation causes an increase in current and a negative shift in reversal potential that is blocked by barium. These results suggest TcCaKC is a potassium conducting channel. Characterization of a selectivity filter mutant also supports this hypothesis. Fluorometric recording of parasites that were knockouts of TcCaKC showed that the channel plays a significant role in maintaining membrane potential, intracellular calcium, and pH of the parasite. Full biophysical characterization of this novel ion channel could potentially lead to the identification of a unique drug target for T. cruzi infection treatment.

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