Abstract
Resistance towards known antimalarial drugs poses a significant problem, urging for novel drugs that target vital proteins in the malaria parasite Plasmodium falciparum. However, recombinant production of malaria proteins is notoriously difficult. To address this, we have investigated two putative K+ channels, PfKch1 and PfKch2, identified in the P. falciparum genome. We show that PfKch1 and PfKch2 and a C-terminally truncated version of PfKch1 (PfKch11−1094) could indeed be functionally expressed in vivo, since a K+-uptake deficient Saccharomyces cerevisiae strain was complemented by the P. falciparum cDNAs. PfKch11−1094-GFP and GFP-PfKch2 fusion proteins were overexpressed in yeast, purified and reconstituted in lipid bilayers to determine their electrophysiological activity. Single channel conductance amounted to 16 ± 1 pS for PfKch11−1094-GFP and 28 ± 2 pS for GFP-PfKch2. We predicted regulator of K+-conductance (RCK) domains in the C-terminals of both channels, and we accordingly measured channel activity in the presence of Ca2+.
Highlights
The recent decade has experienced a dramatic decrease in malaria prevalence and morbidity, which is partly due to combined efforts including rapid diagnostics, prompt treatment based on artemisinin combination therapies and the use of insecticide treated nets [1]
A number of membrane transporters from P. falciparum has subsequently been cloned and characterized in Xenopus laevis oocytes [9,10,11,12,13] and some have been shown to be crucial to asexual parasite development
Attempts to establish PfKch1 and PfKch2 knock outs were unsuccessful leading to the suggestion that they may be critical for asexual parasite development [15]
Summary
The recent decade has experienced a dramatic decrease in malaria prevalence and morbidity, which is partly due to combined efforts including rapid diagnostics, prompt treatment based on artemisinin combination therapies and the use of insecticide treated nets [1]. An estimated 228 million cases still occur annually, leading to around 405,000 deaths a year [2], and the occurrence of resistance towards several artemisinin based combination therapies calls for the development of new Bioinformatics analysis of the P. falciparum genome has revealed new potential drug targets such as membrane transporters, channels and pores [7, 8]. Gene disruption studies with PbKch showed that this channel in P. berghei is essential for sexual-stage parasite development in the mosquito vector [17]. PbKch, has recently been examined in a genetic knock out model and found to be non-essential for K+ transport across the parasite plasma membrane, whether in the intra-erythrocytic or in the mosquito residing stages [18]. K + channels have are excellent targets in drug development, and the potential for the Plasmodium channels as targets for treatment of malaria has been discussed in several reviews (see e.g., 7, 8, 19)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
