All living cells must recruit metal ions to meet a certain quota, and the necessary concentration of many essential metals, including zinc, is relatively conserved among divergent species. However, in human erythrocytes parasitemized by the malaria parasite Plasmodium falciparum, zinc is found to accumulate in localized areas to a concentration of up to 20 times that of a normal erythrocyte. Interestingly, the intracellular levels of other essential metals such as copper and iron are not significantly altered by the presence of the parasite. In this proposal, we outline an approach to studying the mechanism by which the malaria parasite is able to dramatically alter the host cell zinc physiology. We believe that the proteins involved in zinc scavenging and hoarding serve as potential pharmaceutical targets in the effort to control this deadly parasite. This project will provide fundamental knowledge about this infectious disease and allow for the development of new treatments which will help to circumvent the drug resistances that currently hamper eradication of the disease.
We aim to study the metallobiochemistry of candidate zinc import and transport proteins to develop an in- depth understanding of how the intracellular malaria parasite can manipulate the zinc quota in order to infect and proliferate in the host. Specifically, we aim to (1) identify candidate proteins by studying P. falciparum transcription profiles under zinc stress conditions, (2) examine the roles of these and known transporter homologs in subcellularzinc localization, and (3) examine the subcellular localization of the proteins themselves as well as their ability to bind and transport zinc in vitro. The methods used to accomplish these aims will include DMA microarray analysis of mRNA, determination of total and local zinc content in variant strains using X-ray fluorescence and fluorescent zinc sensors, and detection of protein location via immunofluorescent assays. Relevance: It is estimated that nearly 10% of the world's population will suffer from clinical malaria each year, resulting in between 1.5 and 2.7 million deaths annually. One characteristic that sets red blood cells infected with the malaria parasite apart from healthy red blood cells is the presence of elevated levels of zinc. Therefore we believe that studying the role of zinc in malaria proliferation will lead to a better understanding of this disease as well as suggesting new types of anti-malarial therapies. ? ? ?
