Mechanisms and significance of inter-organelle pyruvate transport in Toxoplasma gondii
Metabolism, Biochemistry and Genetics of Microorganisms
Final Report Abstract
Toxoplasma gondii is a widespread intracellular pathogen of livestock, wildlife and humans worldwide. In the last three decades, it has also become a model pathogen to understand the core molecular concepts of intracellular parasitism. One single species of genus Toxoplasma (i.e., T. gondii) can infect virtually all warm-blood organisms and several types of nucleated host cells. The parasite metabolism allows it to survive and reproduce in dissimilar nutritional environments encountered in diverse host cell types. The parasite uses glucose and glutamine as two significant sources of carbon to promote its asexual reproduction in mammalian cells. Both carbon sources are metabolized to pyruvate in the parasite cytosol, which serves as a central metabolite critical for the parasite's growth. It is utilized at different subcellular locations, including mitochondrion and apicoplast (a non-photosynthetic chloroplast relict and proven drug target against this group of parasites). This project focuses on potential pyruvate transporters located in the mitochondria and apicoplast membrane of Toxoplasma. The goal was to reveal the mechanism of pyruvate acquisition and its physiological significance in different organelles. The main research content includes the following aspects: 1. Subcellular localization and transmembrane topology of APC and MPC proteins 2. Biological roles of APC and MPC in the growth, reproduction, and pyruvate metabolism 3. Pyruvate transport activity of APC and MPC proteins 4. Mechanism of pyruvate transport by APCs and MPC proteins. During the project implementation, work was carried out progressively around the four main aspects mentioned above. TgAPCs' complex and composition in Toxoplasma gondii have been discovered, and the specific roles of TgMPCs have been clarified. The topological structure of TgAPCs on the parasite's apicoplast membrane and its physiological significance has been investigated. Metabolomics techniques have been utilized to analyze the roles of TgAPCs and TgMPCs in the parasite's central carbon metabolism. The heterologous expression system has further validated the transport ability of TgAPCs and TgMPCs for pyruvate. The research achievements of the project have great significance for understanding the carbon metabolism mechanism of Toxoplasma gondii and exploring new drug targets.
Publications
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The Mitochondrial Pyruvate Carrier Coupling Glycolysis and the Tricarboxylic Acid Cycle Is Required for the Asexual Reproduction of Toxoplasma gondii. Microbiology Spectrum, 11(2).
Lyu, Congcong; Chen, Yukun; Meng, Yanan; Yang, Jichao; Ye, Shu; Niu, Zhipeng; EI-Debs, Issam; Gupta, Nishith & Shen, Bang
