Membrane Transport Proteins of the Malaria Parasite

疟疾寄生虫有一个复杂的生命周期，有细胞内和细胞外阶段，在此期间，它遇到各种环境，许多是恶劣的。在每个阶段，寄生虫必须有专门的适应性，以获得营养物质，清除可溶性代谢废物，并维持离子梯度。膜转运蛋白可能介导所有这些。膜片钳方法已被用来确定两个这些离子通道的红细胞阶段。首先，在被成熟寄生虫感染的红细胞表面上有一个小的（5 pS）离子通道。该通道主要可渗透阴离子和小营养素，被几种通道阻断剂抑制（尽管很差），并且以约2000个拷贝/细胞存在。其次，在细胞内寄生虫周围的膜上有一个单独的大（150 pS）非选择性通道。第二个通道的孔径为23埃，起着分子筛的作用，为寄生虫提供红细胞胞质溶胶中的可溶性营养物质。我们正在努力进一步描述这些通道并克隆它们的基因。因为它们在寄生虫中的重要作用？利用疟疾基因组数据库和卵母细胞的异源表达，也将鉴定出疟原虫的其他膜转运蛋白。- 疟疾，离子通道，营养素，恶性疟原虫，转运蛋白，膜片钳

The malaria parasite has a complex life cycle with intra- and extra- cellular stages, during which it encounters a variety of environments, many harsh. At each stage, the parasite must have specialized adaptations for acquisition of nutrients, removal of soluble metabolic wastes, and maintenance of ionic gradients. Membrane transport proteins likely mediate all of these. The patch clamp method has been used to identify two of these ion channels for the erythrocytic stage. First, there is a small (5 pS) ion channel on the surface of red cells infected with mature parasites. This channel is primarily permeable to anions and small nutrients, inhibited by several channel blockers (albeit poorly), and is present at ~2000 copies/cell. Second, there is a separate large (150 pS) nonselective channel on the membrane surrounding the intracellular parasite. This second channel has a pore size of 23 angstroms and functions as a molecular sieve, providing the parasite access to soluble nutrients in red cell cytosol. We are working to further characterize these channels and clone their genes. Because of their important roles in the parasite?s adaptation to the red cell, they may be ideal targets for new channel blockers or vaccines.Other membrane transporters of the parasite will also be identified by using the growing malaria genome database and heterologous expression in oocytes. - Malaria, ion channels, nutrients, Plasmodium falciparum, transporters, patch clamp