Conserved amongst all eukaryotes is a family of mitochondrial carrier proteins (SLC25A) responsible for the import of various solutes across the inner mitochondrial membrane. We previously reported that the human parasite Trypanosoma brucei possesses 26 SLC25A proteins (TbMCPs) amongst which two, TbMCP11 and TbMCP8, were predicted to function as phosphate importers. The transport of inorganic phosphate into the mitochondrion is a prerequisite to drive ATP synthesis by substrate level and oxidative phosphorylation and thus crucial for cell viability. In this paper we describe the functional characterization of TbMCP11. In procyclic form T. brucei, the RNAi of TbMCP11 blocked ATP synthesis on mitochondrial substrates, caused a drop of the mitochondrial oxygen consumption and drastically reduced cell viability. The functional complementation in yeast and mitochondrial swelling experiments suggested a role for TbMCP11 as inorganic phosphate carrier. Interestingly, procyclic form T. brucei cells in which TbMCP11 was depleted displayed an inability to either replicate or divide the kinetoplast DNA, which resulted in a severe cytokinesis defect.

在所有真核生物中，保守的是线粒体载体蛋白（SLC25A）家族，负责跨线粒体内膜导入各种溶质。我们以前曾报道过，人类寄生虫布鲁氏锥虫拥有26种SLC25A蛋白（Tb MCP），其中两个Tb MCP11和Tb MCP8被预测为磷酸盐的输入物质。无机磷酸盐向线粒体的运输是通过底物水平和氧化磷酸化来驱动ATP合成的前提条件，因此对于细胞活力至关重要。在本文中，我们描述了Tb MCP11的功能特性。Tb的RNAi以前环形式T. bruceiMCP11阻断了线粒体底物上的ATP合成，导致线粒体耗氧量下降并大大降低了细胞活力。酵母和线粒体肿胀实验中的功能互补表明Tb MCP11作为无机磷酸盐载体的作用。有趣的是，procyclic形式布氏锥虫，其中细胞铽MCP11耗尽显示的不能复制或者或划分动基体DNA，这导致了严重的胞质分裂缺陷。