Singh Subhash, Plassmeyer Matthew, Gaur Deepak, Miller Louis H
Malaria Cell Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12735 Twinbrook Parkway, Rockville, MD 20852, USA.
Proc Natl Acad Sci U S A. 2007 Dec 11;104(50):20043-8. doi: 10.1073/pnas.0709999104. Epub 2007 Nov 28.
Compartmentalization of proteins into subcellular organelles in eukaryotic cells is a fundamental mechanism of regulating complex cellular functions. Many proteins of Plasmodium falciparum merozoites involved in invasion are compartmentalized into apical organelles. We have identified a new merozoite organelle that contains P. falciparum rhomboid-1 (PfROM1), a protease that cleaves the transmembrane regions of proteins involved in invasion. By immunoconfocal microscopy, PfROM1 was localized to a single, thread-like structure on one side of the merozoites that appears to be in close proximity to the subpellicular microtubules. PfROM1 was not found associated with micronemes, rhoptries, or dense granules, the three identified secretory organelles of invasion. Release of merozoites from schizonts resulted in the movement of PfROM1 from the lateral asymmetric localization to the merozoite apical pole and the posterior pole. We have named this single thread-like organelle in merozoites, the mononeme.
真核细胞中蛋白质在亚细胞细胞器内的区室化是调节复杂细胞功能的一种基本机制。恶性疟原虫裂殖子中许多参与入侵的蛋白质被区室化到顶端细胞器中。我们鉴定出了一种新的裂殖子细胞器，它含有恶性疟原虫菱形蛋白酶-1（PfROM1），一种能切割参与入侵的蛋白质跨膜区的蛋白酶。通过免疫共聚焦显微镜观察，PfROM1定位于裂殖子一侧的单个丝状结构上，该结构似乎紧邻表膜下微管。未发现PfROM1与微小膜泡、棒状体或致密颗粒相关，这三种是已确定的参与入侵的分泌细胞器。裂殖子从裂殖体中释放导致PfROM1从侧向不对称定位移动到裂殖子顶端极和后端极。我们将裂殖子中的这种单丝状细胞器命名为单膜体。
