The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.
PLoS Pathog. 2011 Sep;7(9):e1002199. doi: 10.1371/journal.ppat.1002199. Epub 2011 Sep 1.
Invasion of erythrocytes by Plasmodium falciparum involves a complex cascade of protein-protein interactions between parasite ligands and host receptors. The reticulocyte binding-like homologue (PfRh) protein family is involved in binding to and initiating entry of the invasive merozoite into erythrocytes. An important member of this family is PfRh5. Using ion-exchange chromatography, immunoprecipitation and mass spectroscopy, we have identified a novel cysteine-rich protein we have called P. falciparumRh5 interacting protein (PfRipr) (PFC1045c), which forms a complex with PfRh5 in merozoites. Mature PfRipr has a molecular weight of 123 kDa with 10 epidermal growth factor-like domains and 87 cysteine residues distributed along the protein. In mature schizont stages this protein is processed into two polypeptides that associate and form a complex with PfRh5. The PfRipr protein localises to the apical end of the merozoites in micronemes whilst PfRh5 is contained within rhoptries and both are released during invasion when they form a complex that is shed into the culture supernatant. Antibodies to PfRipr1 potently inhibit merozoite attachment and invasion into human red blood cells consistent with this complex playing an essential role in this process.
疟原虫入侵红细胞涉及寄生虫配体和宿主受体之间复杂的蛋白-蛋白相互作用级联。网织红细胞结合样同源物（PfRh）蛋白家族参与与入侵的裂殖子结合并启动进入红细胞。该家族的一个重要成员是 PfRh5。我们使用离子交换层析、免疫沉淀和质谱法鉴定了一种新的富含半胱氨酸的蛋白，我们称之为疟原虫 Rh5 相互作用蛋白（PfRipr）（PFC1045c），它在裂殖体中与 PfRh5 形成复合物。成熟的 PfRipr 分子量为 123 kDa，具有 10 个表皮生长因子样结构域和 87 个半胱氨酸残基分布在整个蛋白上。在成熟的裂殖体阶段，该蛋白被加工成两个多肽，它们相互结合并与 PfRh5 形成复合物。PfRipr 蛋白定位于裂殖体的顶端微线体中，而 PfRh5 则包含在顶端体中，当它们形成复合物并被释放到培养上清液中时，这两种蛋白都会被释放。针对 PfRipr1 的抗体强烈抑制裂殖体附着和入侵人红细胞，这表明该复合物在这一过程中起着至关重要的作用。
