School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
Nat Commun. 2011;2:230. doi: 10.1038/ncomms1199.
Phagocytosis is a process whereby particles are taken in by cells through mechanisms superficially similar to those for endocytosis. It serves a wide range of functions, from providing nutrition in unicellular organisms to initiation of both innate and adaptive immunity in vertebrates. In the protozoan parasite Entamoeba histolytica, it has an essential role in survival and pathogenesis. In this study, we show that EhC2PK, a C2-domain-containing protein kinase, and the Ca²(+) and actin-binding protein, EhCaBP1, are involved in the initiation of phagocytosis in E. histolytica. Conditional suppression of EhC2PK expression and overexpression of a mutant form reveals its role in the initiation of phagocytic cups. EhC2PK binds phosphatidylserine in the presence of Ca²(+) and thereby recruits EhCaBP1 and actin to the membrane. Identification of these proteins in phagocytosis is an important step in amoebic biology and these molecules could be the important targets for developing novel therapies against amoebiasis.
吞噬作用是细胞通过与胞吞作用表面上相似的机制摄取颗粒的过程。它具有广泛的功能，从为单细胞生物提供营养到启动脊椎动物的先天和适应性免疫。在原生动物寄生虫溶组织内阿米巴中，它在生存和发病机制中起着至关重要的作用。在这项研究中，我们表明，含 C2 结构域的蛋白激酶 EhC2PK 和 Ca²（+）和肌动蛋白结合蛋白 EhCaBP1 参与了溶组织内阿米巴吞噬作用的启动。EhC2PK 表达的条件性抑制和突变体形式的过表达揭示了其在吞噬杯起始中的作用。EhC2PK 在 Ca²（+）存在下结合磷脂酰丝氨酸，从而将 EhCaBP1 和肌动蛋白募集到膜上。这些蛋白在吞噬作用中的鉴定是阿米巴生物学的重要步骤，这些分子可能是开发针对阿米巴病的新型治疗方法的重要靶点。
