For the protist parasite Entamoeba histolytica, endocytic processes, such as phagocytosis, are essential for its survival in the human gut. The actin cytoskeleton is involved in the formation of pseudopods and phagosomal vesicles by incorporating a number of actin-binding and modulating proteins along with actin in a temporal manner. The actin dynamics, which comprises polymerization, branching, and depolymerization is very tightly regulated and takes place directionally at the sites of initiation of phagocytosis. Formin and profilin are two actin-binding proteins that are known to regulate actin cytoskeleton dynamics and thereby, endocytic processes. In this article, we report the participation of formin and profilin in E. histolytica phagocytosis and propose that these two proteins interact with each other and their sequential recruitment at the site is required for the successful completion of phagocytosis. The evidence is based on detailed microscopic, live imaging, interaction studies, and expression downregulation. The cells downregulated for expression of formin show absence of profilin at the site of phagocytosis, whereas downregulation of profilin does not affect formin localization.

中文翻译：

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阿米巴福明和 profilin 的协同活性对吞噬作用至关重要

对于原生寄生虫溶组织内阿米巴，内吞过程，如吞噬作用，对于其在人体肠道中的生存至关重要。肌动蛋白细胞骨架通过以时间方式与肌动蛋白一起结合许多肌动蛋白结合和调节蛋白，参与伪足和吞噬体囊泡的形成。包括聚合、分支和解聚的肌动蛋白动力学受到非常严格的调节，并在吞噬作用的起始位点定向发生。Formin 和 profilin 是两种肌动蛋白结合蛋白，已知它们可以调节肌动蛋白细胞骨架动力学，从而调节内吞过程。在本文中，我们报告了福尔明和 profilin 在溶组织大肠杆菌中的参与吞噬作用并提出这两种蛋白质相互作用，并且它们在该位点的顺序募集是成功完成吞噬作用所必需的。证据基于详细的显微镜、实时成像、相互作用研究和表达下调。对于formin 表达下调的细胞在吞噬作用部位显示出profilin 的缺失，而profilin 的下调不影响formin 的定位。