Interactions of Encephalitozoon cuniculi Polar Tube Proteins
Interactions of Encephalitozoon cuniculi Polar Tube Proteins
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DOI：
10.1128/iai.01205-09
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发表时间：
2010-06-01
影响因子：
3.1
通讯作者：
Weiss, Louis M.
中科院分区：
文献类型：
--
作者：
Bouzahzah, Boumediene;Nagajyothi, Fnu;Weiss, Louis M.
微孢子虫是真核生物，专性胞内生物，由小孢子定义，含有单个侵入细胞器，极管，其盘绕在孢子内部。当这些寄生虫感染宿主细胞时，极管从孢子的前极排出，刺穿细胞，并将孢子质转移到宿主的细胞质中。在该结构中已鉴定出三种极管蛋白（PTP1、PTP2和PTP3）。这些蛋白质在极管的组装和功能中的相互作用尚不清楚。本研究旨在研究兔脑炎原虫极管蛋白（EcPTPs）的蛋白质相互作用。免疫荧光和免疫电镜证实EcPTP1，EcPTP2和EcPTP3的共同定位的极管。使用交联剂的实验表明EcPTP1、EcPTP2和EcPTP3在极管内形成复合物，这通过使用EcPTP1抗血清的免疫沉淀得到证实。酵母双杂交分析表明，全长EcPTP1，EcPTP2和EcPTP3在体内相互作用。EcPTP 1的N和C末端都参与了这些相互作用，但该蛋白的中心区域（包含重复基序）没有参与。对极管蛋白及其结构相互作用的进一步研究可能有助于阐明极管在入侵过程中的形成。
Microsporidia are eukaryotic, obligate intracellular organisms defined by small spores that contain a single invasion organelle, the polar tube, which coils around the interior of the spore. When these parasites infect host cells, the polar tube is discharged from the anterior pole of the spore, pierces the cell, and transfers sporoplasm into the cytoplasm of the host. Three polar tube proteins (PTP1, PTP2, and PTP3) have been identified in this structure. The interactions of these proteins in the assembly and function of the polar tube are not known. This study was undertaken to examine the protein interactions of the Encephalitozoon cuniculi polar tube proteins (EcPTPs). Immunofluorescence and immunoelectron microscopy confirmed the colocalization of EcPTP1, EcPTP2, and EcPTP3 to the polar tube. Experiments using cross-linkers indicated that EcPTP1, EcPTP2, and EcPTP3 form a complex in the polar tube, which was confirmed by immunoprecipitation using EcPTP1 antiserum. Yeast two-hybrid analysis revealed that full-length EcPTP1, EcPTP2, and EcPTP3 interact with each other in vivo. Both the N and C termini of EcPTP1 were involved in these interactions, but the central region of this protein, which contains a repetitive motif, was not. Further studies of polar tube proteins and their structural interactions may help elucidate the formation of the polar tube during the invasion process.