Interaction between the membrane protein of a pathogen and insect microfilament complex determines insect-vector specificity
Interaction between the membrane protein of a pathogen and insect microfilament complex determines insect-vector specificity
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DOI：
10.1073/pnas.0508668103
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发表时间：
2006-03-14
影响因子：
11.1
通讯作者：
Namba, S
中科院分区：
文献类型：
--
作者：
Suzuki, S;Oshima, K;Namba, S
许多昆虫传播的病原体是由特定的昆虫物种传播的，而不是由其他物种传播的，即使它们是密切相关的。这种严格的病原体-昆虫特异性的分子机制知之甚少。紫菀植原体（Phytoplasma asteris），OY株系W（OY），是通过取食汁液的昆虫载体（叶蝉）在植物间传播的植物病原性细菌。我们的研究集中在植原体细胞表面的一个丰富的膜蛋白，称为抗原膜蛋白（antigenic membrane protein，简称AMMP），它与任何已报道的功能蛋白都不同源。植原体感染的昆虫的免疫荧光显微镜显示，OY植原体被定位到周围的昆虫的肠道内脏平滑肌的微丝。亲和柱分析表明，昆虫肌动蛋白，肌球蛋白重链，肌球蛋白轻链与三种昆虫蛋白质形成复合物。Amp-微丝复合体在所有OY-传输叶蝉物种中检测到，但在非OY-传输叶蝉中没有检测到，这表明Amp-微丝复合体的形成与叶蝉的植原体传输能力相关。虽然有几项研究报道了病原体和哺乳动物微丝之间的相互作用，但这是细菌表面蛋白和昆虫细胞中宿主微丝之间宿主特异性相互作用的一个例子。我们的数据还表明，利用宿主微丝可能是一个通用的系统，为病原菌感染哺乳动物或昆虫。
Many insect-transmissible pathogens are transmitted by specific insect species and not by others, even if they are closely related. The molecular mechanisms underlying such strict pathogen-insect specificity are poorly understood. Candidatus Phytoplasma asteris, OY strain, line W (OY), is a phytopathogenic bacterium transmitted from plant to plant by sap-feeding insect vectors (leafhoppers). Our study focused on an abundant cell-surface membrane protein of the phytoplasma named antigenic membrane protein (Amp), which is not homologous with any reported functional protein. Immunofluorescence microscopy of the phytoplasma-infected insect showed that OY phytoplasma was localized to the microfilaments of the visceral smooth muscle surrounding the insect's intestinal tract. The affinity column assay showed that Amp forms a complex with three insect proteins: actin, myosin heavy chain, and myosin light chain. Amp-microfilament complexes were detected in all OY-transmitting leafhopper species, but not in the non-OY-transmitting leafhoppers, suggesting that the formation of the Amp-microfilament complex is correlated with the phytoplasma-transmitting capability of leafhoppers. Although several studies have reported interactions between pathogens and mammalian microfilaments, this is an example of host-specific interactions between a bacterial surface protein and a host microfilament in insect cells. Our data also suggest that the utilization of a host microfilament may be a universal system for pathogenic bacteria infecting mammals or insects.