Obligatory intracellular parasitism by Ehrlichia chaffeensis and Anaplasma phagocytophilum involves caveolae and glycosylphosphatidylinositol-anchored proteins
Obligatory intracellular parasitism by Ehrlichia chaffeensis and Anaplasma phagocytophilum involves caveolae and glycosylphosphatidylinositol-anchored proteins
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DOI：
10.1046/j.1462-5822.2003.00322.x
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发表时间：
2003-11-01
影响因子：
3.4
通讯作者：
Rikihisa, Y
中科院分区：
文献类型：
--
作者：
Lin, MQ;Rikihisa, Y
强制性细胞内的人埃立克体病病原体查菲埃立克体和嗜吞噬细胞无形体分别在单核细胞/巨噬细胞和粒细胞中产生缺乏溶酶体标志物的独特复制区室。这些细菌的进入需要宿主磷脂酶C（PLC）-γ 2和蛋白酪氨酸激酶，但它们的进入途径仍不清楚。在这里，使用特定的抑制剂，双重免疫荧光标记和分馏的脂筏，我们证明，细菌进入和细胞内感染涉及富含胆固醇的脂筏或小窝和糖基磷脂酰肌醇（GPI）锚定蛋白。通过荧光显微镜，小窝标记蛋白caveolin-1与早期和复制细菌包涵体共定位。此外，在细菌早期包涵体中发现了酪氨酸磷酸化蛋白和PLC-γ 2。相比之下，网格蛋白没有发现任何夹杂物从任何细菌。早期内体标记转铁蛋白受体不存在于E. chaffeensis的复制包涵体中发现了这种蛋白质，而E. chaffeensis。此外，还对E. chaffeensis和A.将嗜吞噬细胞菌与Triton X-100不溶性筏级分共分级。细菌囊泡的形成，组装和保留细菌进入所必需的信号分子，并与再循环内体途径相互作用，可以确保这些专性细胞内细菌在初级宿主防御细胞中的存活。
Obligatory intracellular, human ehrlichiosis agents Ehrlichia chaffeensis and Anaplasma phagocytophilum create unique replicative compartments devoid of lysosomal markers in monocytes/macrophages and granulocytes respectively. The entry of these bacteria requires host phospholipase C (PLC)-gamma2 and protein tyrosine kinases, but their entry route is still unclear. Here, using specific inhibitors, double immunofluorescence labelling and the fractionation of lipid rafts, we demonstrate that bacterial entry and intracellular infection involve cholesterol-rich lipid rafts or caveolae and glycosylphosphatidylinositol (GPI)-anchored proteins. By fluorescence microscopy, caveolar marker protein caveolin-1 was co-localized with both early and replicative bacterial inclusions. Additionally, tyrosine-phosphorylated proteins and PLC-gamma2 were found in bacterial early inclusions. In contrast, clathrin was not found in any inclusions from either bacterium. An early endosomal marker, transferrin receptor, was not present in the early inclusions of E. chaffeensis, but was found in replicative inclusions of E. chaffeensis. Furthermore, several bacterial proteins from E. chaffeensis and A. phagocytophilum were co-fractionated with Triton X-100-insoluble raft fractions. The formation of bacteria-encapsulating caveolae, which assemble and retain signalling molecules essential for bacterial entry and interact with the recycling endosome pathway, may ensure the survival of these obligatory intracellular bacteria in primary host defensive cells.