Balañá María Eugenia, Niedergang Florence, Subtil Agathe, Alcover Andrés, Chavrier Philippe, Dautry-Varsat Alice
Unité de Biologie des Interactions Cellulaires, Institut Pasteur, CNRS URA 2582, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France.
J Cell Sci. 2005 May 15;118(Pt 10):2201-10. doi: 10.1242/jcs.02351. Epub 2005 Apr 19.
The obligate intracellular bacterium Chlamydia penetrates the host epithelial cell by inducing cytoskeleton and membrane rearrangements reminiscent of phagocytosis. Here we report that Chlamydia induces a sharp and transient activation of the endogenous small GTP-binding protein ARF6, which is required for efficient uptake. We also show that a downstream effector of ARF6, phosphatidylinositol 4-phosphate 5-kinase and its product, phosphatidylinositol 4,5-bisphosphate were instrumental for bacterial entry. By contrast, ARF6 activation of phospholipase D was not required for Chlamydia uptake. ARF6 activation was necessary for extensive actin reorganization at the invasion sites. Remarkably, these signalling players gathered with F-actin in a highly organized three-dimensional concentric calyx-like protrusion around invasive bacteria. These results indicate that ARF6, which controls membrane delivery during phagocytosis of red blood cells in macrophages, has a different role in the entry of this small bacterium, controlling cytoskeletal reorganization.
专性胞内细菌衣原体通过诱导细胞骨架和膜重排侵入宿主上皮细胞,这种重排类似于吞噬作用。在此,我们报告衣原体可诱导内源性小GTP结合蛋白ARF6迅速且短暂的激活,这是有效摄取所必需的。我们还表明,ARF6的下游效应物磷脂酰肌醇4-磷酸5-激酶及其产物磷脂酰肌醇4,5-二磷酸对细菌进入起重要作用。相比之下,衣原体摄取并不需要ARF6激活磷脂酶D。ARF6激活对于侵袭部位广泛的肌动蛋白重组是必需的。值得注意的是,这些信号分子与F-肌动蛋白在侵袭性细菌周围高度组织化的三维同心花萼样突起中聚集。这些结果表明,在巨噬细胞吞噬红细胞过程中控制膜递送的ARF6,在这种小细菌的进入过程中具有不同作用,即控制细胞骨架重组。