David V, Gouin E, Troys M V, Grogan A, Segal A W, Ampe C, Cossart P
Unité des Interactions Bactéries-cellules, Institut Pasteur, 75724 Paris Cedex 15, France.
J Cell Sci. 1998 Oct;111 ( Pt 19):2877-84. doi: 10.1242/jcs.111.19.2877.
Actin assembly is involved in cell motility and intracellular movement of Listeria monocytogenes. Induction of Listeria actin tails is mediated by the surface protein ActA. The N-terminal domain of ActA is sufficient for this function. Cell components known to play a role in the actin-based motility of Listeria are VASP (vasodilatator-stimulated phosphoprotein), the multiprotein Arp2/3 complex and cofilin. VASP interacts with the central domain of ActA. Proteins interacting with the N-terminal domain of ActA have not been identified. To identify novel host cell components of ActA-induced actin tails, we used bovine brain extracts and an affinity approach with Listeria as matrix. Several known components of Listeria tails were isolated including VASP, Arp3 and cofilin. Cofilin was identified by peptide sequencing, and cofilin recruitment and Listeria tail length were found to be pH-dependent, in agreement with its recently reported role in enhancing actin filament turnover. In addition, three proteins not previously known to be associated with Listeria tails, coronin, Rac and capZ, were identified in our affinity approach. In infected cells, the localization of the identified proteins was studied by immunofluorescence. Our findings suggest that these latter proteins, which are known to play critical roles in cellular actin rearrangements, may also be involved in the dynamics of Listeria-induced actin assembly.
肌动蛋白组装参与细胞运动以及单核细胞增生李斯特菌的细胞内运动。李斯特菌肌动蛋白尾的诱导由表面蛋白ActA介导。ActA的N端结构域足以发挥此功能。已知在李斯特菌基于肌动蛋白的运动中起作用的细胞成分有血管扩张刺激磷蛋白（VASP）、多蛋白Arp2/3复合体和丝切蛋白。VASP与ActA的中央结构域相互作用。尚未鉴定出与ActA的N端结构域相互作用的蛋白质。为了鉴定ActA诱导的肌动蛋白尾的新型宿主细胞成分，我们使用牛脑提取物并采用以李斯特菌为基质的亲和方法。分离出了李斯特菌尾的几种已知成分，包括VASP、Arp3和丝切蛋白。通过肽测序鉴定出丝切蛋白，并且发现丝切蛋白的募集和李斯特菌尾的长度依赖于pH，这与其最近报道的增强肌动蛋白丝周转的作用一致。此外，在我们的亲和方法中鉴定出了三种先前未知与李斯特菌尾相关的蛋白质，冠蛋白、Rac和帽Z。在感染的细胞中，通过免疫荧光研究了鉴定出的蛋白质的定位。我们的发现表明，这些已知在细胞肌动蛋白重排中起关键作用的蛋白质，也可能参与李斯特菌诱导的肌动蛋白组装的动态过程。
