The IpaC carboxyterminal effector domain mediates Src-dependent actin polymerization during Shigella invasion of epithelial cells.
The IpaC carboxyterminal effector domain mediates Src-dependent actin polymerization during Shigella invasion of epithelial cells.
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DOI：
10.1371/journal.ppat.1000271
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发表时间：
2009-01
期刊：
影响因子：
6.7
通讯作者：
Van Nhieu, Guy Tran
中科院分区：
文献类型：
--
作者：
Mounier, Joelle;Popoff, Michel R.;Enninga, Jost;Frame, Margaret C.;Sansonetti, Philippe J.;Van Nhieu, Guy Tran
志贺氏菌是细菌性痢疾的病原体，通过局部重组肌动蛋白细胞骨架侵入上皮细胞。志贺氏菌入侵需要依赖于Src酪氨酸激酶和功能性细菌III型分泌（T3S）装置的肌动蛋白聚合。使用动态以及免疫荧光显微镜，我们表明，T3S易位元件IpaC允许招聘的Src激酶所需的肌动蛋白聚合在细菌进入网站在志贺氏菌进入的初始阶段。在侵袭过程开始时，Src募集发生在细菌细胞接触部位，与肌动蛋白聚合无关，并且在侵袭的T3 S效应子易位突变的志贺氏菌菌株中仍然观察到Src募集。极性突变的志贺菌菌株，表达低水平的转运蛋白组分IpaB和IpaC是完全精通Src招聘和细菌入侵。与此相反，志贺氏菌菌株突变的IpaC羧基末端效应结构域，是精通T3S效应易位不诱导Src的招聘。与IpaC在Src活化中的直接作用一致，细胞与IpaC最后72个羧基末端残基融合的Iota毒素Ia（IaC）组分一起孵育，IaC组分在与Ib组分结合后易位到细胞胞质溶胶中，导致Src依赖性皱褶形成。引人注目的是，IaC也诱导肌动蛋白结构类似于细菌进入病灶，富含激活的Src和抑制Src抑制剂PP2。这些结果表明，IpaC效应结构域决定Src依赖的肌动蛋白聚合和皱褶形成细菌入侵过程中。III型分泌系统（T3SS）存在于对人类、动物和植物致病的多种革兰氏阴性细菌中。这些分子装置允许将细菌毒力因子注射到宿主细胞中以操纵各种细胞功能。T3SS共享类似的功能特征。值得注意的是，宿主细胞接触触发两种T3SS底物的分泌，所述底物插入宿主细胞膜中以形成T3SS效应物注射所需的所谓的“转运子”。志贺氏菌，一种肠侵袭性病原体，负责细菌性痢疾，使用T3SS瞬时重组肌动蛋白细胞骨架，并诱导其内化到上皮细胞。一些注射志贺氏菌的T3 SS效应子参与细胞骨架重组，但这些效应子都不是诱导细菌入侵完全必要或足够的。我们在这里表明，除了其在注射细菌效应子中的作用外，转运子组分IpaC还诱导Src的募集和肌动蛋白聚合，从而驱动局部膜皱褶的形成。我们的研究结果表明，通过T3S转运蛋白组件的主要信号发生在细菌与宿主细胞膜相互作用的初始步骤。阻止志贺氏菌T3S转运子膜插入的化合物可能构成抗微生物剂的理想候选物。
Shigella, the causative agent of bacillary dysentery, invades epithelial cells by locally reorganizing the actin cytoskeleton. Shigella invasion requires actin polymerization dependent on the Src tyrosine kinase and a functional bacterial type III secretion (T3S) apparatus. Using dynamic as well as immunofluorescence microscopy, we show that the T3S translocon component IpaC allows the recruitment of the Src kinase required for actin polymerization at bacterial entry sites during the initial stages of Shigella entry. Src recruitment occurred at bacterial-cell contact sites independent of actin polymerization at the onset of the invasive process and was still observed in Shigella strains mutated for translocated T3S effectors of invasion. A Shigella strain with a polar mutation that expressed low levels of the translocator components IpaB and IpaC was fully proficient for Src recruitment and bacterial invasion. In contrast, a Shigella strain mutated in the IpaC carboxyterminal effector domain that was proficient for T3S effector translocation did not induce Src recruitment. Consistent with a direct role for IpaC in Src activation, cell incubation with the IpaC last 72 carboxyterminal residues fused to the Iota toxin Ia (IaC) component that translocates into the cell cytosol upon binding to the Ib component led to Src-dependent ruffle formation. Strikingly, IaC also induced actin structures resembling bacterial entry foci that were enriched in activated Src and were inhibited by the Src inhibitor PP2. These results indicate that the IpaC effector domain determines Src-dependent actin polymerization and ruffle formation during bacterial invasion. Type III secretion systems (T3SS) are present in a wide range of Gram-negative bacteria that are pathogenic to humans, animals, and plants. These molecular devices allow the injection of bacterial virulence factors into host cells to manipulate various cellular functions. T3SSs share similar functional features. Noticeably, host cell contact triggers the secretion of two T3SS substrates that insert into host cell membranes to form a so-called “translocator” required for the injection of T3SS effectors. Shigella, an enteroinvasive pathogen responsible for bacillary dysentery, uses a T3SS to transiently reorganize the actin cytoskeleton and to induce its internalization into epithelial cells. Some Shigella-injected T3SS effectors participate in cytoskeletal reorganization, but none of these effectors are totally necessary or sufficient to induce bacterial invasion. We show here that in addition to its role in the injection of bacterial effectors, the translocator component IpaC also induces the recruitment of Src and actin polymerization driving the formation of localized membrane ruffling. Our findings suggest that major signaling through T3S translocator components occurs during the initial steps of bacterial interaction with host cell membranes. Compounds that prevent membrane insertion of the Shigella T3S translocator would likely constitute ideal candidates for antimicrobial agents.
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DOI：
10.1083/jcb.147.3.683
发表时间：
1999-11-01
期刊：
The Journal of cell biology
影响因子：
--
作者：
Blocker A;Gounon P;Larquet E;Niebuhr K;Cabiaux V;Parsot C;Sansonetti P
通讯作者：
Sansonetti P
DOI：
10.1073/pnas.93.16.8437
发表时间：
1996-08-06
影响因子：
11.1
作者：
Blanke, SR;Milne, JC;Collier, RJ
通讯作者：
Collier, RJ
皮尔塔克蛋白和CRK在志贺氏菌入侵上皮细胞期间触发肌动蛋白聚合。
影响因子：
7.8
作者：
Bougneres, Laurence;Girardin, Stephane E;Weed, Scott A;Karginov, Andrei V;Olivo-Marin, Jean-Christophe;Parsons, J Thomas;Sansonetti, Philippe J;Van Nhieu, Guy Tran
通讯作者：
Van Nhieu, Guy Tran
影响因子：
48
作者：
Enninga, J;Mounier, J;Van Nhieu, GT
通讯作者：
Van Nhieu, GT
影响因子：
11.4
作者：
DEHIO, C;PREVOST, MC;SANSONETTI, PJ
通讯作者：
SANSONETTI, PJ