EspFU is a translocated EHEC effector that interacts with Tir and N-WASP and promotes nck-independent actin assembly
EspFU is a translocated EHEC effector that interacts with Tir and N-WASP and promotes nck-independent actin assembly
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DOI：
10.1016/j.devcel.2004.07.004
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发表时间：
2004-08-01
影响因子：
11.8
通讯作者：
Leong, JM
中科院分区：
文献类型：
--
作者：
Campellone, KG;Robbins, D;Leong, JM
几种微生物病原体包括肠致病性E.大肠杆菌（EPEC）利用哺乳动物酪氨酸激酶信号级联来募集Nck接头蛋白并激活N-WASP-Arp 2/3介导的肌动蛋白组装。为了促进局部肌动蛋白“基座形成”，EPEC将细菌效应蛋白Tir易位到质膜中，在质膜中它被酪氨酸磷酸化并结合Nck。肠出血性大肠大肠杆菌（EHEC）也产生Tir依赖性抗体，但不存在磷酸酪氨酸和Nck募集。为了确定额外的EHEC效应刺激磷酸酪氨酸独立的肌动蛋白组装，我们系统地产生EHEC突变体含有特定的缺失在推定的致病性岛。在0.33 Mb的缺失序列中，只有一个ORF是形成基座的关键。它位于前噬菌体-U内，并编码与已知的效应子EspF相似的蛋白质。这种富含脯氨酸的蛋白EspF（U）是EPEC中唯一不存在的肌动蛋白组装的EHEC效应物。尽管EHEC Tir不能有效地募集N-WASP或触发肌动蛋白聚合，但EspF（U）与Tir缔合，结合N-WASP，并有效地刺激Nck-非依赖性肌动蛋白组装。
Several microbial pathogens including enteropathogenic E. coli (EPEC) exploit mammalian tyrosine-kinase signaling cascades to recruit Nck adaptor proteins and activate N-WASP-Arp2/3-mediated actin assembly. To promote localized actin "pedestal formation," EPEC translocates the bacterial effector protein Tir into the plasma membrane, where it is tyrosine-phosphorylated and binds Nck. Enterohemorrhagic E. coli (EHEC) also generates Tir-dependent pedestals, but in the absence of phosphotyrosines and Nck recruitment. To identify additional EHEC effectors that stimulate phosphotyrosine-independent actin assembly, we systematically generated EHEC mutants containing specific deletions in putative pathogenicity-islands. Among 0.33 Mb of deleted sequences, only one ORF was critical for pedestal formation. It lies within prophage-U, and encodes, a protein similar to the known effector EspF. This proline-rich protein, EspF(U), is the only EHEC effector of actin assembly absent from EPEC. Whereas EHEC Tir cannot efficiently recruit N-WASP or trigger actin polymerization, EspF(U) associates with Tir, binds N-WASP, and potently stimulates Nck-independent actin assembly.