The Yersinia tyrosine phosphatase YopH targets a novel adhesion-regulated signalling complex in macrophages
The Yersinia tyrosine phosphatase YopH targets a novel adhesion-regulated signalling complex in macrophages
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DOI：
10.1046/j.1462-5822.2000.00061.x
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发表时间：
2000-10-01
影响因子：
3.4
通讯作者：
Bliska, JB
中科院分区：
文献类型：
--
作者：
Black, DS;Marie-Cardine, A;Bliska, JB
耶尔森菌蛋白酪氨酸磷酸酶（PTP） YopH通过III型分泌系统转运到真核细胞中，这需要细菌-宿主细胞接触。YopH由两个模块化效应域组成：位于n端区域的底物结合域（残基1-130）和位于c端区域的PTP催化域（残基206-468）。先前的研究表明，YopH选择性靶向小鼠巨噬细胞中分子量约为120 kDa （p120）和55 kDa （p55）的酪氨酸磷酸化蛋白。已经证明p120实际上代表两个酪氨酸磷酸化的靶蛋白Cas和Fyb。我们利用YopH的底物结合域从J774A.1巨噬细胞裂解物中亲和纯化酪氨酸磷酸化的靶蛋白。蛋白微测序鉴定p55为小鼠SKAP-HOM。在体外和巨噬细胞中证实了SKAP-HOM与催化无活性形式的YopH之间的直接相互作用。此外，我们获得的证据表明，SKAP-HOM在巨噬细胞粘附反应中酪氨酸磷酸化，并与Fyb形成信号复合物。我们认为YopH对SKAP-HOM和Fyb的去磷酸化使耶尔森菌能够干扰巨噬细胞中一种新的粘附调节信号转导途径。
The Yersinia protein tyrosine phosphatase (PTP) YopH is translocated into eukaryotic cells by a type III secretion system that requires bacterial-host cell contact. YopH is composed of two modular effector domains: a substrate-binding domain located in the N-terminal region (residues 1-130) and a PTP catalytic domain located in the C-terminal region (residues 206-468). Previous studies have shown that YopH selectively targets tyrosine-phosphorylated proteins of approximate molecular weight 120 kDa (p120) and 55 kDa (p55) in murine macrophages. It has been demonstrated that p120 actually represents two tyrosine-phosphorylated target proteins, Cas and Fyb. We used the substrate-binding domain of YopH to affinity purify tyrosine-phosphorylated target proteins from lysates of J774A.1 macrophages. Protein microsequencing identified p55 as murine SKAP-HOM. Direct interaction between SKAP-HOM and a catalytically inactive form of YopH was demonstrated in vitro and in macrophages. In addition, we obtained evidence that SKAP-HOM is tyrosine phosphorylated in response to macrophage cell adhesion and that it forms a signalling complex with Fyb. We suggest that dephosphorylation of SKAP-HOM and Fyb by YopH allows yersiniae to interfere with a novel adhesion-regulated signal transduction pathway in macrophages.