Identification of a conserved membrane localization domain within numerous large bacterial protein toxins
Identification of a conserved membrane localization domain within numerous large bacterial protein toxins
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DOI：
10.1073/pnas.0908700107
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发表时间：
2010-03-23
影响因子：
11.1
通讯作者：
Satchell, Karla J. F.
中科院分区：
文献类型：
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作者：
Geissler, Brett;Tungekar, Rehman;Satchell, Karla J. F.
霍乱弧菌是引起腹泻病霍乱的病原体。许多毒力因素有助于肠道定植和疾病，包括多功能自动加工RTX毒素（MARTX(Vc)）。MARTX（Vc）的rho失活结构域（RID）负责灭活小gtpase的rho家族，导致肌动蛋白细胞骨架的解聚。基于RID的缺失分析以确定最小功能域，我们在RID的N端发现了一个亚域，该亚域与多杀性巴氏杆菌毒素的靶向C1域的膜同源。当在HeLa细胞内短暂表达时，RID与该亚结构域的GFP融合与质膜标记共定位，并且可以在亚细胞分离后的膜部分中发现。这种c1样亚结构域存在于多种细菌毒素家族中，包括所有梭状菌葡萄糖基转移酶毒素和各种MARTX毒素。gfp与这些同源结构域的融合也与膜相关，表明这是一个保守的膜定位结构域（MLD）。我们已经确定了三个残基（Y23, S68, R70）是正确定位一个而不是所有MLDs所必需的。此外，我们发现，用创伤弧菌MARTX毒素的两个不同效应域的MLDs替换RID MLD可以恢复RID活性，这表明这些MLDs之间存在功能重叠。本研究描述了在多种大型细菌毒素中发现的一个保守质膜靶向结构域家族的初步识别。
Vibrio cholerae is the causative agent of the diarrheal disease cholera. Many virulence factors contribute to intestinal colonization and disease including the Multifunctional Autoprocessing RTX toxin (MARTX(Vc)). The Rho-inactivation domain (RID) of MARTX(Vc) is responsible for inactivating the Rho-family of small GTPases, which leads to depolymerization of the actin cytoskeleton. Based on a deletion analysis of RID to determine the minimal functional domain, we have identified a subdomain at the N terminus of RID that is homologous to the membrane targeting C1 domain of Pasteurella multocida toxin. A GFP fusion to this subdomain from RID colocalized with a plasma membrane marker when transiently expressed within HeLa cells and can be found in the membrane fraction following subcellular fractionation. This C1-like subdomain is present in multiple families of bacterial toxins, including all of the clostridial glucosyltransferase toxins and various MARTX toxins. GFP-fusions to these homologous domains are also membrane associated, indicating that this is a conserved membrane localization domain (MLD). We have identified three residues (Y23, S68, R70) as necessary for proper localization of one but not all MLDs. In addition, we found that substitution of the RID MLD with the MLDs from two different effector domains from the Vibrio vulnificus MARTX toxin restored RID activity, indicating that there is functional overlap between these MLDs. This study describes the initial recognition of a family of conserved plasma membrane-targeting domains found in multiple large bacterial toxins.