HrpB7 from Xanthomonas campestris pv. vesicatoria is an essential component of the type III secretion system and shares features of HrpO/FliJ/YscO family members
HrpB7 from Xanthomonas campestris pv. vesicatoria is an essential component of the type III secretion system and shares features of HrpO/FliJ/YscO family members
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DOI：
10.1111/cmi.13160
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发表时间：
2020-03-03
影响因子：
3.4
通讯作者：
Buettner, Daniela
中科院分区：
文献类型：
--
作者：
Drehkopf, Sabine;Otten, Christian;Buettner, Daniela
革兰氏阴性杆菌野油菜黄单胞菌。水泡菌通过III型分泌系统(T3SS)将效应蛋白转运到真核细胞中。T3SS跨越两个细菌膜，由20多个蛋白质组成，其中9个蛋白质在动植物病原体中保守，构成分泌器官的核心亚单位。野油菜X.campestris pv.膀胱吞噬作用还依赖于功能未知的非保守蛋白，包括HrpB7，它包含预测的N-末端和C-末端盘绕区域。在本研究中，我们提供了HrpB7形成稳定的寡聚络合物的实验证据。相互作用和定位研究表明，HrpB7与T3SS的内膜和预测的细胞质(C)环成分相互作用，但对于C环的组装是必不可少的。HrpB7的其他相互作用伙伴包括细胞质三磷酸腺苷酶HrcN和T3S伴侣HpaB。HrpB7与T3SS组分的相互作用以及HrpB7形成的络合物取决于亮氨酸七肽基序的存在，这些基序是预测的N-末端和C-末端卷曲结构的一部分。我们的数据表明，HrpB7形成了与T3SS相关的多聚体复合体，并可能作为一般T3S伴侣HpaB的对接位置。
The Gram-negative bacterium Xanthomonas campestris pv. vesicatoria translocates effector proteins via a type III secretion system (T3SS) into eukaryotic cells. The T3SS spans both bacterial membranes and consists of more than 20 proteins, 9 of which are conserved in plant and animal pathogens and constitute the core subunits of the secretion apparatus. T3S in X. campestris pv. vesicatoria also depends on nonconserved proteins with yet unknown function including HrpB7, which contains predicted N- and C-terminal coiled-coil regions. In the present study, we provide experimental evidence that HrpB7 forms stable oligomeric complexes. Interaction and localisation studies suggest that HrpB7 interacts with inner membrane and predicted cytoplasmic (C) ring components of the T3SS but is dispensable for the assembly of the C ring. Additional interaction partners of HrpB7 include the cytoplasmic adenosinetriphosphatase HrcN and the T3S chaperone HpaB. The interaction of HrpB7 with T3SS components as well as complex formation by HrpB7 depends on the presence of leucine heptad motifs, which are part of the predicted N- and C-terminal coiled-coil structures. Our data suggest that HrpB7 forms multimeric complexes that associate with the T3SS and might serve as a docking site for the general T3S chaperone HpaB.