Rhs proteins from diverse bacteria mediate intercellular competition
Rhs proteins from diverse bacteria mediate intercellular competition
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DOI：
10.1073/pnas.1300627110
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发表时间：
2013-04-23
影响因子：
11.1
通讯作者：
Hayes, Christopher S.
中科院分区：
文献类型：
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作者：
Koskiniemi, Sanna;Lamoureux, James G.;Hayes, Christopher S.
重排热点（Rearrangement hotspot, Rhs）及相关的YD-peptide repeat蛋白广泛存在于细菌和真核生物中，但其功能尚不清楚。在这里，我们发现革兰氏阴性Rhs蛋白和来自革兰氏阳性细菌的远亲壁相关蛋白A （WapA）介导细胞间竞争。Rhs和WapA携带多态c末端毒素结构域（Rhs- ct /WapA- ct），用于抑制邻近细胞的生长。这些系统还编码序列多样化的免疫蛋白（RhsI/WapI），特异性中和同源毒素，以保护rhs(+)/wapA（+）细胞免受自身抑制。来自Dickeya dadantii 3937的RhsA和RhsB携带可降解靶细胞DNA的核酸酶结构域。D. dadantii 3937 rhs基因不编码分泌信号序列，但与VI型分泌系统的溶血素协同调节蛋白和缬氨酸重复蛋白G基因相关。缬氨酸-甘氨酸重复蛋白G是抑制细胞功能所必需的，表明Rhs可能通过VI型分泌机制从D. dadantii 3937输出。相比之下，枯草芽孢杆菌菌株的WapA蛋白似乎通过一般分泌途径输出，并将多种tRNase毒素传递到邻近的靶细胞。这些发现表明，来自不同系统发育的细菌的YD-repeat蛋白在接触依赖性生长抑制中具有共同的功能。
Rearrangement hotspot (Rhs) and related YD-peptide repeat proteins are widely distributed in bacteria and eukaryotes, but their functions are poorly understood. Here, we show that Gram-negative Rhs proteins and the distantly related wall-associated protein A (WapA) from Gram-positive bacteria mediate intercellular competition. Rhs and WapA carry polymorphic C-terminal toxin domains (Rhs-CT/WapA-CT), which are deployed to inhibit the growth of neighboring cells. These systems also encode sequence-diverse immunity proteins (RhsI/WapI) that specifically neutralize cognate toxins to protect rhs(+)/wapA(+) cells from autoinhibition. RhsA and RhsB from Dickeya dadantii 3937 carry nuclease domains that degrade target cell DNA. D. dadantii 3937 rhs genes do not encode secretion signal sequences but are linked to hemolysin-coregulated protein and valine-glycine repeat protein G genes from type VI secretion systems. Valine-glycine repeat protein G is required for inhibitor cell function, suggesting that Rhs may be exported from D. dadantii 3937 through a type VI secretion mechanism. In contrast, WapA proteins from Bacillus subtilis strains appear to be exported through the general secretory pathway and deliver a variety of tRNase toxins into neighboring target cells. These findings demonstrate that YD-repeat proteins from phylogenetically diverse bacteria share a common function in contact-dependent growth inhibition.