Cell-cell signal-dependent dynamic interactions between HD-GYP and GGDEF domain proteins mediate virulence in Xanthomonas campestris
Cell-cell signal-dependent dynamic interactions between HD-GYP and GGDEF domain proteins mediate virulence in Xanthomonas campestris
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DOI：
10.1073/pnas.0912839107
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发表时间：
2010-03-30
影响因子：
11.1
通讯作者：
Dow, J. Maxwell
中科院分区：
文献类型：
--
作者：
Ryan, Robert P.;McCarthy, Yvonne;Dow, J. Maxwell
RpfG 是一类广泛存在的细菌双组分调节剂的范例，其具有连接到组氨酸-天冬氨酸-甘氨酸-酪氨酸-脯氨酸 (HD-GYP) 环二 GMP 磷酸二酯酶结构域的 CheY 样接收结构域。在植物病原体中，野油菜黄单胞菌 pv。 Campestris (Xcc) 是一种由 RpfG 和复合传感器激酶 RpfC 组成的双组分系统，参与传感和响应扩散信号因子 (DSF)，这对于细胞间信号传导至关重要。 RpfF参与DSF的合成，rpfF、rpfG或rpfC的突变导致胞外酶、生物膜结构和运动性等毒力因子的合成协同减少。使用酵母双杂交分析和 Xcc 中的荧光共振能量转移实验，我们表明 RpfG 与具有二鸟苷酸环化酶 (GGDEF) 结构域的两种蛋白质的物理相互作用控制着 RpfG 调节的毒力功能的子集。 RpfG 相互作用通过 HD-GYP 结构域中保守 GYP 基序的三个残基的丙氨酸取代而消除。改变 GYP 基序或删除两个 GGDEF 结构域蛋白会降低 Xcc 运动性，但不会降低细胞外酶的合成或生物膜的形成。 RpfG-GGDEF 相互作用是动态的，依赖于 DSF 信号传导，在 rpfF 突变体中减少，但通过添加 DSF 恢复。结果与模型一致，其中控制运动的 DSF 信号转导依赖于影响环二 GMP 局部表达的蛋白质的高度调节的动态相互作用。
RpfG is a paradigm for a class of widespread bacterial two-component regulators with a CheY-like receiver domain attached to a histidine-aspartic acid-glycine-tyrosine-proline (HD-GYP) cyclic di-GMP phosphodiesterase domain. In the plant pathogen Xanthomonas campestris pv. campestris (Xcc), a two-component system comprising RpfG and the complex sensor kinase RpfC is implicated in sensing and responding to the diffusible signaling factor (DSF), which is essential for cell-cell signaling. RpfF is involved in synthesizing DSF, and mutations of rpfF, rpfG, or rpfC lead to a coordinate reduction in the synthesis of virulence factors such as extracellular enzymes, biofilm structure, and motility. Using yeast two-hybrid analysis and fluorescence resonance energy transfer experiments in Xcc, we show that the physical interaction of RpfG with two proteins with diguanylate cyclase (GGDEF) domains controls a subset of RpfG-regulated virulence functions. RpfG interactions were abolished by alanine substitutions of the three residues of the conserved GYP motif in the HD-GYP domain. Changing the GYP motif or deletion of the two GGDEF-domain proteins reduced Xcc motility but not the synthesis of extracellular enzymes or biofilm formation. RpfG-GGDEF interactions are dynamic and depend on DSF signaling, being reduced in the rpfF mutant but restored by DSF addition. The results are consistent with a model in which DSF signal transduction controlling motility depends on a highly regulated, dynamic interaction of proteins that influence the localized expression of cyclic di-GMP.