Porphyromonas gingivalis expresses a limited number of two‐component systems, including RprY, an orphan response regulator which lacks a cognate sensor kinase. In this study, we examined cross‐phosphorylation of RprY on tyrosine residues and its importance for RprY function. We show that RprY reacts with phosphotyrosine antibodies, and found that the tyrosine (Y) residue at position 41 is predicted to be solvent accessible. Loss of RprY increased the level of heterotypic community development with Streptococcus gordonii, and the community‐suppressive function of RprY required Y41. Expression of the Mfa1 fimbrial adhesin was increased in the rprY mutant and in the mutant complemented with rprY containing a Y41F mutation. In a microscale thermophoresis assay, recombinant RprY protein bound to the promoter region of mfa1, and binding was diminished with RprY containing the Y41F substitution. RprY was required for virulence of P. gingivalis in a murine model of alveolar bone loss. Transcriptional profiling indicated that RprY can control the expression of genes encoding the type IX secretion system (T9SS) machinery and virulence factors secreted through the T9SS, including the gingipain proteases and peptidylarginine deiminase (PPAD). Collectively, these results establish the RprY response regulator as a component of the tyrosine phosphorylation regulon in P. gingivalis, which can independently control heterotypic community development through the Mfa1 fimbriae and virulence through the T9SS.

中文翻译：

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RprY 响应调节器在牙龈卟啉单胞菌社区发展和毒力中的作用。

牙龈卟啉单胞菌表达有限数量的双组分系统，包括 RprY，一种缺乏同源传感器激酶的孤儿反应调节剂。在这项研究中，我们检查了 RprY 在酪氨酸残基上的交叉磷酸化及其对 RprY 功能的重要性。我们展示了 RprY 与磷酸酪氨酸抗体反应，并发现 41 位的酪氨酸 (Y) 残基预计可被溶剂使用。RprY 的缺失增加了Streptococcus gordonii的异型群落发展水平，并且 RprY 的群落抑制功能需要 Y41。Mfa1 菌毛粘附素的表达在rprY突变体和与rprY互补的突变体中增加含有 Y41F 突变。在微尺度热泳测定中，重组蛋白RprY结合到启动子区MFA1和结合用含有Y41F取代RprY减少。在牙槽骨丢失的鼠模型中牙龈卟啉单胞菌的毒力需要 RprY 。转录分析表明，RprY 可以控制编码 IX 型分泌系统 (T9SS) 机制的基因的表达，以及通过 T9SS 分泌的毒力因子，包括牙龈蛋白酶和肽基精氨酸脱亚胺酶 (PPAD)。总的来说，这些结果将 RprY 反应调节器确立为牙龈卟啉单胞菌酪氨酸磷酸化调节子的一个组成部分, 可以通过 Mfa1 菌毛独立控制异型群落发展，通过 T9SS 控制毒力。