Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China.
Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, Zhejiang, 310014, China.
Mol Microbiol. 2018 Nov;110(4):648-661. doi: 10.1111/mmi.14122. Epub 2018 Oct 15.
Phosphate concentration extensively modulates the central physiological processes mediated by the two-component system PhoR-PhoP in actinobacteria. The system serves a role beyond phosphate metabolism, mediating crucial functions in nitrogen and carbon metabolism, and secondary metabolism in response to the nutritional states. Here, we found that the phosphate-sensing regulator PhoP was propionylated, and thus lost its DNA-binding activity in vivo and in vitro in Saccharopolyspora erythraea. Two key conserved lysine residues 198 and 203 (K198 and K203) in winged HTH motif at the C-terminal domain of PhoP are propionylated by protein acyltransferase AcuA (encoding by sace_5148). Single amino acid mutation of these two lysine residues resulted in severely impaired binding of PhoP to PHO box. The addition of propionate (to supply precursors for erythromycin biosynthesis) increases the intracellular propionylation level of PhoP, resulting in the loss of response to phosphate availability. Furthermore, simultaneous mutation of K198 and K203 of PhoP to arginine, mimicking the non-propionylated form, promotes the expression of the PhoP regulon under the condition of propionate addition. Together, these findings present a common regulatory mechanism of genes' expression mediated by posttranslational regulation of OmpR family transcriptional regulator PhoP and provide new insights into the multifaceted regulation of metabolism in response to nutritional signals.
磷酸盐浓度广泛调节了放线菌中二组分系统 PhoR-PhoP 介导的核心生理过程。该系统的作用超出了磷酸盐代谢范围，在氮和碳代谢以及次级代谢中对营养状态的响应中发挥着重要作用。在这里，我们发现磷酸盐感应调节因子 PhoP 发生了丙酰化，从而使其在体内和体外丧失了 DNA 结合活性。PhoP 蛋白 C 端结构域 Winged HTH 模体中的两个关键保守赖氨酸残基 198 和 203（K198 和 K203）被蛋白酰基转移酶 AcuA（由 sace_5148 编码）丙酰化。这两个赖氨酸残基的单个氨基酸突变导致 PhoP 与 PHO 盒的结合严重受损。丙酸盐（为红霉素生物合成提供前体）的添加增加了 PhoP 的细胞内丙酰化水平，导致对磷酸盐可用性的反应丧失。此外，PhoP 的 K198 和 K203 同时突变为精氨酸，模拟非丙酰化形式，在添加丙酸盐的条件下促进 PhoP 调节子的表达。总之，这些发现揭示了 OmpR 家族转录调节因子 PhoP 介导的基因表达的一种常见的翻译后调控机制，并为营养信号响应中代谢的多方面调控提供了新的见解。
