Institut Pasteur, Université Paris Cité, Department of Microbiology, Biology of Gram-Positive Pathogens, Paris, France.
University of Messina, Department of Human Pathology, Messina, Italy.
Nat Commun. 2024 Oct 24;15(1):9175. doi: 10.1038/s41467-024-53439-3.
Bacterial two-component systems (TCSs) are signaling modules that control physiology, adaptation, and host interactions. A typical TCS consists of a histidine kinase (HK) that activates a response regulator via phosphorylation in response to environmental signals. Here, we systematically test the effect of inactivating the conserved phosphatase activity of HKs to activate TCS signaling pathways. Transcriptome analyses of 14 HK mutants in Streptococcus agalactiae, the leading cause of neonatal meningitis, validate the conserved HK phosphatase mechanism and its role in the inhibition of TCS activity in vivo. Constitutive TCS activation, independent of environmental signals, enables high-resolution mapping of the regulons for several TCSs (e.g., SaeRS, BceRS, VncRS, DltRS, HK11030, HK02290) and reveals the functional diversity of TCS signaling pathways, ranging from highly specialized to interconnected global regulatory networks. Targeted analysis shows that the SaeRS-regulated PbsP adhesin acts as a signaling molecule to activate CovRS signaling, thereby linking the major regulators of host-pathogen interactions. Furthermore, constitutive BceRS activation reveals drug-independent activity, suggesting a role in cell envelope homeostasis beyond antimicrobial resistance. This study highlights the versatility of constitutive TCS activation, via phosphatase-deficient HKs, to uncover regulatory networks and biological processes.
细菌双组分系统（TCS）是控制生理、适应和宿主相互作用的信号模块。典型的 TCS 由组氨酸激酶（HK）组成，该激酶通过磷酸化响应环境信号激活响应调节剂。在这里，我们系统地测试了失活 HK 的保守磷酸酶活性以激活 TCS 信号通路的效果。14 种无乳链球菌（导致新生儿脑膜炎的主要原因）中 HK 突变体的转录组分析验证了保守的 HK 磷酸酶机制及其在体内抑制 TCS 活性中的作用。不依赖环境信号的组成型 TCS 激活能够对几个 TCS（例如 SaeRS、BceRS、VncRS、DltRS、HK11030、HK02290）的调控组进行高分辨率映射，并揭示 TCS 信号通路的功能多样性，从高度专业化到相互连接的全局调控网络。靶向分析表明，SaeRS 调节的 PbsP 粘附素作为一种信号分子激活 CovRS 信号，从而将宿主-病原体相互作用的主要调节剂联系起来。此外，组成型 BceRS 激活揭示了独立于药物的活性，表明其在细胞包膜稳态中的作用超出了抗菌药物耐药性。这项研究强调了通过缺乏磷酸酶的 HK 进行组成型 TCS 激活以揭示调控网络和生物学过程的多功能性。
