Interface switch mediates signal transmission in a two-component system.
Interface switch mediates signal transmission in a two-component system.
复制标题
接口开关介导二元系统中的信号传输。
DOI：
10.1073/pnas.1912080117
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发表时间：
2020
影响因子：
11.1
通讯作者：
Tao Yuyong
中科院分区：
文献类型：
--
作者：
Wang Mingxing;Guo Qiong;Zhu Kongfu;Fang Bo;Yang Yifan;Teng Maikun;Li Xu;Tao Yuyong
为了适应不断变化的环境，细菌必须迅速将胞外信息转化为适当的细胞反应途径。由膜嵌入的组氨酸激酶（HK）和细胞质反应调节剂组成的双组分系统通常执行此功能。在这项工作中，我们提出的结构和功能数据显示，HptRSA，G6 P传感器从金黄色葡萄球菌，经历构象变化后，G6 P与HptA的结合，导致它切换其接口与HptS的周质结构域。结果，HK的周质侧发生旋转和闭合。这种以前未报道的激活模式不仅扩展了我们对激酶激活中HK信号感知的理解，而且为设计新的抗微生物药物提供了框架。双组分系统（TCS）是原核细胞中将环境刺激信号转导至细胞反应通路的主要信号蛋白，通常由膜包埋的组氨酸激酶和细胞质反应调节因子组成。HptRSA是最近鉴定的TCS，由G6 P相关传感蛋白（HptA）、跨膜组氨酸激酶（HptS）和胞质效应子（HptR）组成。HptRSA介导葡萄糖-6-磷酸（G6 P）摄取以支持金黄色葡萄球菌在各种宿主细胞内生长和增殖。HptRSA如何感知G6 P并触发下游反应的机制仍然难以捉摸。在这里，我们解决了在apo和G6 P结合状态下的HptA结构。G6 P结合在两个HptA结构域之间的裂缝引起的构象关闭运动。与HptS的周质结构域复合的HptA的解析结构表明，HptA通过组成型和可切换界面与HptS相互作用。HptA的G6 P游离形式结合到HptS周质结构域（HptSp）的膜远端侧，导致HptSp原聚体对的平行构象。然而，一旦HptA与G6 P结合，其分子内结构域闭合将HptA-HptSp接触区切换到近膜结构域，这导致每个HptSp原聚体的C末端旋转和闭合。通过对HptA和HptS突变体的生化和生长测定，我们提出了一种独特的界面开关介导的信号转导机制。我们的研究结果为细菌营养感测提供了机制性的见解，并扩展了我们对TCS传达外部信号的激活模式的理解。
Significance To adapt to the changing environment, bacteria must quickly transduce extracellular information into appropriate cellular response pathways. Two-component systems consisting of a membrane-embedded histidine kinase (HK) and a cytoplasmic response regulator often perform this function. In this work, we present structural and functional data showing that HptRSA, a G6P sensor from Staphylococcus aureus, undergoes conformational changes after G6P binding with HptA that causes it to switch its interface with the periplasmic domain of HptS. As a result, a rotation and closure occur in the periplasmic side of the HK. This previously unreported mode of activation not only expands our understanding of HK signal perception in kinase activation but also provides a framework for designing new antimicrobial drugs. Two-component systems (TCS), which typically consist of a membrane-embedded histidine kinase and a cytoplasmic response regulator, are the dominant signaling proteins for transduction of environmental stimuli into cellular response pathways in prokaryotic cells. HptRSA is a recently identified TCS consisting of the G6P-associated sensor protein (HptA), transmembrane histidine kinase (HptS), and cytoplasmic effector (HptR). HptRSA mediates glucose-6-phosphate (G6P) uptake to support Staphylococcus aureus growth and multiplication within various host cells. How the mechanism by which HptRSA perceives G6P and triggers a downstream response has remained elusive. Here, we solved the HptA structures in apo and G6P-bound states. G6P binding in the cleft between two HptA domains caused a conformational closing movement. The solved structures of HptA in complex with the periplasmic domain of HptS showed that HptA interacts with HptS through both constitutive and switchable interfaces. The G6P-free form of HptA binds to the membrane-distal side of the HptS periplasmic domain (HptSp), resulting in a parallel conformation of the HptSp protomer pair. However, once HptA associates with G6P, its intramolecular domain closure switches the HptA-HptSp contact region into the membrane-proximal domain, which causes rotation and closure of the C termini of each HptSp protomer. Through biochemical and growth assays of HptA and HptS mutant variants, we proposed a distinct mechanism of interface switch-mediated signaling transduction. Our results provide mechanistic insights into bacterial nutrient sensing and expand our understanding of the activation modes by which TCS communicates external signals.