Phosphorylation signalling through the Legionella quorum sensing histidine kinases LqsS and LqsT converges on the response regulator LqsR
Phosphorylation signalling through the Legionella quorum sensing histidine kinases LqsS and LqsT converges on the response regulator LqsR
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DOI：
10.1111/mmi.12612
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发表时间：
2014-06
影响因子：
3.6
通讯作者：
U. Schell;A. Kessler;H. Hilbi
中科院分区：
文献类型：
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作者：
U. Schell;A. Kessler;H. Hilbi
嗜肺军团菌是军团病的病原体，军团病是一种危及生命的肺炎。对于细胞间的交流，细菌使用自诱导剂LAI‐1(3‐羟基戊烷‐4‐1)，该诱导剂由Lqs（军团菌群体感应）系统产生和检测。该系统包括自诱导合成酶LqsA，假定的传感器激酶LqsS和LqsT，以及原型响应调节器LqsR。Lqs调节的过程包括嗜肺乳杆菌与吞噬细胞的相互作用、细胞外细丝的产生和自然能力。通过生化方法，我们发现LqsS和LqsT在细胞质组氨酸激酶结构域的一个保守的组氨酸残基（H200或H204）上被[γ‐32P]‐ATP自磷酸化。Pull - down实验显示LqsS和LqsT被LqsR或phospho - LqsR结合。依赖于保守的接收器结构域天冬氨酸（D108），响应调节因子通过催化磷酸化- LqsS或磷酸化- LqsT的去磷酸化来阻止两种传感器激酶的自磷酸化。此外，LqsR在D108位点被乙酰-磷酸或磷酸- LqsT磷酸化后形成二聚体。最后，在大肠杆菌中异种生产时，LqsT（而不是LqsS）被ATP自磷酸化，LqsR通过催化磷酸- LqsT的去磷酸化来阻止自磷酸化。综上所述，这些结果表明，通过军团菌群体感应组氨酸激酶LqsS和LqsT进行的磷酸化信号传导会向反应调节因子LqsR聚集。
The environmental bacterium Legionella pneumophila is the causative agent of Legionnaires' disease, a life‐threatening pneumonia. For cell–cell communication the bacteria employ the autoinducer LAI‐1 (3‐hydroxypentadecane‐4‐one), which is produced and detected by the Lqs (Legionella quorum sensing) system. The system comprises the autoinducer synthase LqsA, the putative sensor kinases LqsS and LqsT, and the prototypic response regulator LqsR. Lqs‐regulated processes include L. pneumophila‐phagocyte interactions, production of extracellular filaments, and natural competence. Using biochemical approaches we show here that LqsS and LqsT are autophosphorylated by [γ‐32P]‐ATP at a conserved histidine residue (H200 or H204) located in their cytoplasmic histidine kinase domain. Pull‐down assays revealed that LqsS and LqsT are bound by LqsR or phospho‐LqsR. Dependent on the conserved receiver domain aspartate (D108), the response regulator prevented autophosphorylation of both sensor kinases by catalysing the dephosphorylation of phospho‐LqsS or phospho‐LqsT. Moreover, LqsR formed dimers upon phosphorylation at D108 by either acetyl‐phosphate or phospho‐LqsT. Finally, upon heterologous production in Escherichia coli, LqsT (but not LqsS) was autophosphorylated by ATP, and LqsR prevented the autophosphorylation by catalysing the dephosphorylation of phospho‐LqsT. In summary, these results indicate that phosphorylation signalling through the Legionella quorum sensing histidine kinases LqsS and LqsT converges on the response regulator LqsR.