Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., México.
Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA.
J Biol Chem. 2023 Jun;299(6):104835. doi: 10.1016/j.jbc.2023.104835. Epub 2023 May 17.
The BarA/UvrY two-component signal transduction system mediates adaptive responses of Escherichia coli to changes in growth stage. At late exponential growth phase, the BarA sensor kinase autophosphorylates and transphosphorylates UvrY, which activates transcription of the CsrB and CsrC noncoding RNAs. CsrB and CsrC, in turn, sequester and antagonize the RNA binding protein CsrA, which posttranscriptionally regulates translation and/or stability of its target mRNAs. Here, we provide evidence that during stationary phase of growth, the HflKC complex recruits BarA to the poles of the cells and silences its kinase activity. Moreover, we show that during the exponential phase of growth, CsrA inhibits hflK and hflC expression, thereby enabling BarA activation upon encountering its stimulus. Thus, in addition to temporal control of BarA activity, spatial regulation is demonstrated.
BarA/UvrY 双组分信号转导系统介导大肠杆菌对生长阶段变化的适应性反应。在指数生长后期，BarA 传感器激酶自身磷酸化并将磷酸基团转移给 UvrY，从而激活 CsrB 和 CsrC 非编码 RNA 的转录。CsrB 和 CsrC 反过来结合并拮抗 RNA 结合蛋白 CsrA，后者对其靶 mRNA 的翻译和/或稳定性进行转录后调控。在这里，我们提供的证据表明，在生长的静止期，HflKC 复合物将 BarA 募集到细胞的两极，并使其激酶活性沉默。此外，我们表明，在指数生长阶段，CsrA 抑制 hflK 和 hflC 的表达，从而使 BarA 在遇到其刺激时被激活。因此，除了对 BarA 活性进行时间控制外，还证明了空间调节。
