RESUMO
The hybrid sensor kinase BarA and its cognate response regulator UvrY, members of the two-component signal transduction family, activate transcription of CsrB and CsrC noncoding RNAs. These two small RNAs act by sequestering the RNA binding protein CsrA, which posttranscriptionally regulates translation and/or stability of its target mRNAs. Here, we provide evidence that CsrA positively affects, although indirectly, uvrY expression, at both the transcriptional and translational levels. We also demonstrate that CsrA is required for properly switching BarA from its phosphatase to its kinase activity. Thus, the existence of a feedback loop mechanism that involves the Csr and BarA/UvrY global regulatory systems is exposed.
Assuntos
Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , Proteínas de Membrana/genética , Fosfotransferases/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas Repressoras/metabolismo , Fatores de Transcrição/genética , Escherichia coli/enzimologia , Escherichia coli/genética , Proteínas de Membrana/metabolismo , Fosfotransferases/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas Repressoras/genética , Transdução de Sinais , Fatores de Transcrição/metabolismoRESUMO
The two-component signal transduction system (TCS) BarA/UvrY activates transcription of CsrB and CsrC noncoding RNAs, which act by sequestering the RNA-binding global regulatory protein CsrA. Here, we show that the metabolic end products formate and acetate provide a physiological stimulus for this TCS and thus link posttranscriptional regulation by the Csr system to the metabolic state of the cell.