Opposing pairs of serine protein kinases and phosphatases transmit signals of environmental stress to activate a bacterial transcription factor

• Published in: Genes & development Vol. 10; no. 18; pp. 2265 - 2275
• Main Authors: Yang, X, Kang, C M, Brody, M S, Price, C W
• Format: Journal Article
• Language: English
• Published: United States 15.09.1996
• Subjects: Bacillus subtilis - metabolism; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Binding Sites; Carrier Proteins - metabolism; DNA-Binding Proteins; Enzyme Activation; Escherichia coli Proteins; Molecular Sequence Data; Phosphoric Monoester Hydrolases - metabolism; Phosphorylation; Sigma Factor - genetics; Sigma Factor - metabolism; Signal Transduction; Substrate Specificity; Transcription Factors - metabolism
• ISSN: 0890-9369; 1549-5477
• DOI: 10.1101/gad.10.18.2265

The general stress response of the bacterium Bacillus subtilis is governed by a signal transduction network that regulates activity of the sigma(B) transcription factor. We show that this network comprises two partner-switching modules, RsbX-RsbS-RsbT and RsbU-RsbV-RsbW, which contribute to regulating sigma(B). Each module consists of a phosphatase (X or U), an antagonist protein (S or V), and a switch protein/kinase (T or W). In the downstream module, the W anti-sigma factor is the primary regulator of sigma(B) activity. If the V antagonist is phosphorylated, the W switch protein binds and inhibits sigma(B). If V is unphosphorylated, it complexes W, freeing sigma(B) to interact with RNA polymerase and promote transcription. The phosphorylation state of V is controlled by opposing kinase (W) and phosphatase (U) activities. The U phosphatase is regulated by the upstream module. The T switch protein directly binds U, stimulating phosphatase activity. The T-U interaction is governed by the phosphorylation state of the S antagonist, controlled by opposing kinase (T) and phosphatase (X) activities. This partner-switching mechanism provides a general regulatory strategy in which linked modules sense and integrate multiple signals by protein-protein interaction.