The EAL domain protein YciR acts as a trigger enzyme in a c-di-GMP signalling cascade in E. coli biofilm control

• Sandra Lindenberg ^[1] ; Gisela Klauck ^[1] ; Christina Pesavento ^[1] ; Eberhard Klauck ^[1] ; Regine Hengge ^[1]
  1. [1] Institut für Biologie—Mikrobiologie, Freie Universität Berlin, Berlin, Germany
• Localización: EMBO journal: European Molecular Biology Organization, ISSN 0261-4189, Vol. 32, Nº. 14, 2013, págs. 2001-2014
• Idioma: inglés
• Enlaces
  • Texto completo
• Resumen

  • C-di-GMP—which is produced by diguanylate cyclases (DGC) and degraded by specific phosphodiesterases (PDEs)—is a ubiquitous second messenger in bacterial biofilm formation. In Escherichia coli, several DGCs (YegE, YdaM) and PDEs (YhjH, YciR) and the MerR-like transcription factor MlrA regulate the transcription of csgD, which encodes a biofilm regulator essential for producing amyloid curli fibres of the biofilm matrix. Here, we demonstrate that this system operates as a signalling cascade, in which c-di-GMP controlled by the DGC/PDE pair YegE/YhjH (module I) regulates the activity of the YdaM/YciR pair (module II). Via multiple direct interactions, the two module II proteins form a signalling complex with MlrA. YciR acts as a connector between modules I and II and functions as a trigger enzyme: its direct inhibition of the DGC YdaM is relieved when it binds and degrades c-di-GMP generated by module I. As a consequence, YdaM then generates c-di-GMP and—by direct and specific interaction—activates MlrA to stimulate csgD transcription. Trigger enzymes may represent a general principle in local c-di-GMP signalling.