DgrA is a member of a new family of cyclic diguanosine monophosphate receptors and controls flagellar motor function in Caulobacter crescentus

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 104; no. 10; pp. 4112 - 4117
• Main Authors: Christen, Matthias, Christen, Beat, Allan, Martin G, Folcher, Marc, Jenö, Paul, Grzesiek, Stephan, Jenal, Urs
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 06.03.2007; National Acad Sciences
• Subjects: Amino Acid Sequence; Bacteria; Bacterial Proteins - genetics; Bacterial Proteins - physiology; Bacteriology; Biochemistry; Biological Sciences; Carrier Proteins - genetics; Carrier Proteins - physiology; Caulobacter crescentus; Caulobacter crescentus - metabolism; Cell adhesion & migration; Cell motility; Cell Movement; Cells; Chemical equilibrium; Chromatography, Affinity; Cross-Linking Reagents - pharmacology; Cyclic GMP - analogs & derivatives; Cyclic GMP - metabolism; Escherichia coli - metabolism; Flagella; Flagella - metabolism; Intracellular Signaling Peptides and Proteins - genetics; Intracellular Signaling Peptides and Proteins - physiology; Ligands; Magnetic Resonance Spectroscopy; Models, Molecular; Molecular Sequence Data; Motor ability; Plasmids; Protein Conformation; Proteins; Pseudomonas aeruginosa; Pseudomonas aeruginosa - metabolism; Receptors; Salmonella typhimurium; Salmonella typhimurium - metabolism; Ultraviolet Rays
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0607738104

Bacteria are able to switch between two mutually exclusive lifestyles, motile single cells and sedentary multicellular communities that colonize surfaces. These behavioral changes contribute to an increased fitness in structured environments and are controlled by the ubiquitous bacterial second messenger cyclic diguanosine monophosphate (c-di-GMP). In response to changing environments, fluctuating levels of c-di-GMP inversely regulate cell motility and cell surface adhesins. Although the synthesis and breakdown of c-di-GMP has been studied in detail, little is known about the downstream effector mechanisms. Using affinity chromatography, we have isolated several c-di-GMP-binding proteins from Caulobacter crescentus. One of these proteins, DgrA, is a PilZ homolog involved in mediating c-di-GMP-dependent control of C. crescentus cell motility. Biochemical and structural analysis of DgrA and homologs from C. crescentus, Salmonella typhimurium, and Pseudomonas aeruginosa demonstrated that this protein family represents a class of specific diguanylate receptors and suggested a general mechanism for c-di-GMP binding and signal transduction. Increased concentrations of c-di-GMP or DgrA blocked motility in C. crescentus by interfering with motor function rather than flagellar assembly. We present preliminary evidence implicating the flagellar motor protein FliL in DgrA-dependent cell motility control.