Systematic analysis of cyclic di-GMP signalling enzymes and their role in biofilm formation and virulence in Yersinia pestis.

Cyclic di-GMP (c-di-GMP) is a signalling molecule that governs the transition between planktonic and biofilm states. Previously, we showed that the diguanylate cyclase HmsT and the putative c-di-GMP phosphodiesterase HmsP inversely regulate biofilm formation through control of HmsHFRS-dependent poly-β-1,6-N-acetylglucosamine synthesis. Here, we systematically examine the functionality of the genes encoding putative c-di-GMP metabolic enzymes in Yersinia pestis.

Structure and mechanism of a bacterial light-regulated cyclic nucleotide phosphodiesterase.

The ability to respond to light is crucial for most organisms. BLUF is a recently identified photoreceptor protein domain that senses blue light using a FAD chromophore. BLUF domains are present in various proteins from the Bacteria, Euglenozoa and Fungi.

A staphylococcal GGDEF domain protein regulates biofilm formation independently of cyclic dimeric GMP.

Cyclic dimeric GMP (c-di-GMP) is an important biofilm regulator that allosterically activates enzymes of exopolysaccharide biosynthesis. Proteobacterial genomes usually encode multiple GGDEF domain-containing diguanylate cyclases responsible for c-di-GMP synthesis. In contrast, only one conserved GGDEF domain protein, GdpS (for GGDEF domain protein from Staphylococcus), and a second protein with a highly modified GGDEF domain, GdpP, are present in the sequenced staphylococcal genomes.

The flagellar sigma factor FliA regulates adhesion and invasion of Crohn disease-associated Escherichia coli via a cyclic dimeric GMP-dependent pathway.

The invasion of intestinal epithelial cells by the Crohn disease-associated adherent-invasive Escherichia coli (AIEC) strain LF82 depends on surface appendages, such as type 1 pili and flagella. The absence of flagella in the AIEC strain LF82 results in a concomitant loss of type 1 pili. Here, we show that flagellar regulators, transcriptional activator FlhD(2)C(2), and sigma factor FliA are involved in the coordination of flagellar and type 1 pili synthesis.

An unorthodox bacteriophytochrome from Rhodobacter sphaeroides involved in turnover of the second messenger c-di-GMP.

Bacteriophytochromes are bacterial photoreceptors that sense red/far red light using the biliverdin chromophore. Most bacteriophytochromes work as photoactivated protein kinases. The Rhodobacter sphaeroides bacteriophytochrome BphG1 is unconventional in that it has GGDEF and EAL output domains, which are involved, respectively, in synthesis (diguanylate cyclase) and degradation (phosphodiesterase) of the bacterial second messenger c-di-GMP.

The PilZ domain is a receptor for the second messenger c-di-GMP: the PilZ domain protein YcgR controls motility in enterobacteria.

The ubiquitous bacterial second messenger c-di-GMP controls exopolysaccharide synthesis, flagella- and pili-based motility, gene expression, and interactions of bacteria with eukaryotic hosts. With the exception of bacterial cellulose synthases, the identities of c-di-GMP receptors and end targets have remained unknown. Recently, Amikam and Galperin (Amikam, D.

The ubiquitous protein domain EAL is a cyclic diguanylate-specific phosphodiesterase: enzymatically active and inactive EAL domains.

The EAL domain (also known as domain of unknown function 2 or DUF2) is a ubiquitous signal transduction protein domain in the Bacteria. Its involvement in hydrolysis of the novel second messenger cyclic dimeric GMP (c-di-GMP) was demonstrated in vivo but not in vitro. The EAL domain-containing protein Dos from Escherichia coli was reported to hydrolyze cyclic AMP (cAMP), implying that EAL domains have different substrate specificities.

Cyclic diguanylate is a ubiquitous signaling molecule in bacteria: insights into biochemistry of the GGDEF protein domain.

Proteins containing GGDEF domains are encoded in the majority of sequenced bacterial genomes. In several species, these proteins have been implicated in biosynthesis of exopolysaccharides, formation of biofilms, establishment of a sessile lifestyle, surface motility, and regulation of gene expression. However, biochemical activities of only a few GGDEF domain proteins have been tested.