title: Bis-(3'-5')-cyclic dimeric GMP-linked quorum sensing controls swarming in Vibrio parahaemolyticus.
abstract: Movement over and colonization of surfaces are important survival strategies for bacteria, and many find it advantageous to perform these activities as a group, using quorum sensing to sample population size and synchronize behavior. It is puzzling however, that swarming-proficient and virulent strains of Vibrio parahaemolyticus are silenced for the vibrio archetypal pathway of quorum sensing. Here we describe the S-signal, a pheromone that can be communicated between cells in coculture to regulate surface colonization. This signal was harvested in cell-free supernatants and demonstrated to stimulate swarming gene expression at low cell density. The S-signal was generated by the pyridoxal phosphate-dependent aminotransferase ScrA; signal reception required the periplasmic binding protein ScrB and the membrane-bound GGDEF-EAL domain-containing protein ScrC. ScrC is a bifunctional enzyme that has the ability to form and degrade the second messenger bis-(3'-5') cyclic dimeric GMP (c-di-GMP). ScrA in neighboring cells was able to alter the activity of ScrC in a ScrB-dependent manner, transforming ScrC's repressing ability to inducing activity with respect to swarming. Conversely, cell-cell signaling repressed capsule gene expression. In summary, we report that quorum sensing can stimulate swarming in V. parahaemolyticus; it does so via an alternative pathway capable of generating an autoinducing signal that influences c-di-GMP, thereby expanding the lexicon and language of cell-cell communication.
authors: Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA.
authors: Michael J
authors: MJ
authors: Trimble
authors: Linda L
authors: LL
authors: McCarter
mesh_terms: D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000378:metabolism; D005798:Genes, Bacterial; D053038:Quorum Sensing; D015398:Signal Transduction; D014736:Vibrio parahaemolyticus / Q000235:genetics / Q000502:physiology*
chemical_list: C062025:bis(3',5')-cyclic diguanylic acid; D006152:Cyclic GMP