Infection and Immunity
9 (Article e 00347)
The signaling molecule cyclic diguanylate (c-di-GMP) mediates physiological adaptation to extracellular stimuli in a wide range of bacteria. The complex metabolic pathways governing c-di-GMP synthesis and degradation are highly regulated, but the specific cues that impact c-di-GMP signaling are largely unknown. In the intestinal pathogen Clostridium difficile, c-di-GMP inhibits flagellar motility and toxin production and promotes pilus-dependent biofilm formation, but no specific biological functions have been ascribed to any of the individual c-di-GMP synthases or phosphodiesterases (PDEs). Here, we report the functional and biochemical characterization of a c-di-GMP PDE, PdcA, 1 of 37 confirmed or putative c-di-GMP metabolism proteins in C. difficile 630. Our studies reveal that pdcA transcription is controlled by the nutrient-regulated transcriptional regulator CodY and accordingly increases during stationary phase. In addition, PdcA PDE activity is allosterically regulated by GTP, further linking c-di-GMP levels to nutrient availability. Mutation of pdcA increased biofilm formation and reduced toxin biosynthesis without affecting swimming motility or global intracellular c-di-GMP. Analysis of the transcriptional response to pdcA mutation indicates that PdcA-dependent phenotypes manifest during stationary phase, consistent with regulation by CodY. These results demonstrate that inactivation of this single PDE gene is sufficient to impact multiple c-di-GMP-dependent phenotypes, including the production of major virulence factors, and suggest a link between c-di-GMP signaling and nutrient availability.
Original Publication Citation
Purcell, E. B., McKee, R. W., Courson, D. S., Garrett, E. M., McBride, S. M., Cheney, R. E., & Tamayo, R. (2017). A nutrient-regulated cyclic diguanylate phosphodiesterase controls Clostridium difficile biofilm and toxin production during stationary phase. Infection and Immunity, 85(9 (Article e00347)), 1-17. doi:10.1128/IAI.00347-17
0000-0002-3745-3316 (Rita Tamayo)
Purcell, Erin B.; McKee, Robert W.; Courson, David S.; Garrett, Elizabeth M.; McBride, Shonna M.; Cheney, Richard E.; and Tamayo, Rita, "A Nutrient-Regulated Cyclic Diguanylate Phosphodiesterase Controls Clostridium difficile Biofilm and Toxin Production During Stationary Phase" (2017). Chemistry & Biochemistry Faculty Publications. 92.