Second messenger signaling in Clostridioides difficile

• Published in: Current opinion in microbiology 2022-02, Vol.65, p.138-144
• Main Author: Purcell, Erin B.
• Format: Article
• Language: English
• Subjects: Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Clostridioides; Clostridioides difficile - genetics; Gene Expression Regulation, Bacterial; Nucleotides; Second Messenger Systems - physiology
• ISSN: 1369-5274; 1879-0364
• DOI: 10.1016/j.mib.2021.11.006

•Metabolism of c-di-GMP, c-di-AMP, and pGpp has been confirmed in Clostridioides difficile.•c-di-GMP signaling is accomplished via two classes of riboswitch and indirect control of the transcription factor SigD.•c-diAMP signaling involves protein effectors, including a transcriptional regulator, a sensor kinase, and a potassium transport protein.•The mechanisms of pGpp signaling in this organism are unknown.•Nucleotide signaling feedback loops are common and thus far have been identified for c-di-GMP in C. difficile. Small, diffusible second messenger molecules transmit information about extracellular conditions to intracellular machinery in order to influence transcription, translation, and metabolism. The enteropathogenic bacterium Clostridioides difficile coordinates its response to a dynamic and hostile environment via nucleotide second messengers. While riboswitch-mediated cyclic diguanylate regulation has been extensively characterized in C. difficile, signaling by cyclic diadenylate and by guanosine alarmones has only recently been confirmed in this organism. This review summarizes the current knowledge of how nucleotide second messenger signaling regulates physiological processes in C. difficile.