Cyclic‐di‐AMP synthesis by the diadenylate cyclase CdaA is modulated by the peptidoglycan biosynthesis enzyme GlmM in Lactococcus lactis. Issue 6 (15th December 2015)

• Record Type: Journal Article
• Authors: Zhu, Yan; Pham, Thi Huong; Nhiep, Thi Hanh Nguyen; Vu, Ngoc Minh Thu; Marcellin, Esteban; Chakrabortti, Alolika; Wang, Yuanliang; Waanders, Jennifer; Lo, Raquel; Huston, Wilhelmina M.; Bansal, Nidhi; Nielsen, Lars K.; Liang, Zhao‐Xun; Turner, Mark S.
• Is Part Of: Molecular microbiology. Volume 99:Issue 6(2016)
• Page Start: 1015
• Page End: 1027
• Publication Date: 2015-12-15
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.13281
• Languages: English
• ISSNs: 0950-382X

Abstract

Summary: The second messenger cyclic‐di‐adenosine monophosphate (c‐di‐AMP) plays important roles in growth, virulence, cell wall homeostasis, potassium transport and affects resistance to antibiotics, heat and osmotic stress. Most Firmicutes contain only one c‐di‐AMP synthesizing diadenylate cyclase (CdaA); however, little is known about signals and effectors controlling CdaA activity and c‐di‐AMP levels. In this study, a genetic screen was employed to identify components which affect the c‐di‐AMP level in L actococcus . We characterized suppressor mutations that restored osmoresistance to spontaneous c‐di‐AMP phosphodiesterase gdp P mutants, which contain high c‐di‐AMP levels. Loss‐of‐function and gain‐of‐function mutations were identified in the cda A and gdp P genes, respectively, which led to lower c‐di‐AMP levels. A mutation was also identified in the phosphoglucosamine mutase gene glm M, which is commonly located within the cda A operon in bacteria. The glm M I154F mutation resulted in a lowering of the c‐di‐AMP level and a reduction in the key peptidoglycan precursor UDP‐N‐acetylglucosamine in L . lactis . C‐di‐AMP synthesis by CdaA was shown to be inhibited by GlmM I154F more than GlmM and GlmM I154F was found to bind more strongly to CdaA than GlmM. These findings identify GlmM as a c‐di‐AMP level modulating protein and provide a direct connection between c‐di‐AMP synthesis and peptidoglycan biosynthesis. Abstract : c‐di‐AMP is an essential signalling molecule which affects peptidoglycan homeostasis and resistance against various stressors, however little is known regarding how the c‐di‐AMP level is regulated in the cell. Here we identify the peptidoglycan biosynthesis enzyme GlmM as a modulator of c‐di‐AMP synthesis through its regulation of diadenylate cyclase enzyme CdaA activity in Lactococcus lactis .