title: Hit the right spots: cell cycle control by phosphorylated guanosines in alphaproteobacteria.
abstract: The class Alphaproteobacteria includes Gram-negative free-living, symbiotic and obligate intracellular bacteria, as well as important plant, animal and human pathogens. Recent work has established the key antagonistic roles that phosphorylated guanosines, cyclic-di-GMP (c-di-GMP) and the alarmones guanosine tetraphosphate and guanosine pentaphosphate (collectively referred to as (p)ppGpp), have in the regulation of the cell cycle in these bacteria. In this Review, we discuss the insights that have been gained into the regulation of the initiation of DNA replication and cytokinesis by these second messengers, with a particular focus on the cell cycle of Caulobacter crescentus. We explore how the fluctuating levels of c-di-GMP and (p)ppGpp during the progression of the cell cycle and under conditions of stress control the synthesis and proteolysis of key regulators of the cell cycle. As these signals also promote bacterial interactions with host cells, the enzymes that control (p)ppGpp and c-di-GMP are attractive antibacterial targets.
authors.affiliation: Bacterial Cell cycle and Development (BCcD), Unité de recherche en biologie des micro-organismes (URBM), University of Namur, 61 Rue de Bruxelles, Namur 5000, Belgium.
authors.forename: Régis
authors.initials: R
authors.lastname: Hallez
authors.affiliation: Department of Microbiology and Molecular Medicine, Institute of Genetics &Genomics in Geneva (iGE3), Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland.
authors.forename: Marie
authors.initials: M
authors.lastname: Delaby
authors.affiliation: Department of Microbiology and Molecular Medicine, Institute of Genetics &Genomics in Geneva (iGE3), Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland.|Present address: Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands.
authors.forename: Stefano
authors.initials: S
authors.lastname: Sanselicio
authors.affiliation: Department of Microbiology and Molecular Medicine, Institute of Genetics &Genomics in Geneva (iGE3), Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland.
authors.forename: Patrick H
authors.initials: PH
authors.lastname: Viollier
mesh_terms: D016935:Caulobacter crescentus / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology; D059447:Cell Cycle Checkpoints / Q000502:physiology*; D002455:Cell Division; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000378:metabolism; D048749:Cytokinesis / Q000502:physiology; D004261:DNA Replication / Q000502:physiology; D015964:Gene Expression Regulation, Bacterial; D006158:Guanosine Pentaphosphate / Q000378:metabolism*; D006159:Guanosine Tetraphosphate / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology; D016962:Sinorhizobium meliloti / Q000378:metabolism*
chemical_list: D006159:Guanosine Tetraphosphate; D006158:Guanosine Pentaphosphate; C062025:bis(3',5')-cyclic diguanylic acid; D006152:Cyclic GMP