title: Peptidoglycan perception--sensing bacteria by their common envelope structure.
abstract: Most Eubacteria possess peptidoglycan (PGN) or murein that surrounds the cytoplasmic membrane. While on the one hand this PGN sacculus is a very protective shield that provides resistance to the internal turgor and adverse effects of the environment, it serves on the other hand as a major pattern of recognition due to its unique structure. Eukaryotes harness this particular bacterial macromolecule to perceive (pathogenic) microorganisms and initiate their immune defence. PGN fragments are generated by bacteria as turnover products during bacterial cell wall growth and these fragments can be sensed by plants and animals to assess a potential bacterial threat. To increase the sensitivity the concentration of PGN fragments can be amplified by host hydrolytic enzymes such as lysozyme or amidase. But also bacteria themselves are able to perceive information about the state of their cell wall by sensing small soluble fragments released from its PGN, which eventually leads to the induction of antibiotic responses or cell differentiation. How PGN is sensed by bacteria, plants and animals, and how the antibacterial defence is modulated by PGN perception is the issue of this review.
authors.affiliation: Microbial Genetics, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Ute
authors.initials: U
authors.lastname: Bertsche
authors.affiliation: Microbiology/Biotechnology, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Mayer
authors.affiliation: Microbial Genetics, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Götz
authors.affiliation: Plant Biochemistry, Center for Plant Molecular Biology (ZMBP), University of Tübingen, 72076 Tübingen, Germany. Electronic address: andrea.gust@zmbp.uni-tuebingen.de.
authors.forename: Andrea A
authors.initials: AA
authors.lastname: Gust
mesh_terms: D000818:Animals; D001419:Bacteria / Q000276:immunology* / Q000378:metabolism*; D018407:Bacterial Physiological Phenomena; D002473:Cell Wall / Q000276:immunology* / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D010457:Peptidoglycan / Q000276:immunology* / Q000378:metabolism*; D010944:Plants; D011971:Receptors, Immunologic / Q000378:metabolism*
chemical_list: D010457:Peptidoglycan; D011971:Receptors, Immunologic
keywords: Immune defence; Muropeptide signalling; PAMP; PGN hydrolases; Peptidoglycan