title: Bacterial autolysins trim cell surface peptidoglycan to prevent detection by the Drosophila innate immune system.
abstract: Bacteria have to avoid recognition by the host immune system in order to establish a successful infection. Peptidoglycan, the principal constituent of virtually all bacterial surfaces, is a specific molecular signature recognized by dedicated host receptors, present in animals and plants, which trigger an immune response. Here we report that autolysins from Gram-positive pathogenic bacteria, enzymes capable of hydrolyzing peptidoglycan, have a major role in concealing this inflammatory molecule from Drosophila peptidoglycan recognition proteins (PGRPs). We show that autolysins trim the outermost peptidoglycan fragments and that in their absence bacterial virulence is impaired, as PGRPs can directly recognize leftover peptidoglycan extending beyond the external layers of bacterial proteins and polysaccharides. The activity of autolysins is not restricted to the producer cells but can also alter the surface of neighboring bacteria, facilitating the survival of the entire population in the infected host. DOI: http://dx.doi.org/10.7554/eLife.02277.001.
authors.affiliation: Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal.|Genes and Development Laboratory, Department of Biochemistry, University of Oxford, Oxford, United Kingdom.
authors.forename: Magda Luciana
authors.initials: ML
authors.lastname: Atilano
authors.affiliation: Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal.
authors.forename: Pedro Matos
authors.initials: PM
authors.lastname: Pereira
authors.affiliation: Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal.
authors.forename: Filipa
authors.initials: F
authors.lastname: Vaz
authors.affiliation: Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Catalão
authors.affiliation: Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal.
authors.forename: Patricia
authors.initials: P
authors.lastname: Reed
authors.affiliation: Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal.
authors.forename: Inês Ramos
authors.initials: IR
authors.lastname: Grilo
authors.affiliation: Departamento de Ciências da Vida, Centro de Recursos Microbiologicos (CREM), Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.
authors.forename: Rita Gonçalves
authors.initials: RG
authors.lastname: Sobral
authors.affiliation: Genes and Development Laboratory, Department of Biochemistry, University of Oxford, Oxford, United Kingdom.
authors.forename: Petros
authors.initials: P
authors.lastname: Ligoxygakis
authors.affiliation: Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal.
authors.forename: Mariana Gomes
authors.initials: MG
authors.lastname: Pinho
authors.affiliation: Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal.
authors.forename: Sérgio Raposo
authors.initials: SR
authors.lastname: Filipe
mesh_terms: D000818:Animals; D004330:Drosophila / Q000276:immunology*; D006094:Gram-Positive Bacteria / Q000276:immunology* / Q000378:metabolism / Q000472:pathogenicity; D006868:Hydrolysis; D007113:Immunity, Innate; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000502:physiology*; D010457:Peptidoglycan / Q000378:metabolism*; D014774:Virulence
chemical_list: D010457:Peptidoglycan; D009238:N-Acetylmuramoyl-L-alanine Amidase
keywords: PGRP; Staphylococcus aureus; Streptococcus pneumoniae; bacterial infection; peptidoglycan; peptidoglycan hydrolases