title: Lipid raft microdomains mediate class A scavenger receptor-dependent infection of Brucella abortus.
abstract: Brucella abortus is a facultative intracellular bacterium that can survive inside macrophages. Intracellular replication of B. abortus requires the VirB complex, which is highly similar to the conjugative DNA transfer system. In this study, we showed that a class A scavenger receptor (SR-A) of macrophages is required to internalize B. abortus and contributes to the establishment of bacterial infection in mice. Macrophages from SR-A-deficient mice inhibited internalization and intracellular replication of both wild type strain and the virB4 mutant, and that bacterial proliferation was inhibited in SR-A-deficient mice. Adding lipopolysaccharide from B. abortus and Salmonella enterica serovar Typhimurium, but not from Escherichia coli, to macrophages inhibited bacterial internalization. VirB-dependent bacterial internalization induced localization of SR-A into detergent-resistant membrane lipid rafts. These results indicate that B. abortus internalizes into macrophages by using SR-A as a receptor and that the VirB type IV secretion system of B. abortus regulates signal transduction dependent on SR-A to form replicative phagosomes, and which is mediated by lipid rafts.
authors.affiliation: Department of Applied Veterinary Science, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro-shi, Hokkaido 080-8555, Japan.
authors.forename: Suk
authors.initials: S
authors.lastname: Kim
authors.forename: Masahisa
authors.initials: M
authors.lastname: Watarai
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Suzuki
authors.forename: Sou-ichi
authors.initials: S
authors.lastname: Makino
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Kodama
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Shirahata
mesh_terms: D000818:Animals; D002003:Brucella abortus / Q000254:growth & development / Q000472:pathogenicity*; D002006:Brucellosis / Q000382:microbiology* / Q000473:pathology; D002462:Cell Membrane / Q000382:microbiology; D002478:Cells, Cultured; D015169:Colony Count, Microbial; D003593:Cytoplasm / Q000382:microbiology; D004926:Escherichia coli; D008264:Macrophages / Q000276:immunology / Q000382:microbiology*; D021962:Membrane Microdomains / Q000378:metabolism* / Q000382:microbiology; D051379:Mice; D010587:Phagocytosis; D010588:Phagosomes / Q000382:microbiology; D011971:Receptors, Immunologic / Q000378:metabolism*; D051116:Receptors, Scavenger; D019779:Salmonella enterica; D051117:Scavenger Receptors, Class A; D015398:Signal Transduction; D013154:Spleen / Q000382:microbiology; D014774:Virulence
chemical_list: D011971:Receptors, Immunologic; D051116:Receptors, Scavenger; D051117:Scavenger Receptors, Class A