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A novel sheathed surface organelle of the Helicobacter pylori cag type IV secretion system
Author(s) -
Rohde Manfred,
Püls Jürgen,
Buhrdorf Renate,
Fischer Wolfgang,
Haas Rainer
Publication year - 2003
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2003.03549.x
Subject(s) - secretion , organelle , biology , caga , microbiology and biotechnology , bacterial outer membrane , pathogenicity island , type three secretion system , biochemistry , virulence , gene , escherichia coli
Summary Type I strains of Helicobacter pylori ( Hp ) use a type IV secretion system (T4SS), encoded by the cag pathogenicity island ( cag ‐PAI), to deliver the bacterial protein CagA into eukaryotic cells and to induce interleukin‐8 secretion. Translocated CagA is activated by tyrosine phosphorylation involving Src‐family kinases. The mechanism and structural basis for type IV protein secretion is not well understood. We describe here, by confocal laser scanning microscopy and field emission scanning electron microscopy, a novel filamentous surface organelle which is part of the Hp T4SS. The organelle is often located at one bacterial pole but can be induced by cell contact also along the lateral side of the bacteria. It consists of a rigid needle, covered focally or completely by HP0527 (Cag7 or CagY), a VirB10‐homologous protein. HP0527 is also clustered in the outer membrane. The VirB7‐homologous protein HP0532 is found at the base of this organelle. These observations demonstrate for the first time by microscopic techniques a complex T4SS‐associated, sheathed surface organelle reminiscent to the needle structures of bacterial type III secretion systems.