title: The Amino-Terminal Part of the Needle-Tip Translocator LcrV ofYersinia pseudotuberculosisIs Required for Early Targeting of YopH andIn vivoVirulence.
abstract: Type III secretion systems (T3SS) are dedicated to targeting anti-host effector proteins into the cytosol of the host cell to promote bacterial infection. Delivery of the effectors requires three specific translocator proteins, of which the hydrophilic translocator, LcrV, is located at the tip of the T3SS needle and is believed to facilitate insertion of the two hydrophobic translocators into the host cell membrane. Here we usedYersiniaas a model to study the role of LcrV in T3SS mediated intracellular effector targeting. Intriguingly, we identified N-terminallcrVmutants that, similar to the wild-type protein, efficiently promoted expression, secretion and intracellular levels of Yop effectors, yet they were impaired in their ability to inhibit phagocytosis by J774 cells. In line with this, the YopH mediated dephosphorylation of Focal Adhesion Kinase early after infection was compromised when compared to the wild type strain. This suggests that the mutants are unable to promote efficient delivery of effectors to their molecular targets inside the host cell upon host cell contact. The significance of this was borne out by the fact that the mutants were highly attenuated for virulence in the systemic mouse infection model. Our study provides both novel and significant findings that establish a role for LcrV in early targeting of effectors in the host cell.
authors.affiliation: Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå UniversityUmeå, Sweden; Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå UniversityUmeå, Sweden.
authors.forename: Sofie
authors.initials: S
authors.lastname: Ekestubbe
authors.affiliation: Department of Clinical Microbiology, Umeå University Umeå, Sweden.
authors.forename: Jeanette E
authors.initials: JE
authors.lastname: Bröms
authors.affiliation: Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University Umeå, Sweden.
authors.forename: Tomas
authors.initials: T
authors.lastname: Edgren
authors.affiliation: Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå UniversityUmeå, Sweden; Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå UniversityUmeå, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Fällman
authors.affiliation: Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University Umeå, Sweden.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Francis
authors.affiliation: Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå UniversityUmeå, Sweden; Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå UniversityUmeå, Sweden.
authors.forename: Åke
authors.initials: Å
authors.lastname: Forsberg
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000378:metabolism*; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D008264:Macrophages; D051379:Mice; D010587:Phagocytosis; D052899:Pore Forming Cytotoxic Proteins / Q000378:metabolism*; D021381:Protein Transport; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D014774:Virulence; D037521:Virulence Factors / Q000378:metabolism*; D015011:Yersinia pseudotuberculosis / Q000472:pathogenicity*
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; C043908:LcrV protein, Yersinia; D052899:Pore Forming Cytotoxic Proteins; D037521:Virulence Factors; D017027:Protein Tyrosine Phosphatases; C067571:yopH protein, Yersinia
keywords: LcrV; Yersinia pseudotuberculosis; YopH; pore formation; translocation; type III secretion system; virulence