title: Type III secretion translocon assemblies that attenuate Yersinia virulence.
abstract: Type III secretion enables bacteria to intoxicate eukaryotic cells with anti-host effectors. A class of secreted cargo are the two hydrophobic translocators that form a translocon pore in the host cell plasma membrane through which the translocated effectors may gain cellular entry. In pathogenic Yersinia, YopB and YopD shape this translocon pore. Here, four in cis yopD mutations were constructed to disrupt a predicted α-helix motif at the C-terminus. Mutants YopD(I262P) and YopD(K267P) poorly localized Yop effectors into target eukaryotic cells and failed to resist uptake and killing by immune cells. These defects were due to deficiencies in host-membrane insertion of the YopD-YopB translocon. Mutants YopDA(263P) and YopD(A270P) had no measurable in vitro translocation defect, even though they formed smaller translocon pores in erythrocyte membranes. Despite this, all four mutants were attenuated in a mouse infection model. Hence, YopD variants have been generated that can spawn translocons capable of targeting effectors in vitro, yet were bereft of any lethal effect in vivo. Therefore, Yop translocators may possess other in vivo functions that extend beyond being a portal for effector delivery into host cells.
authors.affiliation: Department of Molecular Biology, Umeå University, SE-901 87, Umeå, Sweden.
authors.forename: Tiago R D
authors.initials: TR
authors.lastname: Costa
authors.forename: Ayad A A
authors.initials: AA
authors.lastname: Amer
authors.forename: Salah I
authors.initials: SI
authors.lastname: Farag
authors.forename: Hans
authors.initials: H
authors.lastname: Wolf-Watz
authors.forename: Maria
authors.initials: M
authors.lastname: Fällman
authors.forename: Anna
authors.initials: A
authors.lastname: Fahlgren
authors.forename: Tomas
authors.initials: T
authors.lastname: Edgren
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Francis
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D058947:Bacterial Secretion Systems; D002460:Cell Line; D004252:DNA Mutational Analysis; D004195:Disease Models, Animal; D008264:Macrophages / Q000276:immunology / Q000382:microbiology; D051379:Mice; D014774:Virulence; D015009:Yersinia Infections / Q000382:microbiology / Q000473:pathology; D015011:Yersinia pseudotuberculosis / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D058947:Bacterial Secretion Systems; C078910:YopD protein, Yersinia