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- Holmström, Anna, et al.
(författare)
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LcrV is a channel size-determining component of the Yop effector translocon of Yersinia
- 2001
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Ingår i: Molecular Microbiology. - : Blackwell Publishing. - 0950-382X .- 1365-2958. ; 39:3, s. 620-632
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Tidskriftsartikel (refereegranskat)abstract
- Delivery of Yop effector proteins by pathogenic Yersinia across the eukaryotic cell membrane requires LcrV, YopB and YopD. These proteins were also required for channel formation in infected erythrocytes and, using different osmolytes, the contact‐dependent haemolysis assay was used to study channel size. Channels associated with LcrV were around 3 nm, whereas the homologous PcrV protein of Pseudomonas aeruginosa induced channels of around 2 nm in diameter. In lipid bilayer membranes, purified LcrV and PcrV induced a stepwise conductance increase of 3 nS and 1 nS, respectively, in 1 M KCl. The regions important for channel size were localized to amino acids 127–195 of LcrV and to amino acids 106–173 of PcrV. The size of the channel correlated with the ability to translocate Yop effectors into host cells. We suggest that LcrV is a size‐determining structural component of the Yop translocon.
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- Holmström, Anna, et al.
(författare)
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YopK of Yersinia pseudotuberculosis controls translocation of Yop effectors across the eukaryotic cell membrane
- 1997
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Ingår i: Molecular Microbiology. - : Wiley. - 0950-382X .- 1365-2958. ; 24:1, s. 73-91
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Tidskriftsartikel (refereegranskat)abstract
- Introduction of anti-host factors into eukaryotic cells by extracellular bacteria is a strategy evolved by several Gram-negative pathogens. In these pathogens, the transport of virulence proteins across the bacterial membranes is governed by closely related type III secretion systems. For pathogenic Yersinia, the protein transport across the eukaryotic cell membrane occurs by a polarized mechanism requiring two secreted proteins, YopB and YopD. YopB was recently shown to induce the formation of a pore in the eukaryotic cell membrane, and through this pore, translocation of Yop effectors is believed to occur (Håkansson et al., 1996b). We have previously shown that YopK of Yersinia pseudotuberculosis is required for the development of a systemic infection in mice. Here, we have analysed the role of YopK in the virulence process in more detail. A yopK-mutant strain was found to induce a more rapid YopE-mediated cytotoxic response in HeLa cells as well as in MDCK-1 cells compared to the wild-type strain. We found that this was the result of a cell-contact-dependent increase in translocation of YopE into HeLa cells. In contrast, overexpression of YopK resulted in impaired translocation. In addition, we found that YopK also influenced the YopB-dependent lytic effect on sheep erythrocytes as well as on HeLa cells. A yopK-mutant strain showed a higher lytic activity and the induced pore was larger compared to the corresponding wild-type strain, whereas a strain overexpressing YopK reduced the lytic activity and the apparent pore size was smaller. The secreted YopK protein was found not to be translocated but, similar to YopB, localized to cell-associated bacteria during infection of HeLa cells. Based on these results, we propose a model where YopK controls the translocation of Yop effectors into eukaryotic cells.
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- Lövgren, Janita, et al.
(författare)
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Production of recombinant PSA and HK2 and analysis of their immunologic cross-reactivity
- 1995
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Ingår i: Biochem Biophys Res Commun. - : Elsevier BV. ; 213:3, s. 888-895
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of prostate-specific antigen (PSA) in serum are widely used to monitor patients with prostate cancer, but the attenuation of the assay response by PSA complexed to protease inhibitors has been shown to affect the results in certain assay designs. Moreover, the human glandular kallikrein-2 (hK2), a kallikrein-like serine protease that is 80% similar to PSA, might interfere with the specific detection of PSA by immunological cross-reactivity. We have expressed hK2 and PSA in eucaryotic cells using the Semliki Forest Virus expression system and studied the reactivity of 18 monoclonal anti-PSA IgGs. Five of them cross-reacted with identical affinities to recombinant hK2 whereas 13 recognized PSA alone. The antibodies that recognized both PSA and hK2 bind to a region of the protein that is exposed when PSA is complexed to alpha-1-antichymotrypsin.
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- Pettersson, Hans-Åke, et al.
(författare)
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Blomatic. Ett alternativ
- 1978
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Consumer report ("avnämarrapport" in Swedish) for the company who financed this evaluation report.
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- Pettersson, Jonas, et al.
(författare)
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The V-antigen of Yersinia is surface exposed before target cell contact and involved in virulence protein translocation :
- 1999
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Ingår i: Molecular Microbiology. - : John Wiley & Sons. - 0950-382X .- 1365-2958. ; 32:5, s. 961-976
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Tidskriftsartikel (refereegranskat)abstract
- Type III-mediated translocation of Yop effectors is an essential virulence mechanism of pathogenic Yersinia. LcrV is the only protein secreted by the type III secretion system that induces protective immunity. LcrV also plays a significant role in the regulation of Yop expression and secretion. The role of LcrV in the virulence process has, however, remained elusive on account of its pleiotropic effects. Here, we show that anti-LcrV antibodies can block the delivery of Yop effectors into the target cell cytosol. This argues strongly for a critical role of LcrV in the Yop translocation process. Additional evidence supporting this role was obtained by genetic analysis. LcrV was found to be present on the bacterial surface before the establishment of bacteria target cell contact. These findings suggest that LcrV serves an important role in the initiation of the translocation process and provides one possible explanation for the mechanism of LcrV-induced protective immunity.
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