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Håkansson, Sebastian
Publications (2 of 2) Show all publications
Holmström, A., Petterson, J., Rosqvist, R., Håkansson, S., Tafazoli, F., Fällman, M., . . . Forsberg, Å. (1997). YopK of Yersinia pseudotuberculosis controls translocation of Yop effectors across the eukaryotic cell membrane.. Molecular Microbiology, 24(1), 73-91
Open this publication in new window or tab >>YopK of Yersinia pseudotuberculosis controls translocation of Yop effectors across the eukaryotic cell membrane.
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1997 (English)In: Molecular Microbiology, ISSN 0950-382X, E-ISSN 1365-2958, Vol. 24, no 1, p. 73-91Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
John Wiley & Sons, 1997
National Category
Biological Sciences
Identifiers
urn:nbn:se:umu:diva-53002 (URN)10.1046/j.1365-2958.1997.3211681.x (DOI)9140967 (PubMedID)
Available from: 2012-03-09 Created: 2012-03-09 Last updated: 2018-06-08Bibliographically approved
Persson, C., Nordfelth, R., Holmström, A., Håkansson, S., Rosqvist, R. & Wolf-Watz, H. (1995). Cell-surface-bound Yersinia translocate the protein tyrosine phosphatase YopH by a polarized mechanism into the target cell. Molecular Microbiology, 18(1), 135-150
Open this publication in new window or tab >>Cell-surface-bound Yersinia translocate the protein tyrosine phosphatase YopH by a polarized mechanism into the target cell
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1995 (English)In: Molecular Microbiology, ISSN 0950-382X, E-ISSN 1365-2958, Vol. 18, no 1, p. 135-150Article in journal (Refereed) Published
Abstract [en]

YopH is translocated by cell-surface-bound bacteria through the plasma membrane to the cytosol of the HeLa cell. The transfer mechanism is contact dependent and polarizes the translocation to only occur at the contact zone between the bacterium and the target cell. More than 99% of the PTPase activity is associated with the HeLa cells. In contrast to the wild-type strain, the yopBD mutant cannot deliver YopH to the cytosol. Instead YopH is deposited in localized areas in the proximity of cell-associated bacteria. A yopN mutant secretes 40% of the total amount of YopH to the culture medium, suggesting a critical role of YopN in regulation of the polarized translocation. Evidence for a region in YopH important for its translocation through the plasma membrane of the target cell but not for secretion from the pathogen is provided.

Place, publisher, year, edition, pages
John Wiley & Sons, 1995
National Category
Biological Sciences
Identifiers
urn:nbn:se:umu:diva-53003 (URN)10.1111/j.1365-2958.1995.mmi_18010135.x (DOI)8596454 (PubMedID)
Available from: 2012-03-09 Created: 2012-03-09 Last updated: 2018-06-08Bibliographically approved
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