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Sundberg, Lena
Publications (3 of 3) Show all publications
Lavander, M., Sundberg, L., Edqvist, P. J., Lloyd, S. A., Wolf-Watz, H. & Forsberg, A. (2003). Characterisation of the type III secretion protein YscU in Yersinia pseudotuberculosis: YscU cleavage--dispensable for TTSS but essential for survival. Advances in Experimental Medicine and Biology, 529, 109-112
Open this publication in new window or tab >>Characterisation of the type III secretion protein YscU in Yersinia pseudotuberculosis: YscU cleavage--dispensable for TTSS but essential for survival
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2003 (English)In: Advances in Experimental Medicine and Biology, ISSN 0065-2598, E-ISSN 2214-8019, Vol. 529, p. 109-112Article in journal (Other academic) Published
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:umu:diva-33328 (URN)10.1007/0-306-48416-1_20 (DOI)12756738 (PubMedID)
Available from: 2010-04-21 Created: 2010-04-21 Last updated: 2019-01-21Bibliographically approved
Edqvist, P., Olsson, J., Lavander, M., Sundberg, L., Forsberg, Å., Wolf-Watz, H. & Lloyd, S. (2003). YscP and YscU Regulate Substrate Specificity of the Yersinia Type III Secretion System. Journal of Bacteriology, 185(7), 2259-2266
Open this publication in new window or tab >>YscP and YscU Regulate Substrate Specificity of the Yersinia Type III Secretion System
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2003 (English)In: Journal of Bacteriology, ISSN 0021-9193, E-ISSN 1098-5530, Vol. 185, no 7, p. 2259-2266Article in journal (Refereed) Published
Abstract [en]

Pathogenic Yersinia species use a type III secretion system to inhibit phagocytosis by eukaryotic cells. At 37 degrees C, the secretion system is assembled, forming a needle-like structure on the bacterial cell surface. Upon eukaryotic cell contact, six effector proteins, called Yops, are translocated into the eukaryotic cell cytosol. Here, we show that a yscP mutant exports an increased amount of the needle component YscF to the bacterial cell surface but is unable to efficiently secrete effector Yops. Mutations in the cytoplasmic domain of the inner membrane protein YscU suppress the yscP phenotype by reducing the level of YscF secretion and increasing the level of Yop secretion. These results suggest that YscP and YscU coordinately regulate the substrate specificity of the Yersinia type III secretion system. Furthermore, we show that YscP and YscU act upstream of the cell contact sensor YopN as well as the inner gatekeeper LcrG in the pathway of substrate export regulation. These results further strengthen the strong evolutionary link between flagellar biosynthesis and type III synthesis.

Place, publisher, year, edition, pages
American Society for Microbiology, 2003
National Category
Biochemistry and Molecular Biology Microbiology in the medical area
Identifiers
urn:nbn:se:umu:diva-4776 (URN)10.1128/JB.185.7.2259-2266.2003 (DOI)000181703700023 ()12644497 (PubMedID)
Available from: 2005-10-27 Created: 2005-10-27 Last updated: 2019-01-24Bibliographically approved
Lavander, M., Sundberg, L., Edqvist, P., Lloyd, S., Wolf-Watz, H. & Forsberg, Å. (2002). Proteolytic Cleavage of the FlhB Homologue YscU of Yersinia pseudotuberculosis Is Essential for Bacterial Survival. Journal of Bacteriology, 184(16), 4500-4509
Open this publication in new window or tab >>Proteolytic Cleavage of the FlhB Homologue YscU of Yersinia pseudotuberculosis Is Essential for Bacterial Survival
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2002 (English)In: Journal of Bacteriology, ISSN 0021-9193, E-ISSN 1098-5530, Vol. 184, no 16, p. 4500-4509Article in journal (Refereed) Published
Abstract [en]

Pathogenic Yersinia species employ a type III secretion system (TTSS) to target antihost factors, Yop proteins, into eukaryotic cells. The secretion machinery is constituted of ca. 20 Ysc proteins, nine of which show significant homology to components of the flagellar TTSS. A key event in flagellar assembly is the switch from secreting-assembling hook substrates to filament substrates, a switch regulated by FlhB and FliK. The focus of this study is the FlhB homologue YscU, a bacterial inner membrane protein with a large cytoplasmic C-terminal domain. Our results demonstrate that low levels of YscU were required for functional Yop secretion, whereas higher levels of YscU lowered both Yop secretion and expression. Like FlhB, YscU was cleaved into a 30-kDa N-terminal and a 10-kDa C-terminal part. Expression of the latter in a wild-type strain resulted in elevated Yop secretion. The site of cleavage was at a proline residue, within the strictly conserved amino acid sequence NPTH. A YscU protein with an in-frame deletion of NPTH was cleaved at a different position and was nonfunctional with respect to Yop secretion. Variants of YscU with single substitutions in the conserved NPTH sequence--i.e., N263A, P264A, or T265A--were not cleaved but retained function in Yop secretion. Elevated expression of these YscU variants did, however, result in severe growth inhibition. From this we conclude that YscU cleavage is not a prerequisite for Yop secretion but is rather required to maintain a nontoxic fold.

Place, publisher, year, edition, pages
American Society for Microbiology, 2002
National Category
Microbiology in the medical area Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-4777 (URN)10.1128/JB.184.16.4500-4509.2002 (DOI)000177059500020 ()12142420 (PubMedID)
Available from: 2005-10-27 Created: 2005-10-27 Last updated: 2019-01-23Bibliographically approved
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