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Yasmin, Lubna
Publications (3 of 3) Show all publications
Yasmin, L., Veesenmeyer, J. L., Diaz, M. H., Francis, M. S., Ottmann, C., Palmer, R. H., . . . Hallberg, B. (2010). Electrostatic interactions play a minor role in the binding of ExoS to 14-3-3 proteins. Biochemical Journal, 427(2), 217-224
Open this publication in new window or tab >>Electrostatic interactions play a minor role in the binding of ExoS to 14-3-3 proteins
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2010 (English)In: Biochemical Journal, ISSN 0264-6021, E-ISSN 1470-8728, Vol. 427, no 2, p. 217-224Article in journal (Refereed) Published
Abstract [en]

14-3-3 proteins belong to a family of conserved molecules expressed in all eukaryotic cells that play an important role in a multitude of signalling pathways. 14-3-3 proteins bind either to phosphoserine/phosphothreonine residues or to sequence-specific non-phosphorylated motifs in more than 200 interaction partners [Pozuelo Rubio, Geraghty, Wong, Wood, Campbell, Morrice and Mackintosh (2004) Biochem. J. 379, 395-408]. These interactions result in cell-cycle regulation, apoptosis, stress responses, cell metabolism and malignant transformation. One example of a phosphorylation-independent interaction is the binding of 14-3-3 to ExoS (exoenzyme S), a bacterial ADP-ribosyltransferase toxin of Pseudomonas aeruginosa. In the present study, we have utilized additional biochemical and infection analyses to define further the structural basis of the interaction between ExoS and 14-3-3. An ExoS leucine-substitution mutant dramatically reduced the interaction potential with 14-3-3 suggesting that Leu422, Leu423, Leu426 and Leu428 of ExoS are important for its interaction with 14-3-3, its enzymatic activity and cytotoxicity. However, ExoS substitution mutants of residues that interact with 14-3-3 through an electrostatic interaction, such as Ser416, His418, Asp424 and Asp427, showed no reduction in their interaction potential with 14-3-3. These ExoS substitution mutants were also as aggressive as wild-type ExoS at inducing cell death and to modify endogenous ExoS target within the cell. In conclusion, electrostatic interaction between ExoS and 14-3-3 via polar residues (Ser416, His418, Asp424 and Asp427) appears to be of secondary importance. Thus the interaction between the 'roof' of the groove of 14-3-3 and ExoS relies more on hydrophobic interaction forces, which probably contributes to induce cell death after ExoS infection and activation.

Place, publisher, year, edition, pages
Portland Press, 2010
ADP-ribosyltransferase, Akt/protein kinase B (PKB), exoenzyme S (ExoS), 14-3-3 protein, Pseudomonas aeruginosa, Ras
National Category
Biochemistry and Molecular Biology
urn:nbn:se:umu:diva-33086 (URN)10.1042/BJ20100043 (DOI)000276867100004 ()20144150 (PubMedID)
Available from: 2010-04-12 Created: 2010-04-12 Last updated: 2018-06-08Bibliographically approved
Ottmann, C., Yasmin, L., Weyand, M., Veesenmeyer, J. L., Diaz, M. H., Palmer, R. H., . . . Hallberg, B. (2007). Phosphorylation-independent interaction between 14-3-3 and exoenzyme S: from structure to pathogenesis.. EMBO Journal, 26(3), 902-913
Open this publication in new window or tab >>Phosphorylation-independent interaction between 14-3-3 and exoenzyme S: from structure to pathogenesis.
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2007 (English)In: EMBO Journal, ISSN 0261-4189, E-ISSN 1460-2075, Vol. 26, no 3, p. 902-913Article in journal (Refereed) Published
Abstract [en]

14-3-3 proteins are phosphoserine/phosphothreonine-recognizing adapter proteins that regulate the activity of a vast array of targets. There are also examples of 14-3-3 proteins binding their targets via unphosphorylated motifs. Here we present a structural and biological investigation of the phosphorylation-independent interaction between 14-3-3 and exoenzyme S (ExoS), an ADP-ribosyltransferase toxin of Pseudomonas aeruginosa. ExoS binds to 14-3-3 in a novel binding mode mostly relying on hydrophobic contacts. The 1.5 A crystal structure is supported by cytotoxicity analysis, which reveals that substitution of the corresponding hydrophobic residues significantly weakens the ability of ExoS to modify the endogenous targets RAS/RAP1 and to induce cell death. Furthermore, mutation of key residues within the ExoS binding site for 14-3-3 impairs virulence in a mouse pneumonia model. In conclusion, we show that ExoS binds 14-3-3 in a novel reversed orientation that is primarily dependent on hydrophobic residues. This interaction is phosphorylation independent and is required for the function of ExoS.

14-3-3 Proteins/*genetics/*metabolism, ADP Ribose Transferases/*metabolism, Animals, Bacterial Toxins/*metabolism, Blotting; Western, Crystallography, DNA Primers, Female, Hela Cells, Humans, Mice, Mice; Inbred BALB C, Models; Molecular, Molecular Conformation, Mutation/genetics, Pneumonia/*microbiology, Protein Binding, Pseudomonas aeruginosa/enzymology/*pathogenicity, rap1 GTP-Binding Proteins/metabolism
urn:nbn:se:umu:diva-18052 (URN)10.1038/sj.emboj.7601530 (DOI)17235285 (PubMedID)
Available from: 2008-01-10 Created: 2008-01-10 Last updated: 2018-06-09Bibliographically approved
Yasmin, L., Jansson, A. L., Panahandeh, T., Palmer, R. H., Francis, M. S. & Hallberg, B. (2006). Delineation of exoenzyme S residues that mediate the interaction with 14-3-3 and its biological activity.. The FEBS Journal, 273(3), 638-646
Open this publication in new window or tab >>Delineation of exoenzyme S residues that mediate the interaction with 14-3-3 and its biological activity.
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2006 (English)In: The FEBS Journal, ISSN 1742-464X, E-ISSN 1742-4658, Vol. 273, no 3, p. 638-646Article in journal (Refereed) Published
14-3-3 Proteins/*physiology, ADP Ribose Transferases/metabolism/pharmacology/*physiology, Amino Acid Motifs, Bacterial Toxins/metabolism/pharmacology, Cell Death/drug effects, Cells; Cultured, Enzyme Activation, Hela Cells, Humans, Leucine/chemistry/metabolism, Phosphorylation, Protein Binding, Pseudomonas aeruginosa/enzymology, Signal Transduction/physiology
urn:nbn:se:umu:diva-15367 (URN)10.1111/j.1742-4658.2005.05100.x (DOI)16420486 (PubMedID)
Available from: 2008-01-11 Created: 2008-01-11 Last updated: 2018-06-09Bibliographically approved

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