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14-3-3 proteins activate Pseudomonas exotoxins-S and -T by chaperoning a hydrophobic surface

Karlberg, Tobias LU ; Hornyak, Peter ; Pinto, Ana Filipa ; Milanova, Stefina ; Ebrahimi, Mahsa ; Lindberg, Mikael ; Püllen, Nikolai ; Nordström, Axel ; Löverli, Elinor and Caraballo, Rémi , et al. (2018) In Nature Communications 9(1).
Abstract

Pseudomonas are a common cause of hospital-acquired infections that may be lethal. ADP-ribosyltransferase activities of Pseudomonas exotoxin-S and -T depend on 14-3-3 proteins inside the host cell. By binding in the 14-3-3 phosphopeptide binding groove, an amphipathic C-terminal helix of ExoS and ExoT has been thought to be crucial for their activation. However, crystal structures of the 14-3-3β:ExoS and -ExoT complexes presented here reveal an extensive hydrophobic interface that is sufficient for complex formation and toxin activation. We show that C-terminally truncated ExoS ADP-ribosyltransferase domain lacking the amphipathic binding motif is active when co-expressed with 14-3-3. Moreover, swapping the amphipathic C-terminus with a... (More)

Pseudomonas are a common cause of hospital-acquired infections that may be lethal. ADP-ribosyltransferase activities of Pseudomonas exotoxin-S and -T depend on 14-3-3 proteins inside the host cell. By binding in the 14-3-3 phosphopeptide binding groove, an amphipathic C-terminal helix of ExoS and ExoT has been thought to be crucial for their activation. However, crystal structures of the 14-3-3β:ExoS and -ExoT complexes presented here reveal an extensive hydrophobic interface that is sufficient for complex formation and toxin activation. We show that C-terminally truncated ExoS ADP-ribosyltransferase domain lacking the amphipathic binding motif is active when co-expressed with 14-3-3. Moreover, swapping the amphipathic C-terminus with a fragment from Vibrio Vis toxin creates a 14-3-3 independent toxin that ADP-ribosylates known ExoS targets. Finally, we show that 14-3-3 stabilizes ExoS against thermal aggregation. Together, this indicates that 14-3-3 proteins activate exotoxin ADP-ribosyltransferase domains by chaperoning their hydrophobic surfaces independently of the amphipathic C-terminal segment.

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publishing date
type
Contribution to journal
publication status
published
keywords
14-3-3 Proteins/chemistry, ADP Ribose Transferases/chemistry, Bacterial Toxins/chemistry, Binding Sites, Crystallography, X-Ray, Escherichia coli/genetics, GTPase-Activating Proteins/chemistry, Host-Pathogen Interactions, Hydrophobic and Hydrophilic Interactions, Models, Molecular, Molecular Chaperones/chemistry, Protein Conformation, Protein Domains, Pseudomonas aeruginosa/pathogenicity, Saccharomyces cerevisiae/genetics
in
Nature Communications
volume
9
issue
1
article number
3785
publisher
Nature Publishing Group
external identifiers
  • pmid:30224724
  • scopus:85053414923
ISSN
2041-1723
DOI
10.1038/s41467-018-06194-1
language
English
LU publication?
no
id
58b70b3f-20f2-4d27-b514-db4246f5e31e
date added to LUP
2024-11-21 17:48:41
date last changed
2025-06-06 20:27:49
@article{58b70b3f-20f2-4d27-b514-db4246f5e31e,
  abstract     = {{<p>Pseudomonas are a common cause of hospital-acquired infections that may be lethal. ADP-ribosyltransferase activities of Pseudomonas exotoxin-S and -T depend on 14-3-3 proteins inside the host cell. By binding in the 14-3-3 phosphopeptide binding groove, an amphipathic C-terminal helix of ExoS and ExoT has been thought to be crucial for their activation. However, crystal structures of the 14-3-3β:ExoS and -ExoT complexes presented here reveal an extensive hydrophobic interface that is sufficient for complex formation and toxin activation. We show that C-terminally truncated ExoS ADP-ribosyltransferase domain lacking the amphipathic binding motif is active when co-expressed with 14-3-3. Moreover, swapping the amphipathic C-terminus with a fragment from Vibrio Vis toxin creates a 14-3-3 independent toxin that ADP-ribosylates known ExoS targets. Finally, we show that 14-3-3 stabilizes ExoS against thermal aggregation. Together, this indicates that 14-3-3 proteins activate exotoxin ADP-ribosyltransferase domains by chaperoning their hydrophobic surfaces independently of the amphipathic C-terminal segment.</p>}},
  author       = {{Karlberg, Tobias and Hornyak, Peter and Pinto, Ana Filipa and Milanova, Stefina and Ebrahimi, Mahsa and Lindberg, Mikael and Püllen, Nikolai and Nordström, Axel and Löverli, Elinor and Caraballo, Rémi and Wong, Emily V and Näreoja, Katja and Thorsell, Ann-Gerd and Elofsson, Mikael and De La Cruz, Enrique M and Björkegren, Camilla and Schüler, Herwig}},
  issn         = {{2041-1723}},
  keywords     = {{14-3-3 Proteins/chemistry; ADP Ribose Transferases/chemistry; Bacterial Toxins/chemistry; Binding Sites; Crystallography, X-Ray; Escherichia coli/genetics; GTPase-Activating Proteins/chemistry; Host-Pathogen Interactions; Hydrophobic and Hydrophilic Interactions; Models, Molecular; Molecular Chaperones/chemistry; Protein Conformation; Protein Domains; Pseudomonas aeruginosa/pathogenicity; Saccharomyces cerevisiae/genetics}},
  language     = {{eng}},
  month        = {{09}},
  number       = {{1}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Nature Communications}},
  title        = {{14-3-3 proteins activate <i>Pseudomonas</i> exotoxins-S and -T by chaperoning a hydrophobic surface}},
  url          = {{http://dx.doi.org/10.1038/s41467-018-06194-1}},
  doi          = {{10.1038/s41467-018-06194-1}},
  volume       = {{9}},
  year         = {{2018}},
}