Medical College of Wisconsin
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Intracellular localization modulates targeting of ExoS, a type III cytotoxin, to eukaryotic signalling proteins. Mol Microbiol 2002 Dec;46(5):1381-90

Date

11/28/2002

Pubmed ID

12453223

DOI

10.1046/j.1365-2958.2002.03256.x

Scopus ID

2-s2.0-0036887054 (requires institutional sign-in at Scopus site)   42 Citations

Abstract

ExoS is a bifunctional type III cytotoxin produced by Pseudomonas aeruginosa. Residues 96-232 comprise the Rho GTPase activating protein (Rho GAP) domain, whereas residues 233-453 comprise the 14-3-3-dependent ADP-ribosyltransferase domain. Earlier studies showed that the N-terminus targeted ExoS to intracellular membranes within eukaryotic cells. This N-terminal targeting region is now characterized for cellular and biological contributions to intoxications by ExoS. An ExoS(1-107)-green fluorescent protein (GFP) fusion protein co-localized with alpha-mannosidase, which indicated that the fusion protein localized near the Golgi. Residues 51-72 of ExoS (termed the membrane localization domain, MLD) were necessary and sufficient for membrane localization within eukaryotic cells. Deletion of the MLD did not inhibit type III secretion of ExoS from P. aeruginosa or type III delivery of ExoS into eukaryotic cells. Type III-delivered ExoS(DeltaMLD) localized within the cytosol of eukaryotic cells, whereas type III-delivered ExoS was membrane associated. Although type III-delivered ExoS(DeltaMLD) stimulated the reorganization of the actin cytoskeleton (a Rho GAP activity), it did not ADP-ribosylate Ras. Type III-delivered ExoS(DeltaMLD) and ExoS showed similar capacities for eliciting a cytotoxic response in CHO cells, which uncoupled the ADP-ribosylation of Ras from the cytotoxicity elicited by ExoS.

Author List

Pederson KJ, Krall R, Riese MJ, Barbieri JT

Author

Joseph T. Barbieri PhD Professor in the Microbiology and Immunology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

ADP Ribose Transferases
Actins
Animals
CHO Cells
Cell Membrane
Cricetinae
Cytoskeleton
Cytotoxins
Green Fluorescent Proteins
Histidine Kinase
Luminescent Proteins
Protein Kinases
Pseudomonas aeruginosa
Recombinant Fusion Proteins
ras Proteins