TY - JOUR
T1 - Expression and cytoprotective activity of the small GTPase RhoB induced by the Escherichia coli cytotoxic necrotizing factor 1
AU - Huelsenbeck, Stefanie C
AU - Roggenkamp, Dennis
AU - May, Martin
AU - Huelsenbeck, Johannes
AU - Brakebusch, Cord Herbert
AU - Rottner, Klemens
AU - Ladwein, Markus
AU - Just, Ingo
AU - Fritz, Gerhard
AU - Schmidt, Gudula
AU - Genth, Harald
N1 - Copyright © 2013 Elsevier Ltd. All rights reserved.
PY - 2013/8
Y1 - 2013/8
N2 - RhoB is the only member of the Rho subfamily of small GTPases, which is classified as an immediate early gene product. RhoB is up-regulated in response to growth factors as well as cytotoxic and genotoxic agents. Clostridial glucosylating toxins have been reported to evoke pronounced RhoB expression, based on the inactivation of Rho/Ras proteins. In this study, we report on a long lasting expression of RhoB in cultured cells upon activation of Rho proteins by the cytotoxic necrotizing factor 1 (CNF1) from Escherichia coli. The observations of this study highlight a new pathway involving Rac1, which positively regulates the activity of the rhoB promoter and RhoB expression. Conversely, the isomeric cytotoxic necrotizing factor from Yersinia pseudotuberculosis (CNFy) drives GTP-loading of basal RhoB but fails to cause activation of the rhoB promoter and thus its expression. CNF1 inhibits cytokinesis and induces the formation of bi-nucleated (tetraploid) cells. Upon long term treatment with CNF1, RhoB(-/-) mouse embryonic fibroblasts (MEFs) exhibit DNA fragmentation, phosphatidylserine exposure, and loss of membrane integrity, while RhoB(+/-) MEFs persist as bi-nucleated (tetraploid) cells without any signs of cell death. In conclusion, the cytoprotective RhoB response is not only evoked by bacterial protein toxins inactivating Rho/Ras proteins but also by the Rac1-activating toxin CNF1.
AB - RhoB is the only member of the Rho subfamily of small GTPases, which is classified as an immediate early gene product. RhoB is up-regulated in response to growth factors as well as cytotoxic and genotoxic agents. Clostridial glucosylating toxins have been reported to evoke pronounced RhoB expression, based on the inactivation of Rho/Ras proteins. In this study, we report on a long lasting expression of RhoB in cultured cells upon activation of Rho proteins by the cytotoxic necrotizing factor 1 (CNF1) from Escherichia coli. The observations of this study highlight a new pathway involving Rac1, which positively regulates the activity of the rhoB promoter and RhoB expression. Conversely, the isomeric cytotoxic necrotizing factor from Yersinia pseudotuberculosis (CNFy) drives GTP-loading of basal RhoB but fails to cause activation of the rhoB promoter and thus its expression. CNF1 inhibits cytokinesis and induces the formation of bi-nucleated (tetraploid) cells. Upon long term treatment with CNF1, RhoB(-/-) mouse embryonic fibroblasts (MEFs) exhibit DNA fragmentation, phosphatidylserine exposure, and loss of membrane integrity, while RhoB(+/-) MEFs persist as bi-nucleated (tetraploid) cells without any signs of cell death. In conclusion, the cytoprotective RhoB response is not only evoked by bacterial protein toxins inactivating Rho/Ras proteins but also by the Rac1-activating toxin CNF1.
KW - Animals
KW - Bacterial Toxins
KW - Cell Death
KW - Cell Shape
KW - Cytoprotection
KW - Enzyme Activation
KW - Escherichia coli
KW - Escherichia coli Proteins
KW - Gene Expression Regulation
KW - HT29 Cells
KW - HeLa Cells
KW - Humans
KW - Mice
KW - NIH 3T3 Cells
KW - Polyploidy
KW - Promoter Regions, Genetic
KW - RNA, Messenger
KW - Transcriptional Activation
KW - Yersinia pseudotuberculosis
KW - rac1 GTP-Binding Protein
KW - rhoB GTP-Binding Protein
U2 - 10.1016/j.biocel.2013.05.020
DO - 10.1016/j.biocel.2013.05.020
M3 - Journal article
C2 - 23732113
SN - 1357-2725
VL - 45
SP - 1767
EP - 1775
JO - International Journal of Biochemistry & Cell Biology
JF - International Journal of Biochemistry & Cell Biology
IS - 8
ER -