scholarly journals Cleavage of Escherichia coli Cytotoxic Necrotizing Factor 1 Is Required for Full Biologic Activity

2009 ◽  
Vol 77 (5) ◽  
pp. 1835-1841 ◽  
Author(s):  
Zeynep Knust ◽  
Britta Blumenthal ◽  
Klaus Aktories ◽  
Gudula Schmidt
Keyword(s):  
Escherichia Coli ◽  
Mammalian Cells ◽  
Catalytic Domain ◽  
Small Gtpases ◽  
Gtp Hydrolysis ◽  
Cytotoxic Necrotizing Factor ◽  
Endosomal Membrane ◽  
Protein Toxin ◽  
Late Endosomes ◽  
Cytotoxic Necrotizing Factor 1

ABSTRACT Cytotoxic necrotizing factor 1 (CNF1) is a protein toxin produced by pathogenic Escherichia coli strains. CNF1 constitutively activates small GTPases of the Rho family by deamidation of a glutamine, which is crucial for GTP hydrolysis. The toxin is taken up into mammalian cells by receptor-mediated endocytosis and is delivered from late endosomes into the cytosol. Here, we show that an approximately 55-kDa fragment of CNF1, which contains the catalytic domain and an additional part of the toxin, is present in the cytosol. The processing of this fragment requires an acidic pH and insertion of the toxin into the endosomal membrane. We define the cleavage site region as the region located between amino acids 532 and 544 of CNF1. The data provide insight into the complex mechanism of uptake of bacterial toxins into mammalian cells.

The Escherichia coli protein toxin cytotoxic necrotizing factor 1 induces epithelial mesenchymal transition

2019 ◽  
Vol 22 (2) ◽  
Author(s):  
Alessia Fabbri ◽  
Sara Travaglione ◽  
Francesca Rosadi ◽  
Giulia Ballan ◽  
Zaira Maroccia ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Epithelial Mesenchymal Transition ◽  
Mesenchymal Transition ◽  
Cytotoxic Necrotizing Factor ◽  
Protein Toxin ◽  
Cytotoxic Necrotizing Factor 1

scholarly journals Escherichia coli Cytotoxic Necrotizing Factor 1 Blocks Cell Cycle G2/M Transition in Uroepithelial Cells

2006 ◽  
Vol 74 (7) ◽  
pp. 3765-3772 ◽  
Author(s):  
Loredana Falzano ◽  
Perla Filippini ◽  
Sara Travaglione ◽  
Alessandro Giamboi Miraglia ◽  
Alessia Fabbri ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Cycle ◽  
Rho Gtpases ◽  
Cell Cycle Progression ◽  
Cyclin B1 ◽  
Eukaryotic Cell ◽  
Cytotoxic Necrotizing Factor ◽  
Cytoskeleton Organization ◽  
Protein Toxin ◽  
Cytotoxic Necrotizing Factor 1

ABSTRACT Evidence is accumulating that a growing number of bacterial toxins act by modulating the eukaryotic cell cycle machinery. In this context, we provide evidence that a protein toxin named cytotoxic necrotizing factor 1 (CNF1) from uropathogenic Escherichia coli is able to block cell cycle G2/M transition in the uroepithelial cell line T24. CNF1 permanently activates the small GTP-binding proteins of the Rho family that, beside controlling the actin cytoskeleton organization, also play a pivotal role in a large number of other cellular processes, including cell cycle regulation. The results reported here show that CNF1 is able to induce the accumulation of cells in the G2/M phase by sequestering cyclin B1 in the cytoplasm and down-regulating its expression. The possible role played by the Rho GTPases in the toxin-induced cell cycle deregulation has been investigated and discussed. The activity of CNF1 on cell cycle progression can offer a novel view of E. coli pathogenicity.

Rho-activating Escherichia coli cytotoxic necrotizing factor 1: macropinocytosis of apoptotic bodies in human epithelial cells

2001 ◽  
Vol 291 (6-7) ◽  
pp. 551-554 ◽  
Author(s):  
Alessia Fabbri ◽  
Loredana Falzano ◽  
Sara Travaglione ◽  
Annarita Stringaro ◽  
Walter Malorni ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Apoptotic Bodies ◽  
Cytotoxic Necrotizing Factor ◽  
Human Epithelial Cells ◽  
Cytotoxic Necrotizing Factor 1

scholarly journals High Affinity Binding of Escherichia coli Cytotoxic Necrotizing Factor 1 (CNF1) to Lu/BCAM Adhesion Glycoprotein

Toxins ◽  
2017 ◽  
Vol 10 (1) ◽  
pp. 3 ◽  
Author(s):  
Franziska Reppin ◽  
Sylvie Cochet ◽  
Wassim El Nemer ◽  
Günter Fritz ◽  
Gudula Schmidt
Keyword(s):  
Escherichia Coli ◽  
Affinity Binding ◽  
High Affinity Binding ◽  
Cytotoxic Necrotizing Factor ◽  
High Affinity ◽  
Cytotoxic Necrotizing Factor 1

scholarly journals Cytotoxic Necrotizing Factor Type 2 Produced by Pathogenic Escherichia coli Deamidates a Gln Residue in the Conserved G-3 Domain of the Rho Family and Preferentially Inhibits the GTPase Activity of RhoA and Rac1

1999 ◽  
Vol 67 (12) ◽  
pp. 6550-6557 ◽  
Author(s):  
Motoyuki Sugai ◽  
Kiyotaka Hatazaki ◽  
Akira Mogami ◽  
Hiroyuki Ohta ◽  
Sylvie Y. Pérès ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Cultured Cells ◽  
Peptide Mapping ◽  
Small Gtpases ◽  
Amino Acid Sequences ◽  
Gtpase Activity ◽  
Toxic Activity ◽  
Cytotoxic Necrotizing Factor ◽  
Rho Family

ABSTRACT Cytotoxic necrotizing factor types 1 and 2 (CNF1 and -2) produced by pathogenic Escherichia coli strains have 90% conserved residues over 1,014-amino-acid sequences. Both CNFs are able to provoke a remarkable increase in F-actin structures in cultured cells and covalently modify the RhoA small GTPases. In this study, we demonstrated that CNF2 reduced RhoA GTPase activity in the presence and absence of P122RhoGAP. Subsequently, peptide mapping and amino acid sequencing of CNF2-modified FLAG-RhoA produced in E. coli revealed that CNF2 deamidates Q63 of RhoA-like CNF1. In vitro incubation of the C-terminal domain of CNF2 with FLAG-RhoA resulted also in deamidation of the FLAG-RhoA, suggesting that this region contains the enzymatic domain of CNF2. An oligopeptide antibody (anti-E63) which specifically recognized the altered G-3 domain of the Rho family reacted with glutathione S-transferase (GST)-RhoA and GST-Rac1 but not with GST-Cdc42 when coexpressed with CNF2. In addition, CNF2 selectively induced accumulation of GTP form of FLAG-RhoA and FLAG-Rac1 but not of FLAG-Cdc42 in Cos-7 cells. Taken together, these results indicate that CNF2 preferentially deamidates RhoA Q63 and Rac1 Q61 and constitutively activates these small GTPases in cultured cells. In contrast, anti-E63 reacted with GST-RhoA and GST-Cdc42 but not with GST-Rac1 when coexpressed with CNF1. These results indicate that CNF2 and CNF1 share the same catalytic activity but have distinct substrate specificities, which may reflect their differences in toxic activity in vivo.

scholarly journals Effect of Escherichia coli Cytotoxic Necrotizing Factor 1 on Repair of Human Bladder Cell Monolayers In Vitro

1999 ◽  
Vol 67 (7) ◽  
pp. 3657-3661 ◽  
Author(s):  
Michael D. Island ◽  
Xaioling Cui ◽  
John W. Warren
Keyword(s):  
Escherichia Coli ◽  
Bladder Epithelium ◽  
Cell Monolayers ◽  
E Coli ◽  
Cytotoxic Necrotizing Factor ◽  
Bladder Cell ◽  
Bladder Cells ◽  
Vitro Model ◽  
Cytotoxic Necrotizing Factor 1

ABSTRACT We hypothesized that Escherichia coli cytotoxic necrotizing factor 1 (CNF1) might impair migration or proliferation of bladder cells and could potentially interfere with repair of the bladder epithelium. Using experimentally wounded human T24 bladder epithelial cell monolayers as an in vitro model, we found that both the number of T24 cells and the maximum distance they migrated into wounded regions was significantly decreased by bacterial extracts containingE. coli CNF1.

scholarly journals Cytotoxic Necrotizing Factor 1 Prevents Apoptosis via the Akt/IκB Kinase Pathway: Role of Nuclear Factor-κB and Bcl-2

2007 ◽  
Vol 18 (7) ◽  
pp. 2735-2744 ◽  
Author(s):  
Alessandro Giamboi Miraglia ◽  
Sara Travaglione ◽  
Stefania Meschini ◽  
Loredana Falzano ◽  
Paola Matarrese ◽  
...  
Keyword(s):  
Rho Gtpase ◽  
Nuclear Factor Κb ◽  
Ultraviolet B ◽  
Bacterial Toxin ◽  
Nuclear Factor ◽  
Mitochondrial Network ◽  
Cytotoxic Necrotizing Factor ◽  
Protein Toxin ◽  
Iκb Kinase ◽  
Cytotoxic Necrotizing Factor 1

Cytotoxic necrotizing factor 1 (CNF1) is a protein toxin produced by some pathogenic strains of Escherichia coli that specifically activates Rho, Rac, and Cdc42 GTPases. We previously reported that this toxin prevents the ultraviolet-B–induced apoptosis in epithelial cells, with a mechanism that remained to be defined. In this work, we show that the proteasomal degradation of the Rho GTPase is necessary to achieve cell death protection, because inhibition of Rho degradation abolishes the prosurvival activity of CNF1. We hypothesize that Rho inactivation allows the activity of Rac to become dominant. This in turn leads to stimulation of the phosphoinositide 3-kinase/Akt/IκB kinase/nuclear factor-κB prosurvival pathway and to a remarkable modification in the architecture of the mitochondrial network, mainly consisting in the appearance of elongated and interconnected mitochondria. Importantly, we found that Bcl-2 silencing reduces the ability of CNF1 to protect cells against apoptosis and that it also prevents the CNF1-induced mitochondrial changes. It is worth noting that the ability of a bacterial toxin to induce such a remodeling of the mitochondrial network is herein reported for the first time. The possible pathophysiological relevance of this finding is discussed.

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