Disease relevance of ECs4554

• EspB from enterohaemorrhagic Escherichia coli is a natively partially folded protein [1].
• This structural feature of EspB may be advantageous when EspB interacts with various biomolecules during the bacterial infection of host cells [1].
• However, RDEC-1 EspB was identical to that of enterohemorrhagic E. coli serotype O26 [2].
• Cells expressing EspB were significantly impaired in their ability to support invasion by EPEC and Salmonella typhimurium [3].
• Intimin from enteropathogenic Escherichia coli restores murine virulence to a Citrobacter rodentium eaeA mutant: induction of an immunoglobulin A response to intimin and EspB [4].

High impact information on ECs4554

• Two enteropathogenic Escherichia coli type III secreted proteins, EspA and EspB, are virulence factors [5].
• Here, we describe a novel EspA-containing filamentous organelle that is present on the bacterial surface during the early stage of A/E lesion formation, forms a physical bridge between the bacterium and the infected eukaryotic cell surface and is required for the translocation of EspB into infected epithelial cells [6].
• Sustained NF-kappaB activity was observed either using an isogenic mutant lacking EspB or after gentamicin-based killing of STEC after allowing bacterial attachment [7].
• However, EspB expression in an rcsB deletion mutant increased compared with wild type, suggesting that RcsB negatively regulates LEE gene expression and that active RcsB protein is present under normal growth conditions [8].
• Nevertheless, binding of EspA filaments to the host cell membranes occurred even in the absence of EspB [9].

Chemical compound and disease context of ECs4554

• The role of pyridoxal phosphate in the function of EspB, a protein secreted by enteropathogenic Escherichia coli [10].
• Detection of EspB using reversed passive latex agglutination: application to determination of enteropathogenic Escherichia coli [11].

Biological context of ECs4554

• The structural properties of EspB, a virulence factor of the Escherichia coli O157 type III secretion system, were characterized [1].
• These results indicate that EspB is both translocated and required for protein translocation by EPEC [12].
• One set is dependent on EPEC proteins secreted by the type III secretion pathway (EspA and EspB) which induces Hp90 tyrosine phosphorylation and dephosphorylation of host phosphotyrosine proteins [13].
• To determine the effect of intracellular EspB on the host cell cytoskeleton, we transfected HeLa cells with a plasmid containing the espB gene under the control of an inducible eukaryotic promoter [3].
• Analysis of the function of enteropathogenic Escherichia coli EspB by random mutagenesis [14].

Anatomical context of ECs4554

• We have demonstrated that contact of EPEC with HeLa cells is associated with the induction of production and secretion of EspB [12].
• We found that some DAEC strains contain homologues of the locus of enterocyte effacement (LEE) pathogenicity island and secrete EspA, EspB and EspD proteins necessary for the formation of the attaching and effacing (A/E) lesions [15].
• EspA is a structural protein and the major component of a large transiently expressed filamentous surface organelle that forms a direct link between the bacterium and the host cell, whereas EspD and EspB seem to form the mature translocation pore [16].
• Besides its function in pore formation, EspB has been found in the cytosol and implicated to function as an effector protein [17].
• EPEC adhering to CMT-93 cells induced far less secretion of EspB, or reorganization of F-actin in the host CMT-93 cells, than did EPEC adhering to Caco-2 cells [18].

Associations of ECs4554 with chemical compounds

• 0. Destabilization of EspB at low pH was shown by urea-unfolding transitions, monitored by far-UV CD spectroscopy [1].
• An increase in the fluorescence intensity of 8-anilinonaphthalene-1-sulfonate was observed at pH 2.0 in the presence of EspB, whereas no such increase in fluorescence was observed at pH 7 [1].
• The results of these studies do not support a role for pyridoxal phosphate in EspB function [10].
• This mutant is incapable of attaching and effacing, of secreting EspA and EspB and of inducing tyrosine phosphorylation of host cell proteins [19].
• Plasmids containing cloned espB, in which the lysine residue conserved in the motif was substituted with either an arginine or methionine residue, remained capable of complementing an espB deletion mutant to restore EspB function [10].

Analytical, diagnostic and therapeutic context of ECs4554

• We used cellular fractionation and confocal laser scanning microscopy to determine the cellular location of EspB during infection of HeLa cells [20].
• To determine the actual role of EspB in this process, we tried to identify the EspB binding partner of the host cell protein, using a yeast two-hybrid assay, and obtained a cytoskeletal-associated protein, alpha-catenin [21].
• Pyridoxal phosphate was not found by fluorometry in concentrated supernatants of EPEC cultures that contain EspB [10].
• To define the secretion determinants, different fragments of EspB were fused in recombinant proteins and the proteins secreted into media analyzed by Western blot [22].
• Attaching and effacing Escherichia coli (AEEC) strains isolated from diarrhoeic lambs and goat kids were characterized for intimin (eae) and EspB (espB) gene subtypes by PCR and sequencing, and for genetic relatedness by PFGE [23].

References