TccP2 of O157:H7 and non-O157 enterohemorrhagic Escherichia coli (EHEC): challenging the dogma of EHEC-induced actin polymerization.
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 and enteropathogenic E. coli (EPEC) trigger actin polymerization at the site of bacterial adhesion by inducing different signaling pathways. Actin assembly by EPEC requires tyrosine phosphorylation of Tir, which subsequently binds the host adaptor protein Nck. In contrast, Tir(EHEC O157) is not tyrosine phosphorylated and instead of Nck utilizes the bacterially encoded Tir-cytoskeleton coupling protein (TccP)/EspF(U), which mimics the function of Nck. tccP is carried on prophage CP-933U/Sp14 (TccP). Typical isolates of EHEC O157:H7 harbor a pseudo-tccP gene that is carried on prophage CP-933 M/Sp4 (tccP2). Here we report that atypical, beta-glucuronidase-positive and sorbitol-fermenting, strains of EHEC O157 harbor intact tccP and tccP2 genes, both of which are secreted by the LEE-encoded type III secretion system. Non-O157 EHEC strains, including O26, O103, O111, and O145, are typically tccP negative and translocate a Tir protein that encompasses an Nck binding site. Unexpectedly, we found that most clinical non-O157 EHEC isolates carry a functional tccP2 gene that encodes a secreted protein that can complement an EHEC O157:H7 DeltatccP mutant. Using discriminatory, allele-specific PCR, we have demonstrated that over 90% of tccP2-positive non-O157 EHEC strains contain a Tir protein that can be tyrosine phosphorylated. These results suggest that the TccP pathway can be used by both O157 and non-O157 EHEC and that non-O157 EHEC can also trigger actin polymerization via the Nck pathway.
Ogura
Yoshitoshi
Y
Division of Cell and Molecular Biology, Flowers Building, Imperial College London, London SW7 2AZ, United Kingdom.
Ooka
Tadasuke
T
Whale
Andrew
A
Garmendia
Junkal
J
Beutin
Lothar
L
Tennant
Sharon
S
Krause
Gladys
G
Morabito
Stefano
S
Chinen
Isabel
I
Tobe
Toru
T
Abe
Hiroyuki
H
Tozzoli
Rosangela
R
Caprioli
Alfredo
A
Rivas
Marta
M
Robins-Browne
Roy
R
Hayashi
Tetsuya
T
Frankel
Gad
G
D000199:Actins / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D015153:Blotting, Western; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004847:Epithelial Cells / Q000737:chemistry / Q000382:microbiology; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D019453:Escherichia coli O157 / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D017353:Gene Deletion; D005816:Genetic Complementation Test; D006367:HeLa Cells; D006801:Humans; D007150:Immunohistochemistry; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D037521:Virulence Factors / Q000235:genetics*
D000199:Actins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D011956:Receptors, Cell Surface; C526042:TccP2 protein, E coli; C109287:Tir protein, E coli; D037521:Virulence Factors; C505370:tccP protein, E coli