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- Title
EspO1-2 Regulates EspM2-Mediated RhoA Activity to Stabilize Formation of Focal Adhesions in Enterohemorrhagic <i>Escherichia coli</i>-Infected Host Cells.
- Authors
Morita-Ishihara, Tomoko; Miura, Masashi; Iyoda, Sunao; Izumiya, Hidemasa; Watanabe, Haruo; Ohnishi, Makoto; Terajima, Jun
- Abstract
Enterohemorrhagic Escherichia coli (EHEC) Sakai strain encodes two homologous type III effectors, EspO1-1 and EspO1-2. These EspO1s have amino acid sequence homology with Shigella OspE, which targets integrin-linked kinase to stabilize formation of focal adhesions (FAs). Like OspE, EspO1-1 was localized to FAs in EHEC-infected cells, but EspO1-2 was localized in the cytoplasm. An EHEC ΔespO1-1ΔespO1-2 double mutant induced cell rounding and FA loss in most of infected cells, but neither the ΔespO1-1 nor ΔespO1-2 single mutant did. These results suggested that EspO1-2 functioned in the cytoplasm by a different mechanism from EspO1-1 and OspE. Since several type III effectors modulate Rho GTPase, which contributes to FA formation, we investigated whether EspO1-2 modulates the function of these type III effectors. We identified a direct interaction between EspO1-2 and EspM2, which acts as a RhoA guanine nucleotide exchange factor. Upon ectopic co-expression, EspO1-2 co-localized with EspM2 in the cytoplasm and suppressed EspM2-mediated stress fiber formation. Consistent with these findings, an ΔespO1-1ΔespO1-2ΔespM2 triple mutant did not induce cell rounding in epithelial cells. These results indicated that EspO1-2 interacted with EspM2 to regulate EspM2-mediated RhoA activity and stabilize FA formation during EHEC infection.
- Subjects
FOCAL adhesions; ESCHERICHIA coli O157:H7; AMINO acid sequence; SEQUENCE alignment; INTEGRINS; NUCLEOTIDE exchange factors; STRESS fibers (Cytology); GENETIC mutation
- Publication
PLoS ONE, 2013, Vol 8, Issue 2, p1
- ISSN
1932-6203
- Publication type
Article
- DOI
10.1371/journal.pone.0055960