Recruitment and membrane interactions of host cell proteins during attachment of enteropathogenic and enterohaemorrhagic Escherichia coli

Abstract

EPEC (enteropathogenic Escherichia coli) and EHEC (enterohaemorrhagic Escherichia coli) are attaching and effacing pathogens frequently associated with infectious diarrhoea. EPEC and EHEC use a T3SS (type III secretion system) to translocate effectors that subvert different cellular processes to sustain colonization and multiplication. The eukaryotic proteins NHERF2 (Na(+)/H(+) exchanger regulatory factor 2) and AnxA2 (annexin A2), which are involved in regulation of intestinal ion channels, are recruited to the bacterial attachment sites. Using a stable HeLa-NHERF2 cell line, we found partial co-localization of AnxA2 and NHERF2; in EPEC-infected cells, AnxA2 and NHERF2 were extensively recruited to the site of bacterial attachment. We confirmed that NHERF2 dimerizes and found that NHERF2 interacts with AnxA2. Moreover, we found that AnxA2 also binds both the N- and C-terminal domains of the bacterial effector Tir through its C-terminal domain. Immunofluorescence of HeLa cells infected with EPEC showed that AnxA2 is recruited to the site of bacterial attachment in a Tir-dependent manner, but independently of Tir-induced actin polymerization. Our results suggest that AnxA2 and NHERF2 form a scaffold complex that links adjacent Tir molecules at the plasma membrane forming a lattice that could be involved in retention and dissemination of other effectors at the bacterial attachment site.

Clumping factor A of Staphylococcus aureus interacts with AnnexinA2 on mammary epithelial cells

“…The expression of AnnexinA2 on the cell surface plays an important role in cell-cell interactions32. Furthermore, it has been shown to be the interacting partner for attachment of various bacteria to epithelial cells (for example, Pseudomonas auroginosa 33, E. coli 34, and Salmonella typhymurium 35). However, contrary to the study published by Jolly et al 35,.…”

The Annexin A2/p11 complex is required for efficient invasion ofSalmonella Typhimurium in epithelial cells

“…Tir, which is required for pedestal formation, binds directly to the C-terminal region of AnxA2 and recruits it to the site of adherence via an actin-independent process (Munera et al, 2012). Also associated with AnxA2 at the EPEC attachment site is NHERF2 (Na + /H + exchange regulatory factor 2) and it has been proposed that AnxA2 and NHERF2 may form a scaffold complex involved in the retention and dissemination of other effectors at the attachment site (Munera et al, 2012).…”

Intimate host attachment: enteropathogenic and enterohaemorrhagicEscherichia coli

“…cortactin, talin ezrin, annexin) as well as T3SS effectors (e.g. Map, EspH, EspF) are recruited to the pedestal structure and it is possible that within the pedestals these components are organized in a specific architecture that allows a special and temporal control of effector functions (Munera et al, 2012).…”