Homologous Superfamily

Translocated intimin receptor, central domain superfamily (IPR037003)

Short name: Tir_central_sf

Overlapping entries


Secretion of virulence factors in Gram-negative bacteria involves transportation of the protein across two membranes to reach the cell exterior. There have been four secretion systems described in animal enteropathogens, such as Salmonella and Yersinia, with further sequence similarities in plant pathogens like Ralstonia and Erwinia [PMID: 9618447].

The type III secretion system is of great interest, as it is used to transport virulence factors from the pathogen directly into the host cell and is only triggered when the bacterium comes into close contact with the host. The protein subunits of the system are very similar to those of bacterial flagellar biosynthesis. However, while the latter forms a ring structure to allow secretion of flagellin and is an integral part of the flagellum itself [PMID: 9618447], type III subunits in the outer membrane translocate secreted proteins through a channel-like structure.

Exotoxins secreted by the type III system do not possess a secretion signal, and are considered unique for this reason [PMID: 9618447]. Enteropathogenic and entero-haemorrhagic Escherichia coli secrete the bacterial adhesion mediation molecule intimin [PMID: 10835344], which targets the translocated intimin receptor (Tir). Tir is secreted by the bacteria and is embedded in the target cell's plasma membrane [PMID: 10835344]. This facilitates bacterial cell attachment to the host.

This entry represents the Tir intimin-binding domain superfamily which is needed to bind intimin and support the predicted topology for Tir, with both N- and C-terminal regions in the mammalian cell cytosol [PMID: 11207537].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0005515 protein binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.