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0  structures 104  species 0  interactions 135  sequences 3  architectures

Family: Tir_receptor_N (PF07490)

Summary: Translocated intimin receptor (Tir) N-terminus

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Translocated intimin receptor (Tir) N-terminus Provide feedback

Intimin and its translocated intimin receptor (Tir) are bacterial proteins that mediate adhesion between mammalian cells and attaching and effacing (A/E) pathogens. A unique and essential feature of A/E bacterial pathogens is the formation of actin-rich pedestals beneath the intimately adherent bacteria and localised destruction of the intestinal brush border. The bacterial outer membrane adhesin, intimin, is necessary for the production of the A/E lesion and diarrhoea. The A/E bacteria translocate their own receptor for intimin, Tir, into the membrane of mammalian cells using the type III secretion system. The translocated Tir triggers additional host signalling events and actin nucleation, which are essential for lesion formation [1]. This family represents the Tir N-terminal domain which is involved in Tir stability and Tir secretion [2].

Literature references

  1. Luo Y, Frey EA, Pfuetzner RA, Creagh AL, Knoechel DG, Haynes CA, Finlay BB, Strynadka NC; , Nature 2000;405:1073-1077.: Crystal structure of enteropathogenic Escherichia coli intimin-receptor complex. PUBMED:10890451 EPMC:10890451

  2. de Grado M, Abe A, Gauthier A, Steele-Mortimer O, DeVinney R, Finlay BB; , Cell Microbiol 1999;1:7-17.: Identification of the intimin-binding domain of Tir of enteropathogenic Escherichia coli. PUBMED:11207537 EPMC:11207537


External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR022633

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 [PUBMED: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 [PUBMED: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 [PUBMED:9618447]. Enteropathogenic and entero- haemorrhagic Escherichia coli secrete the bacterial adhesion mediation molecule intimin [PUBMED:10835344], which targets the translocated intimin receptor, Tir. Tir is secreted by the bacteria and is embedded in the target cell's plasma membrane [PUBMED:10835344]. This facilitates bacterial cell attachment to the host.

Domain organisation

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Alignments

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Full
(135)
Representative proteomes NCBI
(78)
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  Seed
(4)
Full
(135)
Representative proteomes NCBI
(78)
Meta
(0)
RP15
(0)
RP35
(0)
RP55
(1)
RP75
(1)
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  Seed
(4)
Full
(135)
Representative proteomes NCBI
(78)
Meta
(0)
RP15
(0)
RP35
(0)
RP55
(1)
RP75
(1)
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You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.

Pfam alignments:

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Curation and family details

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Seed source: PRINTS
Previous IDs: none
Type: Family
Author: Griffiths-Jones SR, Moxon SJ
Number in seed: 4
Number in full: 135
Average length of the domain: 256.50 aa
Average identity of full alignment: 76 %
Average coverage of the sequence by the domain: 48.76 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 25.0 25.0
Trusted cut-off 31.0 31.0
Noise cut-off 21.7 19.8
Model length: 266
Family (HMM) version: 6
Download: download the raw HMM for this family

Species distribution

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