View source for Intimin

{{Infobox protein family
| Symbol = Intimin_C
| Name = Intimin C-type lectin domain
| image = PDB 1e5u EBI.jpg
| width =
| caption = nmr representative structure of intimin-190 (int190) from enteropathogenic e. coli
| Pfam = PF07979
| Pfam_clan = CL0056
| InterPro = IPR013117
| SMART =
| PROSITE =
| MEROPS =
| SCOP =
| TCDB =
| OPM family =
| OPM protein =
| CAZy =
| CDD =
}}
'''Intimin''' is a [[virulence factor]] ([[Bacterial adhesin|adhesin]]) of [[Pathogenic Escherichia coli|EPEC]] (''e.g.'' ''E. coli'' [[O127:H6]]) and [[Enterohemorrhagic Escherichia coli|EHEC]] (''e.g. E. coli'' [[O157|O157:H7]]) ''[[E. coli]]'' strains. It is an attaching and effacing (A/E) protein, which with other virulence factors is necessary and responsible for [[enteropathogenic E. coli|enteropathogenic]] and [[enterohemorrhagic|enterohaemorrhagic]] [[diarrhoea]].<ref name="pmid16415925">{{cite journal | vauthors = Stevens JM, Galyov EE, Stevens MP | title = Actin-dependent movement of bacterial pathogens | journal = Nature Reviews. Microbiology | volume = 4 | issue = 2 | pages = 91–101 | date = February 2006 | pmid = 16415925 | doi = 10.1038/nrmicro1320 | s2cid = 30946244 | doi-access = free }}</ref>
Intimin is expressed on the bacterial cell surface where it can bind to its receptor [[Tir (receptor)|Tir]] (Translocated intimin receptor).  Tir, and over 25 other bacterial proteins are secreted from attaching and effacing ''E. coli'' directly into the cytoplasm of intestinal epithelial cells by a [[Type three secretion system]].  Once within the cytoplasm of the host cell, Tir is inserted into the plasma membrane, allowing surface exposure and intimin binding.<ref name="pmid16415925" /> Tir-intimin interaction mediates tight binding of [[Enteropathogenic E. coli|enteropathogenic]] and [[enterohaemorrhagic]] ''E.coli'' to the intestinal epithelia, resulting in the formation of effacing lesions on intestinal epithelia.<ref>{{cite journal | vauthors = Jerse AE, Yu J, Tall BD, Kaper JB | title = A genetic locus of enteropathogenic Escherichia coli necessary for the production of attaching and effacing lesions on tissue culture cells | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 87 | issue = 20 | pages = 7839–43 | date = October 1990 | pmc = 54845 | doi=10.1073/pnas.87.20.7839 | pmid=2172966| doi-access = free }}</ref>
The [[secondary structure|structure]] of the [[C-terminal]] [[protein domain|domain]] has been solved and shown to have a C-lectin type of structure.<ref name="pmid10835344">{{cite journal | vauthors = Batchelor M, Prasannan S, Daniell S, Reece S, Connerton I, Bloomberg G, Dougan G, Frankel G, Matthews S | title = Structural basis for recognition of the translocated intimin receptor (Tir) by intimin from enteropathogenic Escherichia coli | journal = The EMBO Journal | volume = 19 | issue = 11 | pages = 2452–64 | date = June 2000 | pmid = 10835344 | pmc = 212744 | doi = 10.1093/emboj/19.11.2452 }}</ref> It is the C-terminal domain that mediates attachment to Tir.
It is a 94 kDa outer membrane protein encoded by ''eae''A gene in the locus of enterocyte effacement (LEE), a 35-Kb pathogenicity island.<ref name="pmid9044273">{{cite journal | vauthors = McDaniel TK, Kaper JB | title = A cloned pathogenicity island from enteropathogenic Escherichia coli confers the attaching and effacing phenotype on E. coli K-12 | journal = Molecular Microbiology | volume = 23 | issue = 2 | pages = 399–407 | date = January 1997 | pmid = 9044273 | doi = 10.1046/j.1365-2958.1997.2311591.x| s2cid = 1403067 | url = http://thewatchers.us/EPA/13/1997-K-12-AE-island.pdf }}</ref> Mutations in the ''eaeA'' gene result in loss of ability to cause A/E lesions, and is required for full virulence in infected volunteers and animal models.<ref name="pmid8376594">{{cite journal | vauthors = Donnenberg MS, Tacket CO, James SP, Losonsky G, Nataro JP, Wasserman SS, Kaper JB, Levine MM | title = Role of the eaeA gene in experimental enteropathogenic Escherichia coli infection | journal = The Journal of Clinical Investigation | volume = 92 | issue = 3 | pages = 1412–7 | date = September 1993 | pmid = 8376594 | pmc = 288285 | doi = 10.1172/JCI116717 }}</ref> The N-terminal domains of intimin from A/E lesion forming pathogens have high homology with each other and to [[invasin]] from ''[[Yersinia pseudotuberculosis]]''  and ''[[Yersinia enterocolitica]]'', whereas the C-terminal domains show less homology.
Antibodies to intimin are present in:
# Immune colostrum from mothers in EPEC endemic areas
# The serum of EPEC/EHEC infected children and EPEC infected volunteers
# Secretions of ''Citrobacter rodentium'' infected mice.
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== References ==
{{reflist|32em}}
== Further reading ==
{{refbegin}}
* {{cite journal | vauthors = Ahmed S, Byrd W, Kumar S, Boedeker EC | title = A directed intimin insertion mutant of a rabbit enteropathogenic Escherichia coli (REPEC) is attenuated, immunogenic and elicits serogroup specific protection | journal = Veterinary Immunology and Immunopathology | volume = 152 | issue = 1–2 | pages = 146–55 | date = March 2013 | pmid = 23084628 | doi = 10.1016/j.vetimm.2012.09.035 }}
{{refend}}
{{InterPro content|IPR013117}}
[[Category:Protein domains]]
[[Category:Virulence factors]]
{{Microbiology-stub}}