Invasin

[4] Invasin is a small membrane bound protein that enables the infiltration of cultured mammalian cells by enteric bacteria.

More precisely, it forms a robust attachment to the α5β1 integrin, typically employed by fibronectin, exhibiting roughly 100 times greater strength.

[7] Yersinia pseudotuberculosis, a Gram-negative bacterium and zoonotic pathogen, is accountable for various diseases, spanning mild diarrhea, enterocolitis, lymphatic adenitis, to enduring local inflammation.

This infection presents as acute diarrhea, mesenteric adenitis, terminal ileitis, and pseudoappendicitis, occasionally progressing to sepsis.

The pathogen can disseminate within pig herds, contaminating pork products like neck trimmings, tongue, and tonsils, potentially spreading to other meat cuts during the slaughtering process.

The disulfide bond between Cys906 and Cys982, a conserved feature in all CTLDs, is essential for integrin binding, likely due to its role in ensuring proper folding.

This particular invasin segment bears a resemblance to the fibronectin synergy region in Fn-III 9, crucial for optimal α5β1 integrin-dependent cell spreading.

Assuming that the membrane-associated section of invasin also forms a β-barrel, with the cell-binding region extending approximately 180 Å from the bacterial surface, it is positioned to engage host cell integrins.

Interestingly, these integrins do not play a role in particle ingestion; instead, they are involved in processes like adhesion to the extracellular matrix, interactions with cell surfaces, migration, and differentiation.

Unlike traditional parenteral routes, the oral approach is non-invasive, promoting increased patient compliance and simplified dosing.

The invasin-mediated uptake into mammalian cells involves a clustering model. Multivalent invasin induces integrin clustering by simultaneously binding to multiple integrin heterodimers. This process, dependent on ligand binding and β1-integrin multimerization, leads to the association of various cell signaling molecules, triggering the involvement of additional signaling and cytoskeletal proteins. [ 12 ]