Fibronectinbinding

Fibronectin-binding refers to the interaction between proteins that bind to fibronectin, a high-molecular-weight glycoprotein of the extracellular matrix and plasma. In biological contexts, fibronectin binding is most extensively studied as a host–pathogen adhesion mechanism, wherein microbial surface proteins specifically recognize and bind fibronectin to attach to host tissues and facilitate invasion or colonization.

In bacteria, fibronectin-binding proteins (FnBPs) are cell-surface adhesins commonly found in Gram-positive species such as Staphylococcus aureus and Streptococcus pyogenes. These proteins often contain repeated domains that mediate high-affinity binding to fibronectin. Many FnBPs are anchored to the cell wall by sortase-dependent motifs (for example, LPXTG) and use their fibronectin-binding regions to attach bacteria to fibronectin-coated surfaces or to tissue matrices. The bound fibronectin can act as a bridge to host cell integrins, particularly alpha5beta1, enabling internalization of bacteria into non-phagocytic cells and promoting invasive disease. FnBPs may also contribute to biofilm formation and tissue tropism.

The binding interaction typically involves recognition of specific fibronectin domains, including regions containing the RGD motif in the cell-binding domain, though bacterial FnBPs may engage fibronectin through alternative sites as well. Fibronectin binding can enhance adherence to endothelial and epithelial surfaces and support dissemination during infection. Beyond pathogens, fibronectin-binding capabilities are also relevant in tissue engineering contexts where controlled cell adhesion and matrix interactions are important.

Clinical relevance includes consideration of FnBP–fibronectin interactions as potential targets for anti-adhesion therapies or vaccines aimed at reducing bacterial adherence and invasion. See also fibronectin, integrins, and bacterial adhesins.