Fibronectin, integrin recognition sequences

Figure 48-3. Schematic representation of fibronectin. Seven functional domains of fibronectin are represented two different types of domain for heparin, cell-binding, and fibrin are shown. The domains are composed of various combinations of three structural motifs (I, II, and III), not depicted in the figure. Also not shown is the fact that fibronectin is a dimer joined by disulfide bridges near the carboxyl terminals of the monomers. The approximate location of the RGD sequence of fibronectin, which interacts with a variety of fibronectin integrin receptors on cell surfaces, is indicated by the arrow. (Redrawn after Yamada KM Adhesive recognition sequences.

Figure 48-4. Schematic representation of a cell interacting through various integrin receptors with collagen, fibronectin, and laminin present in the ECM. (Specific subunits are not indicated.) (Redrawn after Yamada KM Adhesive recognition sequences. J Biol Chem 1991 266 12809.)...

Probably the smallest sequence known to be responsible for receptor recognition is the RGD-tripeptide, initially discovered in fibronectin [143]. However, the specificity of the interaction with different integrins, the counter receptors of RGD sequences on the cell surface, is established by the flanking sequences of the RGD motif and the conformation of the tripeptide. In other words, the presentation of the RGD sequence is important for specific recognition by individual integrins. 

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