Final answer:
Fibronectin bonds with the αφ5β1 integrin receptor, a vital interaction for cell adhesion to the extracellular matrix (ECM) involving the RGD sequence. This adhesion is critical in tissue development and wound healing, as well as in the structure of focal adhesions, where cytoplasmic proteins like talin connect integrins to the actin cytoskeleton.
Step-by-step explanation:
Integrin Receptors and Fibronectin
The key ligand Fibronectin bonds with the integrin receptor αφ5β1, which is also known as the fibronectin receptor. Integrins are heterodimeric transmembrane receptors that play a crucial role in cell adhesion, binding to extracellular matrix (ECM) proteins such as fibronectin, laminin, and collagens. These interactions are essential for tissue development, cell migration, and the formation of cell junctions during processes like embryogenesis and wound healing. The oligopeptide sequence Arg-Gly-Asp (RGD), found within fibronectin, has been identified as a critical cell-adhesion sequence and is actively employed in biomaterials research for promoting cell attachment to various materials.
Moreover, focal adhesions, which are complex assemblies where cells connect to the ECM, involve integrins. These focal adhesions are stabilized by the binding of various cytoplasmic proteins that connect the integrin receptors to the actin cytoskeleton, with talin playing a vital role in this linkage. This integrin-ECM interaction is dynamic, with integrins existing in both low and high affinity states, and is influenced by the mechanical forces within the cell provided by the cytoskeleton.