Focal Adhesion - Morphology

Morphology

Connection between focal adhesions and proteins of the extracellular matrix generally involves integrins. Integrins bind to extra-cellular proteins via short amino acid sequences, such as the R-G-D sequence motif (found in proteins such as fibronectin, laminin, or vitronectin), or the DGEA and GFOGER motifs found in collagen. Integrins are heterodimers which are formed from one beta and one alpha subunit. These subunits are present in different forms, which differ in their specificity and affinity to the different ECM proteins. Within the cell, the intracellular domain of integrin binds to the cytoskeleton via adapter proteins such as talin, α-actinin, filamin and vinculin. Many other intracellular signalling proteins, such as focal adhesion kinase, bind to and associate with this integrin-adapter protein–cytoskeleton complex, and this forms the basis of a focal adhesion.