The University of Chicago   The Mrksich Laboratory


Focal Adhesion Structure and Dynamics

We have applied the tailored substrates to study the focal adhesion structures that link the cell to the extracellular matrix. Focal adhesions (FAs) are large multi-protein complexes that assemble at the cell membrane at clusters of integrin receptors. The FAs serve both a structural role in linking the cell to the matrix and a signaling role in directing many cellular activities. The importance of FAs has generated a significant research effort, yet the complexity and heterogeneity of these structures has made direct studies difficult. Our program is investigating the role of ECM ligands in influencing focal adhesion structure and dynamics. In one example, we compared cell adhesion on substrates presenting either a low affinity or high affinity ligand for integrin receptors and found that adhesion to the higher affinity ligand resulted in cells having smaller, and twice as many focal adhesions.78 This work pointed to a nucleation/growth model to understand the formation of focal adhesions. We are also imaging the dynamics of focal adhesions in live cells-using a GFP-paxillin transfect-to understand the effect of ligand-receptor affinity on FA dynamics.