Science STKE has a nice perspective up recently on the flux at focal adhesions. For newbies, focal adhesions are plaque-like structures that form contact points between cultured adherent cells and the surface to which they adhere. These sites act as ‘anchors’ for maintaining cell shape and generating traction required for cell movement.
Yu-li Wang’s brief review covers the current understanding of dynamic protein interactions at focal adhesions, and attempts to define the mechanical basis for these supramolecular “machines.” As his title suggests, these adhesion plaques appear to function as a combination of a slippage clutch, a mechanical gauge, and a signal depot.
Differential retrograde movements of focal adhesion proteins as a result of partial unraveling of a protein complex at focal adhesions. The complex serves as a connector between actin filaments (orange fiber) and integrins (double barrels), which bind to ECM (Brown ties on bottom). Contractile forces (red arrow) cause the complex to unravel and extend. Components located close to actin filaments (gray star) move for a longer distance than do components located close to integrins (pink oval).
- Wang YL. Flux at focal adhesions: slippage clutch, mechanical gauge, or signal depot. Sci STKE. 2007 Mar 13;2007(377):pe10.