Fig. 8. Model of a protruding lamella illustrating how differential retrograde motion of actin and adhesion proteins can be regulated at two levels in the linkage. The actin (green) and
-actinin (orange) are always concomitant. Slippage occurs either (A) proximal to
-actinin through its interaction with one of the components of the linkage complex (shaded molecules) or (B) proximal to the integrins (blue dimers) perhaps at the talin-integrin linkage. (C) Protrusion can occur through polymerization generated forces when both levels of the adhesion complex are engaged.