How actin/myosin crosstalks guide the adhesion, locomotion and polarization of cells

Directed cell locomotion is driven by cyclic progression of the front and retraction of the end regulated by actin microtubule (MT) crosstalk. Adhesion domains (ADs) formed about integrin clusters act as biochemical steering and force generating centers. Their function is controlled in a Ca++- and force-dependent way by quaternary complexes of actin, IQGAP, calmodulin, and microtubule. The rhythmic cell progression is determined by the dynamic antagonism between the GTPases Rac-1 and Rho-A. The retraction is mediated by protease (P)-activated by Ca++ release from ER stores which mediates the dismantling and retraction of rearmost ADs by activation of RhoA and inhibition of Rac-1 in the cell-tissue adhesion zone.151