Figure 1.

Schematic diagram of a cell rolling under shear flow. Adhesive bond formation takes place in the formation zone, whereas bond breakage occurs in the breakage zone. Microvilli with receptors on their tips extend in the process (inset) and detach after all bonds at the tip dissociate. A three-element viscoelastic model (inset) describes microvillus rheology, where one of the springs changes its state at a threshold force enabling transition from a viscoelastic to a viscous behavior.