Fig. 1.

Sketch of the mechano-kinetic model for a cell inside a micropipette. (A) A cell is drawn inside a micropipette (of radius R_p) by a pressure difference, forming a cylindrical tongue with an hemispherical cap (L is the length of the tongue and the velocity of its front). The PM is in green and the actin cortex in red. (B) The cortex is a gel of cross-linked actin filaments (red), of mesh size ξ, and contractile myosin microfilaments (orange). (C) The cortical actin layer (of thickness h) is constantly being renewed by polymerization (of velocity v_p) near the membrane and depolymerization (with a rate k_d), leading to treadmilling. An element of cortex (of initial length l when it is formed at the PM) is stretched by the extension of the tongue and reaches a length l + δl before being depolymerized. (D) The cortex is attached to the PM by dynamical molecular linkers. (E) Linkers have association and dissociation rates dependent on their energy landscape (black curve). When a force is applied on the bond, its energy landscape and associated rates are modified (red curve).