Prototypical model of cell polarization.

Abstract

<p>A system of receptors transduces an external distribution of chemotactic cues into an internal distribution of activated enzymes , which catalyze the switch of a signaling molecule from an unactivated state to an activated state . A counteracting enzyme transforms the state back into . The network contains a couple of amplifying feedback loops: the signaling molecule activates and acvivates . The signaling molecules , are permanently bound to the cell surface and perform diffusive motions on it, while the , enzymes are free to shuttle between the cytosolic reservoir and the membrane. The result of the polarization process is the formation of separate domains with -rich patches and, respectively, -rich patches.</p