Cell Polarity — Cdc42 Turing Instability

Reaction-Diffusion Parameters

Activator diff. Dₐ: 0.01 Inhibitor diff. D_i: 0.5 Production rate a: 0.1 Degradation b: 0.9 Nonlinearity k: 0.2 Reinitialize Add Perturbation

Cdc42 polarity is driven by a Turing (activator-inhibitor) mechanism on the cell membrane. The activator (Cdc42-GTP) self-activates via positive feedback and recruits cytoplasmic Cdc42 while producing an inhibitor that diffuses faster. Slow activator + fast inhibitor → spontaneous symmetry breaking and polar spot formation.