Figure 5.

Numerical solutions for the total number of α-catenin dimers in the cell as a function of different parameters when the cadherin-catenin system is treated as a zero-dimensional reaction system. In this limit, the contact inhibition mechanism is based on a larger degradation rate on the membrane ($r_{\beta }^{\text{m},\text{d}}$ = 10⁻² s⁻¹) than in the cytosol (r_β = 10⁻³ s⁻¹). The α-catenin degradation rate, r_α, is also assumed to be small (10⁻³ s⁻¹). The total production rates of α-catenin and β-catenin are equal to 7.5 × 10³ s⁻¹ and 14 × 10³ s⁻¹. Protein-protein reaction rates are 10⁻³ s⁻¹, and on and off rates of the β-catenin protein complex to the cell membrane are $k_{\beta }^{\text{on}}$ = $k_{\beta }^{\text{off}}$ = 0.1 s⁻¹. Note that for r_β > $r_{\beta }^{\text{m},\text{d}}$, the switch is reversed.