Figure 9.

A physical model for contractile ring dynamics. (A) Full scalability based on contractile unit hypothesis (ϕ = 1, λ = 0). (B) Super scalability due to scalable initial myosin density only (ϕ₀ = 1, ζ = 0.5, λ = 0). (C) Size-dependent actin turnover leads to either full scalability (solid lines, ϕ₀ = 1, ζ = 0) or super scalability (dashed lines, ϕ₀ = 1, ζ > 0). (D) Size-independent actin turnover leads to partial scalability, as shown in experimental N. crassa data (symbols). Model (lines) uses fitted parameters (ζ = 0.3 ± 0.05, ϕ₀ = 0.00085 ± 0.00015 s⁻¹ [including uncertainty estimates], and λ = 0.052 ± 0.012 µm/s).