Figure 7.

The local stiffening induced by myosin II accumulation reduces the energy barrier and critical radius for fusion pore formation. The energy penalty changes with the pore radius at different area strains for α = 2 nm (a), 0 nm (d), −0.4 nm (h) when the stiffening effect K_memΔε = 1.5 nN µm⁻¹ is considered. The energy barrier $\mathrm{\Delta }{E}_{\mathrm{pore}}^{\ast }$ for the cases in (a), (d) and (h) is plotted in (b), (e) and (i), respectively. The critical radius $r_{\mathrm{pore}}^{\ast }$ for the cases in (a), (d) and (h) is plotted in (c), (f) and (j), respectively. For all cases, λ⁰ = 10 pN and K_mem = 100 nN µm⁻¹. (Online version in colour.)