Fig. 6. Dynamin mediates Ω→Ο by surrounding and constricting Ω’s pore.

a F_PH, F₅₃₂, Ω’s pore diameter (d_p), and XZ/Y_fix images showing Ω_p→O. Gray triangle: depol_1s. b F_PH, F₅₃₂, and XZ/Y_fix images showing Ω_np→O. c F_PH, F₅₃₂, Ω’s pore diameter (d_p), and XZ/Y_fix images showing Ω’s pore constriction from visible to non-visible pore (Ω_p→Ω_np). Gray triangle: depol_1s. gray circle: <60 nm. d The rate of pore size decrease during Ω_p→Ω_np (Rate_p, 20–80%, n = 13) and the rate of d_b-p decrease during Λ→Ω (Rate_b-p, 20–80%, n = 22) are similar. Data are presented as mean + SEM. e Inhibition of dynamin reduces Ω→Ο transition: Prob(Ω)_→Ο in control (Ctrl, 513 cells from 168 cultures; 336 bovines), in the presence of dynasore (DnS, 64 cells from 13 cultures; 26 bovines; p = 0.0009) or with overexpressed dynamin 1-K44A (Dyn-K44A, 106 cells from 21 cultures; 42 bovines; p = 0.0018). **p < 0.01; ***p < 0.001 (two-tailed unpaired t-test, compared to Ctrl). Data are presented as mean + SEM. f Dynamin puncta flanked and moved with the constricting pore during Ω_p→Ω_np: F_PH, F_Dyn, Ω_p’s pore size (d_p), the distance between two dynamin puncta flanking the pore (d_Dyn, double arrows), and sampled XZ/Y_fix images of PH/dynamin. Gray circles: <60 nm (STED resolution). g Left: Ω’s d_p and d_Dyn plotted versus time after depol_1s during Ω_p→Ω_np. Each color: one Ω_p→Ω_np transition. Right: reduction of Ω’s d_p (Δd_p) plotted versus reduction of d_Dyn (Δd_Dyn) for each Ω_p→Ω_np transition (each circle: one transition). h Schematic drawing: dynamin mediates Ω→O by surrounding and constricting Ω’s pore. Source data are provided as a Source Data file.