Formin-mediated actin polymerization displaces septin from CEV. (A) Immunoblot analysis confirming that FHOD1 siRNA treatment of HeLa cells for 72 h leads to loss of FHOD1. The graphs show the percentage of CEV recruiting SEPT7 and inducing actin tails in the presence (Allstar) or absence of FHOD1. (B) Representative images panels from live cell imaging showing that GFP-FHOD1 is not recruited to CEV when septins are displaced from the virus. The time in seconds is indicated. Bar, 1 µm. See Video 9. (C) Images showing the association of SEPT7 with CEV in WR-infected HeLa cells treated with cytochalasin D to block actin polymerization or SMIFH2 to inhibit formins. The graph shows quantification of septin recruitment during the indicated drug treatments. Bars: (main images) 5 µm; (insets) 2 µm. (D) Quantification of the impact of inhibiting formins (SMIFH2), dynamin (MiTMAB) or both proteins on the % of CEV recruiting SEPT7 and inducing actin tails. (E) The graph shows the effect of inhibiting formins with SMIFH2 on the percentage of CEV recruiting dyn II. (F) Quantification of the percentage of CEV recruiting SEPT7 in the presence (+/+) or absence (−/−) of dynamin with and without (CTRL) SMIFH2 treatment. All error bars represent SEM from three independent experiments in which >900 CEVs were analyzed across 30 cells. **, P < 0.01; ***, P < 0.001.