| **Video 1. **The streaming patterns of a control cell with no treatment (linked to the left image of cell A in figure 7). |

| **Video 2. **The streaming patterns of a 3 nM latrunculin B-treated cell (linked to the left image of cell D in figure 7). |

| **Video 3. **A 3-dimensional reconstruction and rotation linked to the first projection in figure 9 of a control cell. |

| **Video 4. **A 3-dimensional reconstruction and rotation linked to the first projection in figure 9 of a cell treated with 2 nM latrunculin B for 20 min before fixation. |