Movie 1

Connections were examined by time-lapse microscopy using a fluorescent LifeAct lentivirus, allowing simultaneous observation of both Differential Interference Contrast optics (DIC, left) and polymerized actin (right). Transient contacts (arrowheads) and stable connection (arrow) are noted. Insets, high magnification time frames for transient contacts and stable connections. For transient contacts, the frame showing the contact and the frame immediately following (and lacking the contact) are shown for clarity; for stable connections the first frame showing the connection is shown. Scale bar, 25 μm (lower right); time, hrs:mins (lower left).