Cells were grown in glass chambers (Thermo Fisher Scientific). One hour before imaging, the medium was changed to prewarmed Leibovitz’s L‐15 medium (Thermo Fisher Scientific) supplemented with 20% FBS and 20 mM HEPES, pH 7.0. Recordings were made in a temperature‐controlled incubator at 37°C, as described previously.11 (link), 17 (link), 18 (link), 19 (link), 20 (link) Z‐series of three sections in 3‐µm increments were captured every 15 minutes. Image stacks were projected. Images were collected with an Olympus IX‐71 inverted microscope controlled by DeltaVision softWoRx (Cytiva) using a ×20 0.75 NA UPlanSApo objective lens (Olympus).