Fig. 6: Only active tethering promotes membrane/actin cytoskeleton remodeling.
From: An active tethering mechanism controls the fate of vesicles
a Membrane expansion induced by Exo70 optogenetics using the CRY2-CIB system. TIRFM of TfRc-pH in a typical Exo70 optogenetics cell. A crop of a peripheral region (rectangle) shows membrane expansion (gallery, right) during activation. The cell was activated at 2 Hz with 100-ms pulses of 488-nm light (2.6 W/cm2). b Time-course of membrane expansion. n = 11 cells for both + CIB and – CIB. Mean ± SEM. Note the initial retraction caused by light during the first 5 s (dashed box). c Membrane expansion only occurs when active tethering is promoted in cells that express CIB optogenetic bait. Expansion (red)/retraction (blue) map of cells after 4 min. d Quantification of displacement. n = 11 cells for each condition. Mean ± SEM (*P = 0.046, ***P = 0.0025, NS = not significant, two-tailed Student’s t-test). e Actin remodeling during Exo70 optogenetics visualized with Lifeact-GFP. Dashed outline, cell shape after 4-min activation (left). Image sequence of filopodia elongation in areas outlined by cyan rectangles (right). Arrows and arrowheads, pre-existing and new filopodia, respectively.
