Figure 3: Syntabulin and PICK1 comigrate along microtubule structures.

(A) COS7 cells were transfected with GFP-Syntabulin and RFP-PICK1 and examined under a live-imaging microscope with both green- and red-fluorescent channels; images were collected for 2 min at 2-s intervals. The “snapshot” shows the colocalization of PICK1 and syntabulin at a single time point, and the Z-projection shows the movement trajectories of PICK1 and syntabulin over 2 min. The merged image shows that the trajectory of PICK1 overlapped with that of syntabulin, which was juxtaposed to syntabulin-induced microtubule bundles. (B) PICK1 and syntabulin vesicle movement at different time point in the cell presented in (A). Arrowheads indicate the position of a single PICK1-syntabulin-containing vesicle at 10-s intervals. The kymograph also shows the overlapped movement trace of PICK1 and syntabulin. (C) PICK1-syntabulin-containing vesicles move in a microtubule-dependent but not actin-dependent manner. The snapshots show the original position of PICK1 and syntabulin proteins before drug treatment, and the Z-projection shows the movement trajectories of both proteins before and after drug treatment. Noco, nocodazole; CytoD, cytochalasin D. Scale bar = 10 μm in all panels.