Fig. 5. Colocalization of keratin particles and microtubules (Movie 5). PtK2 cells were transfected with EGFP-K5 and EYFP–tubulin. Cells were grown to confluence, three days after transfection. Panels A-H show the path of two fast-moving F particles (white and blue arrows). In total, 34 images were acquired with a 5 second time-lapse interval (see Movie 5). Six Z sections with a 100 nm spacing were taken per time-point and subsequently analysed using the edge enhancement tool (represents filaments as tubes rather than lines) of softWorX 2.50 software. The resulting images for section 1 are shown in A-H. Two keratin particles (in green, indicated by the white and blue arrows) follow one another along the same path of a microtubule (red, positioned slightly out of the focal plane; see Movie 5).