Fig. 2. Dynamic movement of a keratin F particle at the cell periphery (Movie 1). Keratinocytes (NEB-1 cells) transfected with the EGFP-K5 construct were filmed three days after transfection. (A) The course of a fast, keratin F particle. The total distance covered by the particle in 10 minutes is 11 µm. (B-G) Reconstruction of the zig-zag movement of the keratin particle (white arrow). The keratin network may be involved in this non-random movement, as a transient stop by the keratin particle during the saltatory movement (see Movie 1). Because of the variable lengths of the pauses, these images are not consecutive frames of the corresponding time-lapse movie. The longest pause in this sequence (C) lasted two and a half minutes (10 frames). The movie sequence contains 41 time-points with a 15 second interval, and 7 Z sections (200 nm spacing) were taken at each time-point; images were obtained from the projection of sections 5 and 6. Bar, 1 µm.