Supplemental Information s3

Supplemental Information

Movie captions for: “Force-Velocity Curves of Motor Proteins Cooperating In Vivo” Shtridelman et al.

Movie 1: Motion enhanced DIC (MEDIC) movie of the NT2 cell shown in Fig. 1A. Vesicles transported in the upper left, near the filopodia lining the edge of the cell, are visible in this MEDIC movie, but not visible in the corresponding non-motion enhanced DIC movie (Movie 4). Only a portion of the cell’s edge is visible (upper left) because the cell is larger than the field of view (55 µm X 55 µm in this movie and all subsequent movies). The frame number is visible in the lower right, and the frame rate is 8.3 per second. These movies are played back in Windows Media Player (WMP) at a slightly slower than actual speed (29 s of play time vs. 24 s of actual recording time). However, if the fast-forward button is pressed in WMP (the button that looks like “ ” at the end of the seek bar) the movie plays back faster than actual speed, which allows the vesicle transport to be clearly seen. In normal data collection, vesicle transport is clearly seen at actual speed, since the (uncompressed) movies are displayed on a high quality gray scale monitor.

Movie 2: MEDIC movie of NT2 cell. None of the cell’s edge is visible in this movie. During the first ~50 frames, the focus was in the process of being adjusted. The affect of this focusing on the MEDIC movie is more noticeable than the affect on the corresponding non-motion enhanced DIC movie (Movie 5). This is due to the fact that in motion enhancement, a continuously updated background image, created from the average of 8 previous images, is subtracted from each subsequent image.

Movie 3: MEDIC movie of the same NT2 cell as shown in Movie 2. The prominent vesicle in the lower right quadrant that makes a ~90° turn to the right at frame ~80 is the same vesicle shown in Fig. 4A. This prominent vesicle is also easily seen in the corresponding non-motion enhanced DIC movie (Movie 6), as are many other vesicles in this movie and in Movie 2. Thus, MEDIC microscopy is most useful for visualizing smaller, faster vesicles that are not visible with normal DIC microscopy (e.g. most vesicles seen in Movie 1).

Movie 4: Non-motion enhanced (“normal”) DIC movie corresponding to Movie 1.

Movie 5: Normal DIC movie corresponding to Movie 2.

Movie 6: Normal DIC movie corresponding to Movie 3.