https://doi.org/10.5061/dryad.6djh9w16v

In these experiments, microtubules were grown with a yeast-kinetochore-decorated bead attached to the microtubule's plus end. Using an optical trap, we applied constant forces ranging from 0.5 to 17 pN to the plus end via the bead and recorded the microtubule's growth and/or shortening, as well as the stochastic switching between these two states. A switch from growth to shortening is termed a 'catastrophe,' while a switch from shortening to growth is termed a 'rescue.'

Force-clamp viewer.pxp displays microtubule plus end position vs time and is labeled with the corresponding force under which that microtubule was grown. Growth speed vs time data is also displayed using a 2-second running velocity, as is analysis of pausing behaviors (when microtubules stochastically stop growing during periods of net growth) based on this running velocity.

Code/Software

To run the force-clamp viewer, install the free trial of Igor Pro 9 at https://www.wavemetrics.com/software/igor-pro-9, download Force-clamp_viewer.zip, and extract all files to access Force-clamp_viewer.pxp.

When you load this file, a front panel will appear and allow you to click through recordings within a given force range with the 'Next Trace' and 'Previous Trace' buttons. Click the checkbox next to 'Mark pauses?' to highlight pauses in purple, but please note that graphs take longer to generate when this option is selected.

Force-clamp_viewer_091323.txt (available at https://doi.org/10.5281/zenodo.8433062) is an external copy of the software used to run the force-clamp viewer, but is not necessary to download to run Force-clamp_viewer.pxp.

Data available without the use of Igor Pro 9

Additionally, each recording is saved in a separate .csv file. Each .csv file contains 4 columns, the contents of which are listed below:

1. Tip position of the microtubule (in nm)
2. Smoothed force on the microtubule (in pN)
3. 'Raw' force on the microtubule (in pN)
4. Time (in s)

Force-clamp example document.dox contains an example recording and summary statistics so that users can ensure that they are downloading and interpreting these files correctly.

Finally, in Force clamp metadata.csv, each row contains the following information about a given recording:

1. File name
2. Average force (in pN)
3. Standard deviation of force (in pN)
4. Duration of the assembly period, if present (in s)
5. Growth speed during the assembly period, if present (in nm/s)
6. Duration of the pre-catastrophe pause period, if present (in s)
7. Growth speed during the pre-catastrophe pause period, if present (in nm/s)
8. Duration of the shortening period, if present (in s)
9. Shortening speed during the shortening period, if present (in nm/s)
10. How the event ended (detach, rescue, interrupted, or other)