Movie 2

Rap1 is required for the centralization of antigen-bound BCRs into a cSMAC. Primary B cells from MD4 mice, which express a transgenic BCR specific for HEL, were transduced with control siRNA or Rap1a/b siRNA. These cells were stained with Cell Trace Far Red (blue) and added to adherent Cos-7 cells expressing HEL-GFP (green). Timelapse spinning disk confocal microscopy was used to acquire images every 12 s starting at 1 min after adding B cells to the APCs and continuing until t = 12 min. The video is played back at 10 frames per second (120X real time).

The Rap1–cofilin-1 pathway coordinates actin reorganization and MTOC polarization at the B cell immune synapse

Jia C. Wang, Jeff Y.-J. Lee, Sonja Christian, May Dang-Lawson, Caitlin Pritchard, Spencer A. Freeman, and Michael R. Gold

J Cell Sci 2017. 130:1094-1109; doi: 10.1242/jcs.191858