F-actin transiently accumulated at TCR-MCs in the initial phase of activation. TIRF videos of TCR (H57)–Dy549 and Lifeact-GFP in T cells placed on 1 µM Ag–loaded planer bilayer were taken at the rate of one frame per 5 s for 5 min. In the merged images, green and red show Lifeact-GFP and TCRs, respectively. The fields of 18-µm squares for each color or merged videos are arranged.
