F-actin and PIP3 localization at the IS. OT-1 CTLs expressing RFP-labeled Lifeact together with GFP-labeled Grp1PH were analyzed by TIRF microscopy (60× magnification) on lipid bilayers containing pMHC and ICAM-1. A 15× time-lapse video is shown, with time displayed (minutes:seconds) in the top left corner. Bars, 5 µm. The video is representative of at least 80 cells imaged over four independent experiments.
