GCCSs are dynamic and, at moderate CD8/LDLR levels, generate nonterminal endocytic events. BSC1 cells were cultured as described in Fig. 1 and observed by dual-color TIRF-FM (A, Bb, C), electron microscopy (Ba), or spinning disk confocal microscopy (D). (A) Montage shows lifetime of a CCP. Arrowhead indicates nonterminal event. (B) In the presence of mild CD8/LDLR expression, CCPs tend to cluster and undergo nonterminal endocytic events. (C) GCCSs are dynamic and change morphology. (D) A small area in GCCSs has been bleached (indicated by square) and FRAP was recorded and quantified. Bars: (A) 400 nm; (Ba) 200 nm; (Bb) 600 nm; (C and D) 2 µm.