FIG. 4.

U24 blocks CD3ɛ access to Rab11 recycling endosomes. Cells expressing GFP-Rab proteins and either U24/EGFP (right panels) or EGFP alone (left panels) were sorted for high GFP expression that corresponded to low surface CD3 expression. These cells were then fixed, permeabilized, and stained with an anti-CD3ɛ antibody (OKT3) and a rhodamine-conjugated secondary antibody. Cells were visualized using a Zeiss 510 META/NLO confocal microscope with a 63× objective, and images were magnified six times. Rab5 and Rab4 are markers of early and sorting endosomes, respectively. Rab9 is a marker of late endosomes, and Rab11 is a marker of recycling endosomes. Yellow arrows indicate areas of colocalization, while white arrows indicate areas of noncolocalization.