A) Cartoon schematics showing the GFPnb targeting protein binding to soluble eGFP. Here the ligand, GFPnb, is a nanobody against GFP. B) Confocal images of CHO wild type cells transiently expressing the GFPnb targeting protein. The single bright cell in the mRFP fluorescent channel is the only cell in this field of view that expresses the GFPnb targeting protein (compare brightfield and mRFP fluorescent images). As expected, only this cell recruits soluble eGFP from solution, demonstrating specific binding. C) Confocal images of a GPMV derived from CHO cells stably expressing the GFPnb targeting protein (red). Incubation of GPMVs with soluble eGFP shows binding. D) Display of the GFPnb targeting protein is correlated with recruitment of soluble eGFP based on fluorescence intensity analysis. A total of 39 GPMVs were analyzed, using two measurements per GPMV on opposite edges. All scale bars, 10 µm.