Hook1 and Rab22a regulate the sorting of CIE cargo proteins into the recycling tubular compartment. (A) HeLa cells expressing GFP-Rab22a S19N alone or coexpressing GFP-Rab22a S19N and HA-Hook1 were allowed to internalize anti-CD147 antibodies for 30 min at 37°C. HA-Hook1 was visualized using rabbit anti-HA and Alexa Fluor 594–conjugated anti–rabbit antibodies. Bars, 10 µm. (B) Quantitative analysis of the percentage of GFP-Rab22a S19N cells exhibiting tubular endosomes loaded with CD147 in the absence or presence of HA-Hook1. Data presented in the graph are the mean of three independent experiments ± SD (error bars).