Pulse-chase transport assays in MDCK monolayers depleted of EXOC2, EXOC7, LEPROT, and PARD6B reveal three distinct phenotypes. FcRn-dependent IgG trafficking in monolayers depleted of the indicated genes (red) is compared with IgG trafficking in control monolayers transfected with nontargeting esiRNA (black). Transcytosis and recycling experiments were normalized to the 90-min time point of matched control monolayers transfected with nontargeting esiRNA, and internalization experiments were normalized to the matched nontargeting control. Each experiment was conducted in triplicate on two to four independent days; the number of replicates and days are indicated below each bar graph in the form of n = (replicates per experiment) × (number of independent experiments). Plots show the weighted mean ± SD across experiments (see Materials and methods). (A and B) Time course of basolaterally and apically directed IgG transcytosis as assessed by 60-min pulse and 90-min chase. (C and D) Time course of apical and basolateral IgG recycling as assessed by 60-min pulse and 90-min chase. For A–D, statistical significance was assessed for the 90-min time point by the Wilcoxon signed-rank test and adjusted for multiple hypothesis testing using Holm’s method. (E) Total cellular uptake of IgG after 60-min pulse. *, P < 0.05; as estimated by the Wilcoxon signed-rank test. **, P < 0.001; ***, P < 0.0001.