Files in this Data Supplement:

• Web Movie 1. (QuickTime Movie, 7,447 KB) - FcRn-GFP transfected HMEC-1 cells were imaged at 37°C in phenol red free HAM'S medium. The movement of FcRn-GFP was tracked with a fast image acquisition rate of 100 ms/frame. Images were acquired and processed as described in the Methods (single color configuration). This movie is a 15 s section (65-80 s, 151 frames) of a 100 s image series. Data show representative cells from at least 6 independent observations. Note that a large tubule/vesicle merges with a sorting endosome (refer to arrowheads on Fig. 2a).
• Web Movie 2. (QuickTime Movie, 669 KB) - FcRn-GFP transfected HMEC-cells were pulsed for 60 minutes with 1 mg/ml Alexa 546 labeled human IgG1 and then washed. Live cell imaging was carried out immediately following the washes. Images were acquired and processed as described in the Methods (dual-band emission filter configuration). This movie is a 20.4 s section (8.4-28.8 s, 18 overlays) of a 360 s image series. Data show representative cells from at least 34 independent experiments. Note that a FcRn-GFP (green), and IgG1 (red) positive tubule leaves a sorting endosome (refer to arrowheads on Fig. 4c).
• Web Movie 3. (QuickTime Movie, 708 KB) - FcRn-GFP transfected HMEC-1 cells were pulsed for 60 minutes with 1 mg/ml Alexa 546 labeled H435A and then washed. Live cell imagine was carried out immediately following the washes. Images were acquired and processed as described in the Methods (dual-band emission filter configuration). This movie is a 66 s section (54-120 s, 56 overlays of a 600 s image series. Data show representative cells from at least 18 independent experiments. Note that a FcRn-GFP (green) positive tubule leaves a H435A (red) positive sorting endosome (refer to arrowheads on Fig. 5a).