Figure 2. LAPTM4b recruits the Leu transporter to lysosomes.

(a,b) Recruitment of LAT1 to lysosomes by LAPTM4b. HeLa cells were transfected with mCherry (mCh) LAT1 (red) alone or with HA-LAPTM4b. Cells were fixed 24 h post transfection and stained for the nucleus (4,6-diamidino-2-phenylindole (DAPI), cyan), lysosomes (LAMP1, green), plasma membrane (PM, concanavalinA, blue) and LAPTM4b (anti-HA, blue). Scale bar, 15 μm. (c) Quantification of co-localization of LAPTM4b with LAT1 or 4F2hc (Pearson's coefficient). The immunofluorecence imaging for 4F2hc is shown in Supplementary Fig. 2a,b. In addition to its presence in lysosomes, LAPTM4b was also detected at the plasma membrane in 54 and 49% of cells co-expressing LAPTM4b with LAT1 or 4F2hc, respectively. P value was calculated by the Student's t-test. Scale bars, 15 μm.