VAMP7 and TYRP1 traffic to melanosomes in BLOC-1–dependent membrane tubules. (a–f) WT melan-Ink4a cells transiently transfected with mCh-STX13 (red) and either TYRP1-GFP (green, a–c; cell shown in Fig. S2 a) or GFP-VAMP7 (green; d-f; cell shown in Figs. 5 d and S2 b) were analyzed 24 h later by spinning-disk confocal microscopy at 1 fps. Regions from a single frame are shown. Arrows, mCh-STX13-labeled endosomal tubules; arrowheads, TYRP1-GFP-labeled melanosome (a–c) or GFP-VAMP7-labeled tubule (d-f). Note that tubular mCh-STX13–labeled endosomes in live-cell analyses appear punctate upon fixation (e.g., Fig. 2, g, s, and t). Bar, 1 µm. (g–n) melan-pa melanocytes were transiently transfected with myc-Pallidin, mCh-STX13 and either GFP-VAMP7 (g–j) or TYRP1-GFP (k-n) and analyzed 20 h later by spinning-disk confocal microscopy at ∼1 fps. (g and k) Single frames of representative cells showing overlap of mCh-STX13 with GFP-VAMP7 (g) or TYRP1-GFP (k). Bars, 10 µm. Image sequences from the boxed regions in g and k are magnified five times in h–j and l–n, respectively. Arrows show mCh-STX13–labeled tubules containing GFP-VAMP7 (h–j) or TYRP1-GFP (l–n). Elapsed time (in seconds) is indicated at the lower right. Bars, 1 µm.