Fig. 2. Mutant Ykt6p longin domains are targeted normally. Mutations were introduced into N-terminally Myc-tagged yeast Ykt6p longin domain (residues 1-139) and transfected into PC12 cells. See Table 1 for the complete listing of mutations. Subcellular localization of each mutant and endogenous rat ykt6 was examined by double-labeling fluorescent microscopy using anti-Myc antibody (9E10) and anti-rat-Ykt6 antibody. Whereas colocalization of mutants with endogenous rat Ykt6 is shown for R2E/V8N, F39E and I59EA (top three rows; 12%, 18% and 16% overlap, respectively), only the subcellular localization of Myc-tagged mutant proteins is shown for E100K/Y101N, R50E/R56E and F42 (bottom row). Arrows point to a subset of overlapping punctate structures. Scale bar, 10 µm.