Stages 1 and 2. Co-expression of DMP1-eGFP (a) and the tonoplast marker TPK1-mRFP (b) shows in stage 1 colocalization at the vacuolar membrane (c) and occasional partial overlap at bulbs (d). Co-expression in stage 1 of DMP1-eGFP (e), YFP-HDEL labeling the ER lumen (f) and Man49-mCherry decorating Golgi vesicles (g) shows no localization of DMP1-eGFP in Golgi vesicles and no or only weak signals in the ER (h). Co-expression during stage 2 of DMP1-eGFP (i) and the ER membrane marker RFP-p24 (j) shows colocalization in the ER that exhibits cisternal morphology (k). Bulbs in tobacco epidermis cells visualized by electron microscopy (l). Scale bar, 20 μm except D, 2 μm.