Expression of non-secretory reporters to analyze the endocytic pathway. A-C: schematic representation of the constructs Box-GFP (A), Box-GFP-Ub (B) and GFP-Ub (C). D-F: tobacco mesophyll protoplasts were transfected with the corresponding plasmids as indicated below. (D) Box-GFP is efficiently recruited onto the PM, while Box-GFP-Ub (E) predominantly localizes to punctae. F: GFP-Ub is homogenously distributed throughout the cytoplasm and the nuclear matrix. G-I: Localization of the reporters given above in planta, confirming the results from (D-E). I: 3D projection of a leaf epidermal cell expressing Box-GFP-Ub. Scale bars = 5 μm.