Figure 1

The N-terminal domain of GMAP210 targets early compartments of the secretory pathway. (A) Confocal images of RPE1 cells transfected with the Nter-GFP construct (A1) and double labelled for GM130 (A2, merged image) and Golgin245 (A3, merged image). An enlarged view of A1 is shown at the bottom. Insets show enlarged views. In bottom panels, fluorescence intensity profiles of lines drawn in insets are shown. (B) Nter-GFP transfected RPE1 cells treated with nocodazole and stained for GM130 and Golgin245. Bottom panels show an enlarged view (left) and fluorescence intensity profiles (right) of the line drawn over a nocodazole-induced Golgi element. (C) Dynamics of the NterDsRed fusion protein in a RPE1 cell line stably expressing GT™-GFP. Selected frames at the indicated times from Movie 1 (in Additional file 1) are shown. An enlarged view is shown at the bottom. Arrows point to sites in which the NterDsRed protein is located between two membrane elements. (D) RPE1 cells treated with siRNA against GMAP210 for 72 h were transfected with the Nter-GFP construction (D1), incubated for 16 h and then fixed and immuno-stained for GM130 in red and GMAP210 in blue (D2). ND-NT indicates a non-depleted-non-transfected cell, D-NT a depleted non-transfected cell, and D-T a depleted and transfected cell. (E, F) Nter-GFP transfected cells (E) were treated with BFA (F) and then stained for Sec31 to reveal ER exit sites. Enlarged views of individual labellings are shown at right. Arrows indicate ERES containing the GMAP210 N-terminal domain. Bars = 5 μm