Fig. 2. In vivo overexpressed furin is localized to the Golgi and the cell surface. 24 hours after the injection of plasmids pCDNA3/RSV/Furin (Fur) (A,C) and pCDNA3/RSV/Furin-HA (Fur-HA) (B,D,E) into the tail vein of mice, kidneys were prepared for immunocytochemistry. (A) Furin immunofluorescence on cryosection is found over most of the glomerular cells. (B) Cryosection of kidney transduced with the HA-tagged furin and labeled with the anti-HA antibody; the immunofluorescence is restricted to those cells expressing the exogenous furin-HA. (A,B) The labeling is found in the perinuclear region (asterisks), in vesicular structures and on plasma membranes (arrows). (C-E) Immunogold on furin- and furin-HA-transduced cells. The many gold particles revealing furin (C) and furin-HA (D) are located at the cell surface of podocytes (P) and endothelial cells (End). Labeling is preferentially associated with the slit diaphragms (arrowheads) and endothelial fenestrations (arrows). (E) Golgi apparatus within the cell body of a podocyte transduced with furin-HA. The gold particles are found concentrated on one side of the Golgi, most probably the TGN. (A,B) Bars, 5 µm. (C-E) Bars, 200 nm.