Fig. 1. Expression of GFP-tagged ER marker proteins was induced in a pattern similar to that of the endogenous ER proteins in the dendrites. (A-C) Dense reticular structures and spotty patterns of the GFP-tagged ER markers in living neurons: (A) GFP-KDEL, (B) GFP-SERCA2a, and (C) GFP-Ins(1,4,5)P₃R1, which are quite similar to those of endogenous ER proteins (D,E). Untransfected neurons were fixed, permeabilized and stained with anti-Ins(1,4,5)P₃R1 monoclonal antibody 18A10 (D) or anti-calnexin polyclonal antibody (E). All the images were taken with a confocal microscope. Arrowheads indicate spotty shapes. Scale bar: 10 µm.