Fig. 3. Exogenously expressed hKCNQ2-cmyc and hKCNQ3-FLAG are primarily localized intracellulary in primary hippocampal neurons. Hippocampal neurons expressing hKCNQ2-cmyc (hQ2-myc) or hKCNQ3-FLAG (hQ3). Transfected neurons were fixed and double-labeled with anti-cmyc or anti-hKCNQ3 together with anti-ankyrin-G (AnkG) (A), anti-MAP2 (B) or anti-protein disulfide isomerase (PDI) (C) antibodies. Neither hKCNQ2-cmyc nor hKCNQ3-FLAG displayed a selective enrichment at the AIS (A) and no accumulation of the channel subunits in MAP-2 negative compartments was observed (B). Instead, both subunits displayed a primarily intracellular localization that partly co-localized with the endoplasmic reticulum marker PDI (C). White boxes in the merged images in C represent the magnified regions displayed below. Arrows mark the position of the AIS, while arrowheads point to the distal axon. Bar, 20 µm.