Differentiated CAD cells express and transport APP. (A to C) Neuronal phenotype of differentiated CAD cells. (A) CAD cells cultured in the presence of serum. Note that upon serum withdrawal, CAD cells extend long processes (B). (C) Processes at high magnification. (D to G) APP is localized to cell bodies and processes of CAD cells, as detected with antibodies to carboxy-terminal (APPC) (D), amino-terminal (APPN) (E), and Aβ (4G8 [F] and anti-rodent Aβ [rodAβ] [G]) regions of APP. Note that no particular accumulation of anti-Aβ immunoreactive material at neurite terminals is seen (F and G). (H) Diagram of APP695 showing the polypeptides generated by secretase cleavage in the two main APP processing pathways. The positions of epitopes detected by antibodies used in this study are shown (a to d). The vertical lines indicate the transmembrane domain of APP. Bars = 50 μm (A and B), 10 μm (C), and 20 μm (D to G).