Colocalization of βAPP with F3 and G_αo in neurons in vitro. Cells cultured for 5 d in vitro were fixed with paraformaldehyde and double-stained for βAPP (22C11) and F3 (A,A′) or NCAM (B,B′), or G_αo (C–E). The confocal section with the highest pseudocolor intensity is presented for each double-labeling. Double detections (CY3 for βAPP and FITC for F3, NCAM, or G_αo) are shown at low (A,B, C) and high (A′,B′, C′, D,E) magnification. The low magnification illustrates that only limited areas of the axons are labeled (except for NCAM). The high magnification demonstrates a colocalization of βAPP with either F3 (A′) or G_αo (C′,D, E). In E, the strong staining corresponds to an axon in close apposition with a faintly βAPP-positive cell body. Scale bars:A, B, C, 20 μm; A′, B′, C′,D, E, 10 μm.