Fig. 4. Axonal targeting by the cytoplasmic axonal targeting signal in NgCAM requires the inactivation of the somatodendritic signal. (A) Lct27Nct45-114 (green) localizes preferentially to the axonal surface (arrows) of a transfected hippocampal neuron. DsRed was co-transfected to delineate all neuronal processes (red). Arrowheads indicate dendrites. (B) Diagrammatic depiction of LDLR-based NgCAM cytoplasmic tail chimeras. Chimeras contain either the proximal (amino acid residues 5-27) basolateral sorting signal of LDLR, which is co-linear with the endocytosis motif, or the distal (amino acid residues 28-50) basolateral signal of LDLR, which does not contain an endocytosis motif. Point mutations at Tyr35 and 37 inactivate the distal basolateral sorting signal. (C) The axon/dendrite polarity index was determined for the chimeras depicted in B. ^**P<0.001, ^***P<0.0001; statistically significant differences between bracketed constructs.