An evolutionarily conserved dileucine motif in Shal K+ channels mediates dendritic targeting.

The molecular mechanisms underlying polarized sorting of proteins in neurons are poorly understood. Here we report the identification of a 16 amino-acid, dileucine-containing motif that mediates dendritic targeting in a variety of neuronal cell types in slices of rat brain. This motif is present in the carboxy (C) termini of Shal-family K+ channels and is highly conserved from C. elegans to humans. It is necessary for dendritic targeting of potassium channel Kv4.2 and is sufficient to target the axonally localized channels Kv1.3 and Kv1.4 to the dendrites. It can also mediate dendritic targeting of a non-channel protein, CD8.