Neuronal Receptors Display Cytoskeleton-Independent Directed Motion on the Plasma Membrane

Directed transport of transmembrane proteins is generally believed to occur via intracellular transport vesicles. However, using single-particle tracking in rat hippocampal neurons with a pH-sensitive quantum dot probe that specifically reports surface movement of receptors, we have identified a sub-population of neuronal EphB2 receptors that exhibit directed motion between synapses within the plasma membrane Itself. This receptor movement occurs independently of the cytoskeleton but is dependent on cholesterol and is regulated by neuronal activity.