Vesicular Sorting to Axons and Dendrites

Abstract

Neuronal polarity underlies vectorial electrical signaling by vertebrate neurons. To ensure the proper conduction of electrical signals, channels and receptors have to be distributed to the correct locations. Equalizing the distribution of channels and receptors to uniformity on the membrane would affect the excitability and firing properties of the neuron and lead to dysfunctional and/or nonfunctional circuits. Neuronal function therefore relies on successfully compartmentalizing the neuronal plasma membrane and creating a multitude of molecularly distinct subdomains. At the most basic, one can distinguish proteins enriched on the axon from proteins enriched on the soma and dendrites, the somatodendritic domain. Furthermore, many proteins are found enriched in subdomains of the somatodendritic or axonal domains, such as synapses, distal or proximal dendrites, soma, axon initial segments, and nodes of Ranvier. Several mechanisms are discussed which contribute to the nonhomogeneous distribution of receptors and channels in the membrane.