Establishing Neuronal Polarity with Environmental and Intrinsic Mechanisms.

Neurons are among the most morphologically complex cells. A distinction between two compartments, axon and dendrite, generates cellular domains that differ in membrane composition and cytoskeletal structure, and sets the platform on which morphogens, transcription programs, and synaptic activity sculpt neuronal form. The establishment of this distinction, called Neuronal Polarity, entails interpreting spatial and intrinsic cues and converting them to cytoskeletal rearrangements that give rise to axons and dendrites. Hence, this early developmental event underpins the future functional properties of the neuron to receive and transmit information. Here we review the current understanding of developmental cues and cell biological mechanisms that establish polarity in newborn neurons, synthesizing information from vertebrate and invertebrate model systems.