Abstract:

Many different types of polarized eukaryotic cells have been shown to segregatesynthesis for some protein subpopulations to cytoplasmic domains distant from their nucleus. For neurons, these distances can be tens-to-thousands fold more than the diameter of the cell body. Both axons and dendrites make use of this localized protein synthesis to bring autonomy to these far reaches of the cytoplasm. Oftentimes this local mRNA translation is used to mount a rapid response to extracellular stimuli encountered by the distal axon and dendrite. Indeed, activating translation of mRNAs residing locally at the synapse or growth cone brings a much more rapid response than could be achieved by transporting new proteins from the cell body. The neuron likely reapsa cost benefit from this mechanism in terms of energy consumption, since multiple protein copies can be generated from a single mRNA through sequential rounds of translation. Localized protein synthesis could also more effectively positiona protein near its site of action or even bring an unanticipated novel function to the protein.