Protein synthesis in axons and its possible functions.

Proteins synthesized in neuronal cell bodies are transported along axons by fast and slow axonal transport. Cytoskeletal proteins and cytosolic proteins that travel by slow axonal transport could take years to reach the terminals of meter-long axons, and it is difficult to see how proteins could last long enough to make this journey. How then are proteins supplied to the distal regions of long axons? Evidence has accumulated indicating that axons contain specific mRNAs and ribosomes and can synthesize cytoskeletal proteins and some other proteins. This review considers the direct evidence that proteins can be synthesized in axons and considers the possible functional significance of axonal protein synthesis. It remains unclear whether local protein synthesis could supply the cytoskeletal proteins and other slow-transported proteins required for the maintenance, plasticity, and regeneration of long axons.