Axoplasmic transport, also called axonal transport, is a cellular process responsible for movement of , lipids, synaptic vesicles, proteins, and other cell parts (i.e. organelles) to and from a neuron's cell body, through the cytoplasm of its axon (the axoplasm). Axons, which can be 1,000 or 10,000 times the length of the cell body, were originally thought not to contain any ribosomes as the means of producing proteins, and so were thought to rely on axoplasmic transport for all their protein needs. However, more recently, mRNA translation has been demonstrated in axons. Axonal transport is also responsible for moving molecules destined for degradation from the axon back to the cell body, where they are broken down by lysosomes.
Movement toward the cell body is called retrograde transport and movement toward the synapse is called anterograde transport.
The vast majority of axonal proteins are synthesized in the neuronal cell body and transported along axons. Axonal transport occurs throughout the life of a neuron and is essential to its growth and survival. Microtubules (made of tubulin) run along the length of the axon and provide the main cytoskeletal "tracks" for transportation. Kinesin and dynein are motor proteins that move cargoes in the anterograde (forwards from the soma to the axon tip) and retrograde (backwards to the soma (cell body)) directions, respectively. Motor proteins bind and transport several different cargoes including , cytoskeletal polymers, autophagosomes, and synaptic vesicles containing neurotransmitters.