The role of endosomal-recycling in long-term potentiation.

Long-term potentiation (LTP) defines persistent increases in neurotransmission strength at synapses that are triggered by specific patterns of neuronal activity. LTP, the most widely accepted molecular model for learning, is best characterised at glutamatergic synapses on dendritic spines. In this context, LTP involves increases in dendritic spine size and the insertion of glutamate receptors into the post-synaptic spine membrane, which together boost post-synaptic responsiveness to neurotransmitters. In dendrites, the material required for LTP is sourced from an organelle termed the endosomal-recycling compartment (ERC), which is localised to the base of dendritic spines. When LTP is induced, material derived from the recycling compartment, which contains α-amino-3-hydroxy-5-methyl-4-isoxazole propionate-type glutamate receptors (AMPARs), is mobilised into dendritic spines feeding the increased need for receptors and membrane at the spine neck and head. In this review, we discuss the importance of endosomal-recycling and the role of key proteins which control these processes in the context of LTP.