Intracellular transport of synaptic proteins

Abstract

Intracellular transport delivers cellular cargoes to and from their sites of action. Neurons are characterized by a polar and excitable nature and require the precise delivery of mRNAs, proteins and organelles to specific subcellular domains. Multiple motor-protein complexes have been identified that actively transport synaptic cargoes along microtubules and actin filaments in both anterograde and retrograde directions. Different synaptic proteins couple via adaptor molecules to molecular motors and individual cargo adaptors also mediate scaffolding functions at postsynaptic membrane specializations or have been found to participate to the navigation of cargoes to either axons or dendrites. Increasing evidence suggests for a functional crosstalk between synaptic activation and the intracellular transport machinery. Whether microtubule-based transport contributes to long-term strengthening or weakening of synapses is currently under investigation. A variety of posttranslational modifications of tubulin positively or negatively influence cargo traffic and are suggested to act as molecular traffic signs in transport regulation.