Protein sorting in the synaptic vesicle life cycle

Dario Bonanomi, Fabio Benfenati, Flavia Valtorta

Research output: Contribution to journalArticlepeer-review


At early stages of differentiation neurons already contain many of the components necessary for synaptic transmission. However, in order to establish fully functional synapses, both the pre- and postsynaptic partners must undergo a process of maturation. At the presynaptic level, synaptic vesicles (SVs) must acquire the highly specialized complement of proteins, which make them competent for efficient neurotransmitter release. Although several of these proteins have been characterized and linked to precise functions in the regulation of the SV life cycle, a systematic and unifying view of the mechanisms underlying selective protein sorting during SV biogenesis remains elusive. Since SV components do not share common sorting motifs, their targeting to SVs likely relies on a complex network of protein-protein and protein-lipid interactions, as well as on post-translational modifications. Pleiomorphic carriers containing SV proteins travel and recycle along the axon in developing neurons. Nevertheless, SV components appear to eventually undertake separate trafficking routes including recycling through the neuronal endomembrane system and the plasmalemma. Importantly, SV biogenesis does not appear to be limited to a precise stage during neuronal differentiation, but it rather continues throughout the entire neuronal lifespan and within synapses. At nerve terminals, remodeling of the SV membrane results from the use of alternative exocytotic pathways and possible passage through as yet poorly characterized vacuolar/endosomal compartments. As a result of both processes, SVs with heterogeneous molecular make-up, and hence displaying variable competence for exocytosis, may be generated and coexist within the same nerve terminal.

Original languageEnglish
Pages (from-to)177-217
Number of pages41
JournalProgress in Neurobiology
Issue number4
Publication statusPublished - Nov 2006


  • Adaptor protein complexes
  • Exo-endocytosis
  • Membrane traffic
  • Neurotransmission
  • PC12 cells
  • Phosphorylation
  • Secretory pathway
  • Synaptic vesicle pools
  • Synaptic-like microvesicles

ASJC Scopus subject areas

  • Neuroscience(all)


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