Neuronal protein that plays several roles in synaptic activity such as regulation of synaptic vesicle trafficking and subsequent neurotransmitter release ( , ). Participates as a monomer in synaptic vesicle exocytosis by enhancing vesicle priming, fusion and dilation of exocytotic fusion pores (, ). Mechanistically, acts by increasing local Ca(2+) release from microdomains which is essential for the enhancement of ATP-induced exocytosis . Acts also as a molecular chaperone in its multimeric membrane-bound state, assisting in the folding of synaptic fusion components called SNAREs (Soluble NSF Attachment Protein REceptors) at presynaptic plasma membrane in conjunction with cysteine string protein-alpha/DNAJC5 . This chaperone activity is important to sustain normal SNARE-complex assembly during aging . Also plays a role in the regulation of the dopamine neurotransmission by associating with the dopamine transporter (DAT1) and thereby modulating its activity .
Subcellular locations: Cytoplasm, Membrane, Nucleus, Synapse, Secreted, Cell projection, Axon
Membrane-bound in dopaminergic neurons . Expressed and colocalized with SEPTIN4 in dopaminergic axon terminals, especially at the varicosities (By similarity).
Highly expressed in presynaptic terminals in the central nervous system. Expressed principally in brain.