Neuronal phosphoprotein that coats synaptic vesicles, binds to the cytoskeleton, and is believed to function in the regulation of neurotransmitter release. May play a role in noradrenaline secretion by sympathetic neurons (By similarity). Interacts with CAPON. Central and peripheral nervous systems. The A region binds phospholipids with a preference for negatively charged species. Phosphorylation at Ser-10 dissociates synapsins from synaptic vesicles. Phosphorylation at Ser-425 by MAPK1/ERK2 and/or MAPK3/ERK1 may play a role in noradrenaline secretion by sympathetic neurons (By similarity). Disease susceptibility may be associated with variants affecting the gene represented in this entry. Belongs to the synapsin family. There are several mRNAs and ESTs supporting this gene model. However, the genome sequence encoding the N-terminal part contains several sequence discrepancies. Several in-frame stop codons.