The function of Ensembl gene identifier ENSG00000008056 (SYN1, synapsin I) is as follows. Neuronal phosphoprotein that coats synaptic vesicles, and binds to the cytoskeleton. Acts as a regulator of synaptic vesicles trafficking, involved in the control of neurotransmitter release at the pre-synaptic terminal (PubMed:21441247, PubMed:23406870). Also involved in the regulation of axon outgrowth and synaptogenesis (By similarity). The complex formed with NOS1 and CAPON proteins is necessary for specific nitric-oxid functions at a presynaptic level (By similarity). {ECO:0000250|UniProtKB:O88935, ECO:0000250|UniProtKB:P09951, ECO:0000269|PubMed:21441247, ECO:0000269|PubMed:23406870}.