A neuronal phosphoprotein covers thesynaptic vesicles involved in the regulation of neurotransmitter releases and one of the most definite markers of synapses all through the central and peripheral nervous system.
Synapsin 1 gene is mapped on chromosome Xp11.23 that contains 13 exons with 706 amino acids encodes neuronal phosphoproteins which associate with the cytoplasmic surface of synaptic vesicles and distinguished by common protein domains. It is present in certain sensory nerve endings expressed in two splice variants that interacts with vesicle membranes as well as with actin and spectrin. It is made up of globular N-terminal and elongated C-terminal.
Synapsin 1 plays a critical role during axonogenesis,synaptogenesis, synaptic transmission and plasticity of mature neurons which suggest a potential role in various neuropsychiatric diseases. Its gene transcription is suppressed in non-neuronal tissues by the RE1-silencing transcription factors. It also serves as a substrate for different protein kinases and phosphorylation in the regulation of the nerve terminal.
Synapsin 1 genemutation is linked to significant neuropsychiatric disorders like autism and epilepsy. It is also associated with X-linked disorders with primary neuronal degeneration like Rett syndrome. It is revealed to be phosphorylated by calcium influx wherein depolarization of the presynaptic membrane stimulates calcium ion influx into the axonal nerve terminal of neurons and enhance the intracellular concentration of calcium ions.
Gene name: SYN1
Protein name: Synapsin-1