Isoform IB of Synapsin-1

Synapsin-1 isoform IB is a neuron-specific phosphoprotein encoded by SYN1 that regulates synaptic vesicle dynamics and neurotransmitter release. This presynaptic protein is a key component of the synaptic vesicle cycle and plays critical roles in synaptic plasticity and short-term synaptic facilitation (UniProt: P17600-2).

Synapsin-1 is abundantly expressed in the brain and concentrated at synapses, where it modulates vesicle mobilization and docking. The protein is essential for normal synaptic transmission and has been implicated in various neurological conditions affecting cognition and memory.

This isoform shows altered abundance in Alzheimer's disease: it is upregulated in post-mortem AD brain tissue compared to age-matched controls (mean log2 fold-change +0.60, Chaparral AD proteomics). This upregulation was detected across subcellular fractions from human brain samples, suggesting a potential compensatory response or pathological accumulation in AD neurodegeneration.