Synaptic vesicle glycoprotein 2A and polysialogangliosides (SV2A and polysialogangliosides)

Synaptic vesicle glycoprotein 2A (SV2A) and polysialogangliosides (such as GT1b and GD1a) constitute the dual-receptor complex essential for the entry of Botulinum neurotoxin type A (BoNT/A) into cholinergic nerve terminals. SV2A is an integral membrane protein found in synaptic vesicles across the central and peripheral nervous systems, where it plays a critical role in regulating calcium-dependent exocytosis and neurotransmitter release (Source: UniProt Q7L0J3; PubMed: 16469928). Polysialogangliosides are sialic acid-containing glycosphingolipids that act as initial low-affinity anchors on the presynaptic membrane, facilitating the subsequent high-affinity interaction with the luminal loop of SV2A as vesicles fuse and recycle (Source: PubMed: 16543454). This interaction is the primary pathway for the internalization of therapeutic botulinum toxins used to treat conditions like chronic migraine, focal dystonias, and spasticity by preventing the release of acetylcholine. Additionally, SV2A is a known target for antiepileptic drugs like levetiracetam, which modulate synaptic transmission to reduce seizure activity (Source: PubMed: 15254512).

Other names

SV2A-ganglioside receptor complexBotulinum neurotoxin type A receptor complexSynaptic vesicle protein 2AGT1b/GD1a gangliosides

Botulinum neurotoxin type A (BoNT/A) utilizes a double-receptor mechanism where it first binds to polysialogangliosides on the neuronal surface to concentrate the toxin, followed by high-affinity binding to the luminal domain of SV2A during synaptic vesicle recycling, facilitating its endocytosis into the neuron.