Synaptic vesicle protein 2 and neuronal gangliosides (SV2/Ganglioside complex)

Synaptic vesicle protein 2 (SV2) and neuronal gangliosides function as a high-affinity dual-receptor complex for Botulinum neurotoxins (BoNTs). SV2 is a transmembrane glycoprotein with three isoforms (SV2A, SV2B, and SV2C) that is essential for calcium-regulated neurotransmitter release (UniProt Q7L0J3). Neuronal gangliosides, such as GT1b and GD1a, are sialic acid-containing glycosphingolipids that act as initial docking sites, concentrating the toxin on the neuronal membrane (Rummel, 2016). The binding of BoNT/A to the luminal domain of SV2 occurs during vesicle exocytosis, facilitating toxin internalization via endocytosis (Dong et al., 2006). Once internalized, the toxin cleaves SNARE proteins like SNAP-25, inhibiting acetylcholine release and causing paralysis. Additionally, SV2A is the specific molecular target for antiepileptic drugs like levetiracetam and brivaracetam, which modulate synaptic vesicle trafficking to reduce neuronal excitability (Lynch et al., 2004). This dual-receptor system is therefore central to both the pathogenesis of botulism and the therapeutic action of major neuromuscular and antiepileptic medications.

Other names

SV2ASV2BSV2CGT1bGD1aGD1bBotulinum neurotoxin receptor complexSynaptic vesicle glycoprotein 2

Botulinum neurotoxins utilize gangliosides for initial membrane docking and SV2 for high-affinity binding and internalization, leading to SNARE protein cleavage and inhibition of acetylcholine release. Antiepileptic drugs like levetiracetam bind to SV2A to modulate synaptic vesicle exocytosis and reduce hypersynchronous neuronal firing.