Platyhelminth voltage-gated calcium channel complex (VGCC)

The Platyhelminth voltage-gated calcium channel (VGCC) complex is a critical membrane protein assembly found in parasitic flatworms, including schistosomes and tapeworms (PubMed: 11562363). It typically consists of a pore-forming alpha-1 subunit and auxiliary subunits, such as the beta and alpha-2-delta subunits, which regulate the channel's gating properties and expression (PubMed: 16707413). In platyhelminths, these channels are essential for mediating the calcium influx required for muscle contraction, locomotion, and the maintenance of the tegument, the parasite's protective outer layer (PubMed: 24453457). The complex is the primary molecular target of praziquantel, the gold-standard anthelmintic drug used globally to treat schistosomiasis and other trematode or cestode infections (PubMed: 31036786). Binding of the drug to the VGCC complex, particularly the unique beta subunit, causes a massive entry of calcium into the parasite's cells. This results in rapid paralysis and tegumental damage, which exposes parasite antigens to the host's immune system and ultimately leads to the death of the worm (PubMed: 15939498).

Other names

Schistosome voltage-gated calcium channelFlatworm VGCCCaV channelPraziquantel targetVoltage-dependent calcium channel

Praziquantel acts as an allosteric modulator of the voltage-gated calcium channel complex, specifically interacting with the variant beta subunit (Sm.CaVβ) to induce a rapid and sustained influx of calcium ions (PubMed: 31036786). This influx triggers immediate tetanic muscle contraction and causes severe vacuolization and disintegration of the parasite tegument (PubMed: 15939498).