Latrotoxins (LaTXs) are presynaptic pore-forming neurotoxins found in the venom of Latrodectus spiders. The venom contains a toxic cocktail of seven LaTXs, with one of them targeting vertebrates (α-latrotoxin (α-LTX)), five specialized on insects (α, β, γ, δ, ε- latroinsectotoxins (LITs), and one on crustaceans (α-latrocrustatoxin (α-LCT)). LaTXs bind to specific receptors on the surface of neuronal cells, inducing the release of neurotransmitters either by directly stimulating exocytosis or by forming Ca 2+ -conductive tetrameric pores in the membrane. The pores formed by α-LTX in the membrane are permeable to Ca2+ and therefore allow an influx of Ca2+ into the cell. This influx into an excitable cell stimulates exocytosis directly and efficiently. The cation influx is proportional to the amount of pores and hence the amount of involved receptors expressed on the cell membrane. Also Ca2+ strongly facilitates the forming of the tetramers and so its pore formation. The pore is also permeable to neurotransmitters, which causes massive leakage of the neurotransmitter pool in the cytosol. Here you can see a recent cryoEM structure of the Delta-latroinsectotoxin in a dimeric form (PDB code: 7PTY)
#molecularart ... #immolecular ... #toxin ... #spider ... #calcium ... #membrane ... #dimer ... #cryoem
Toxin structure rendered with @proteinimaging and finished with @corelphotopaint
#molecularart ... #immolecular ... #toxin ... #spider ... #calcium ... #membrane ... #dimer ... #cryoem
Toxin structure rendered with @proteinimaging and finished with @corelphotopaint
