title: Association of botulinum neurotoxin serotypes a and B with synaptic vesicle protein complexes.
abstract: Botulinum neurotoxins (BoNTs) elicit flaccid paralysis through cleavage of SNARE proteins within peripheral neurons. There are seven serotypes of the BoNTs, termed A-G, which differ in the SNARE protein and/or site that is cleaved. BoNTs are single-chain toxins that comprise an N-terminal zinc metalloprotease domain that is disulfide linked to the C-terminal translocation/receptor binding domain. SV2 and synaptotagmin have been identified as receptors for BoNT serotypes A and B, respectively. Using affinity chromatography, BoNTs A and B were observed to bind synaptic vesicle protein complexes in synaptosome lysates. Tandem LC-MS/MS identified SV2, synaptotagmin I, synaptophysin, vesicle-associated membrane protein 2 (VAMP2), and the vacuolar proton pump as components of the BoNT-receptor complex. Density gradient analysis showed that BoNT serotypes A and B exhibited unique interactions with the synaptic vesicle protein complexes. The association of BoNT serotypes A and B with synaptic vesicle protein complexes implicates a physiological role for protein complexes in synaptic vesicle biology and provides insight into the interactions of BoNT and neuronal receptors.
authors.affiliation: Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Baldwin
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Barbieri
mesh_terms: D000818:Animals; D001905:Botulinum Toxins / Q000378:metabolism*; D019274:Botulinum Toxins, Type A / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D051381:Rats; D013572:Synaptic Vesicles / Q000378:metabolism*; D016708:Synaptophysin / Q000378:metabolism; D050863:Synaptotagmin I / Q000378:metabolism; D050861:Synaptotagmin II / Q000378:metabolism; D050988:Vesicle-Associated Membrane Protein 2 / Q000378:metabolism
chemical_list: D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; C489618:Sv2a protein, rat; D016708:Synaptophysin; D050863:Synaptotagmin I; D050861:Synaptotagmin II; C494264:Syt2 protein, rat; D050988:Vesicle-Associated Membrane Protein 2; C096323:rimabotulinumtoxinB; D001905:Botulinum Toxins; D019274:Botulinum Toxins, Type A