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Botulinum neurotoxins C, E and F bind gangliosides via a conserved binding site prior to stimulation-dependent uptake with botulinum neurotoxin F utilising the three isoforms of SV2 as second receptor.
- Source :
-
Journal of neurochemistry [J Neurochem] 2009 Sep; Vol. 110 (6), pp. 1942-54. Date of Electronic Publication: 2009 Jul 23. - Publication Year :
- 2009
-
Abstract
- The high toxicity of clostridial neurotoxins primarily results from their specific binding and uptake into neurons. At motor neurons, the seven botulinum neurotoxin serotypes A-G (BoNT/A-G) inhibit acetylcholine release, leading to flaccid paralysis, while tetanus neurotoxin blocks neurotransmitter release in inhibitory neurons, resulting in spastic paralysis. Uptake of BoNT/A, B, E and G requires a dual interaction with gangliosides and the synaptic vesicle (SV) proteins synaptotagmin or SV2, whereas little is known about the entry mechanisms of the remaining serotypes. Here, we demonstrate that BoNT/F as wells depends on the presence of gangliosides, by employing phrenic nerve hemidiaphragm preparations derived from mice expressing GM3, GM2, GM1 and GD1a or only GM3. Subsequent site-directed mutagenesis based on homology models identified the ganglioside binding site at a conserved location in BoNT/E and F. Using the mice phrenic nerve hemidiaphragm assay as a physiological model system, cross-competition of full-length neurotoxin binding by recombinant binding fragments, plus accelerated neurotoxin uptake upon increased electrical stimulation, indicate that BoNT/F employs SV2 as protein receptor, whereas BoNT/C and D utilise different SV receptor structures. The co-precipitation of SV2A, B and C from Triton-solubilised SVs by BoNT/F underlines this conclusion.
- Subjects :
- Animals
Binding Sites drug effects
Binding Sites genetics
Binding, Competitive drug effects
Binding, Competitive genetics
Botulinum Toxins pharmacology
Diaphragm drug effects
Diaphragm physiology
Dose-Response Relationship, Drug
Electric Stimulation methods
Gangliosides chemistry
Gangliosides deficiency
Isometric Contraction drug effects
Isometric Contraction physiology
Membrane Glycoproteins genetics
Mice
Mice, Inbred C57BL
Mice, Knockout
Models, Molecular
Mutagenesis, Site-Directed methods
Nerve Tissue Proteins genetics
Phrenic Nerve physiology
Protein Binding drug effects
Protein Binding physiology
Protein Isoforms genetics
Rats
Synaptic Vesicles metabolism
Botulinum Toxins metabolism
Gangliosides metabolism
Membrane Glycoproteins metabolism
Nerve Tissue Proteins metabolism
Protein Isoforms metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1471-4159
- Volume :
- 110
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- Journal of neurochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 19650874
- Full Text :
- https://doi.org/10.1111/j.1471-4159.2009.06298.x