title: Widespread sequence variations in VAMP1 across vertebrates suggest a potential selective pressure from botulinum neurotoxins.
abstract: Botulinum neurotoxins (BoNT/A-G), the most potent toxins known, act by cleaving three SNARE proteins required for synaptic vesicle exocytosis. Previous studies on BoNTs have generally utilized the major SNARE homologues expressed in brain (VAMP2, syntaxin 1, and SNAP-25). However, BoNTs target peripheral motor neurons and cause death by paralyzing respiratory muscles such as the diaphragm. Here we report that VAMP1, but not VAMP2, is the SNARE homologue predominantly expressed in adult rodent diaphragm motor nerve terminals and in differentiated human motor neurons. In contrast to the highly conserved VAMP2, BoNT-resistant variations in VAMP1 are widespread across vertebrates. In particular, we identified a polymorphism at position 48 of VAMP1 in rats, which renders VAMP1 either resistant (I48) or sensitive (M48) to BoNT/D. Taking advantage of this finding, we showed that rat diaphragms with I48 in VAMP1 are insensitive to BoNT/D compared to rat diaphragms with M48 in VAMP1. This unique intra-species comparison establishes VAMP1 as a physiological toxin target in diaphragm motor nerve terminals, and demonstrates that the resistance of VAMP1 to BoNTs can underlie the insensitivity of a species to members of BoNTs. Consistently, human VAMP1 contains I48, which may explain why humans are insensitive to BoNT/D. Finally, we report that residue 48 of VAMP1 varies frequently between M and I across seventeen closely related primate species, suggesting a potential selective pressure from members of BoNTs for resistance in vertebrates.
authors.affiliation: Department of Microbiology and Immunobiology, Harvard Medical School and Division of Neuroscience, New England Primate Research Center, Southborough, Massachusetts, United States of America.
authors.forename: Lisheng
authors.initials: L
authors.lastname: Peng
authors.affiliation: Neurobehavioral Toxicology Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Aberdeen, Maryland, United States of America.
authors.forename: Michael
authors.initials: M
authors.lastname: Adler
authors.affiliation: Department of Molecular Biosciences, University of Texas, Austin, Texas, United States of America.
authors.forename: Ann
authors.initials: A
authors.lastname: Demogines
authors.affiliation: Neurobehavioral Toxicology Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Aberdeen, Maryland, United States of America.
authors.forename: Andrew
authors.initials: A
authors.lastname: Borrell
authors.affiliation: Waisman Center, Department of Neuroscience, Department of Neurology, University of Wisconsin, Madison, Wisconsin, United States of America.
authors.forename: Huisheng
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Microbiology and Immunobiology, Harvard Medical School and Division of Neuroscience, New England Primate Research Center, Southborough, Massachusetts, United States of America.
authors.forename: Liang
authors.initials: L
authors.lastname: Tao
authors.affiliation: Department of Bacteriology, University of Wisconsin, Madison, Wisconsin, United States of America.
authors.forename: William H
authors.initials: WH
authors.lastname: Tepp
authors.affiliation: Waisman Center, Department of Neuroscience, Department of Neurology, University of Wisconsin, Madison, Wisconsin, United States of America.
authors.forename: Su-Chun
authors.initials: SC
authors.lastname: Zhang
authors.affiliation: Department of Bacteriology, University of Wisconsin, Madison, Wisconsin, United States of America.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Johnson
authors.affiliation: Department of Molecular Biosciences, University of Texas, Austin, Texas, United States of America.
authors.forename: Sara L
authors.initials: SL
authors.lastname: Sawyer
authors.affiliation: Department of Microbiology and Immunobiology, Harvard Medical School and Division of Neuroscience, New England Primate Research Center, Southborough, Massachusetts, United States of America.
authors.forename: Min
authors.initials: M
authors.lastname: Dong
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001905:Botulinum Toxins / Q000633:toxicity*; D003964:Diaphragm / Q000294:innervation / Q000378:metabolism / Q000473:pathology; D014644:Genetic Variation; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009046:Motor Neurons / Q000378:metabolism / Q000473:pathology; D010291:Paresis / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013045:Species Specificity; D050987:Vesicle-Associated Membrane Protein 1 / Q000235:genetics / Q000378:metabolism
chemical_list: C494704:VAMP1 protein, human; D050987:Vesicle-Associated Membrane Protein 1; C494771:vesicle-associated membrane protein 1, mouse; C494705:vesicle-associated membrane protein 1, rat; D001905:Botulinum Toxins