title: Disruption of lipid rafts enhances activity of botulinum neurotoxin serotype A.
abstract: Botulinum neurotoxin serotype A (BoNT/A), one of seven serotypes of botulinum neurotoxin, is taken up by neurons of the peripheral nervous system. Within the neurons it catalyzes cleavage of the synaptosomal-associated protein having a mass of 25kDa, SNAP-25, thereby blocking neurotransmission. BoNT/A has been shown to interact with SV2, as well as gangliosides that are often found in lipid rafts. Lipid rafts are microdomains that can be found on the outer leaflet of the plasma membrane and are enriched in cholesterol and glycosphingolipids. To determine whether lipid rafts are needed for BoNT/A activity, those associated with the plasma membranes of murine N2a neuroblastoma cells were disrupted using either methyl-beta-cyclodextrin or filipin. Disruption of cholesterol-containing lipid rafts by either reagent did not prevent the action of BoNT/A on N2a cells, in fact activity was enhanced. While our results indicate that disruption of lipid rafts enhances BoNT/A activity, disruption of clathrin-dependent endocytosis appeared to be inhibitory.
authors.affiliation: Department of Biochemistry and Molecular Biology, H171, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Petro
authors.forename: Maureen A
authors.initials: MA
authors.lastname: Dyer
authors.forename: Brian C
authors.initials: BC
authors.lastname: Yowler
authors.forename: Cara-Lynne
authors.initials: CL
authors.lastname: Schengrund
mesh_terms: D000818:Animals; D019274:Botulinum Toxins, Type A / Q000633:toxicity*; D045744:Cell Line, Tumor; D002772:Cholera Toxin / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism; D002966:Clathrin / Q000037:antagonists & inhibitors; D022163:Clathrin-Coated Vesicles / Q000187:drug effects / Q000502:physiology; D004705:Endocytosis / Q000502:physiology; D005372:Filipin / Q000494:pharmacology; D005677:G(M1) Ganglioside / Q000378:metabolism; D021962:Membrane Microdomains / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D051379:Mice; D009498:Neurotoxins / Q000633:toxicity*; D050825:Synaptosomal-Associated Protein 25 / Q000378:metabolism; D047392:beta-Cyclodextrins / Q000494:pharmacology
chemical_list: D002966:Clathrin; D009498:Neurotoxins; C494209:Snap25 protein, mouse; D050825:Synaptosomal-Associated Protein 25; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D005677:G(M1) Ganglioside; D005372:Filipin; D002772:Cholera Toxin; D002784:Cholesterol; D019274:Botulinum Toxins, Type A