Synaptotagmins I and II Mediate Entry of Botulinum Neurotoxin B into Cells

• Published in: The Journal of cell biology Vol. 162; no. 7; pp. 1293 - 1303
• Main Authors: Dong, Min, Richards, David A., Goodnough, Michael C., Tepp, William H., Johnson, Eric A., Chapman, Edwin R.
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 29.09.2003; The Rockefeller University Press
• Subjects: Amino Acid Sequence; Animals; Antibodies; Botulinum Toxins - pharmacokinetics; Botulinum Toxins, Type A; Botulism; Botulism - metabolism; Calcium-Binding Proteins; Cell lines; Cells; Cellular biology; Cytoplasmic Vesicles - metabolism; Female; Gangliosides; Gangliosides - metabolism; Membrane Glycoproteins - chemistry; Membrane Glycoproteins - genetics; Membrane Glycoproteins - metabolism; Mice; Molecular Sequence Data; Motor Neurons - metabolism; Nerve Tissue Proteins - chemistry; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; Neurons; Neurotoxins; PC12 Cells; Protein Structure, Tertiary; Proteins; Rats; Receptors; Synaptotagmin II; Synaptotagmins; Toxins
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.200305098

Botulinum neurotoxins (BoNTs) cause botulism by entering neurons and cleaving proteins that mediate neurotransmitter release; disruption of exocytosis results in paralysis and death. The receptors for BoNTs are thought to be composed of both proteins and gangliosides; however, protein components that mediate toxin entry have not been identified. Using gain-of-function and loss-of-function approaches, we report here that the secretory vesicle proteins, synaptotagmins (syts) I and II, mediate the entry of BoNT/B (but not BoNT/A or E) into PC12 cells. Further, we demonstrate that BoNT/B entry into PC12 cells and rat diaphragm motor nerve terminals was activity dependent and can be blocked using fragments of syt II that contain the BoNT/B-binding domain. Finally, we show that syt II fragments, in conjunction with gangliosides, neutralized BoNT/B in intact mice. These findings establish that syts I and II can function as protein receptors for BoNT/B.