What is the cell surface receptor(s) for the different serotypes of botulinum neurotoxin?

The first step in the interaction of botulinum neurotoxin (BoNT) with target cells is its adherence to the cell surface. While the cell surface receptor(s) has not been unequivocably identified it does appear that different serotypes of BoNT may recognize different receptor(s). Gangliosides were the first molecules identified as potential BoNT receptors. However, more recent observations indicated that while gangliosides might affect binding they might not be the specific receptor. A protein component, either alone or in combination with gangliosides, may also be necessary. Evidence for the interaction of BoNT with specific cell surface molecules is presented and suggestions for future work to more completely define the receptor(s) are presented. Identification of the receptor(s) could lead to 1) development of inhibitors of the interaction, 2) better use of BoNT in the treatment of dystonias, and 3) use of BoNT in the targeting of drugs to the neuromuscular junction.