Endocytosis, trafficking and exocytosis of intact full-length Botulinum neurotoxin type A in cultured rat neurons

Luis Solabre Valois, Kevin A Wilkinson, Yasuko Nakamura, Jeremy M Henley

Research output: Contribution to journalArticle (Academic Journal)

33 Downloads (Pure)

Abstract

Botulinum toxin A (BoNT/A) is a potent neurotoxin that acts primarily by silencing synaptic transmission by blocking neurotransmitter release. BoNT/A comprises a light chain (LC/A) intracellular protease and a heavy chain (HC/A) composed of a receptor binding domain (HCC/A) and a translocation domain (HCN/A) that mediates cell entry. Following entry into the neuron, the disulphide bond linking the two peptide chains is reduced to release the LC/A. To gain better insight into the trafficking and fate of BoNT/A before dissociation we have
used a catalytically inactive, non-toxic full-length BoNT/A(0) mutant. Our data confirm that BoNT/A(0) enters cortical neurons both in an activity-dependent manner and via a pathway dependent on fibroblast growth factor receptor 3 (Fgfr3) signalling. We demonstrate that both dynamin-dependent endocytosis and lipid rafts are involved in BoNT/A internalisation and that full-length BoNT/A(0) traffics to early endosomes. Furthermore, while a proportion of BoNT/A remains stable in neurons for 3 days, BoNT/A degradation is primarily mediated by the proteasome. Finally, we demonstrate that a fraction of the endocytosed full-length BoNT/A(0) is capable of exiting the cell to intoxicate other neurons. Together, our data shed new light on the entry routes, trafficking and degradation of BoNT/A, and confirm that trafficking properties previously described for the isolated HCC/A receptor binding domain of are also applicable to the intact, full-length toxin.
Original languageEnglish
Pages (from-to)80-87
Number of pages8
JournalNeuroToxicology
Volume78 (2020)
Early online date20 Feb 2020
DOIs
Publication statusE-pub ahead of print - 20 Feb 2020

Keywords

  • Neuron
  • Botulinum neurotoxin type A
  • BoNT/A
  • degradation
  • endocytosis

Fingerprint Dive into the research topics of 'Endocytosis, trafficking and exocytosis of intact full-length Botulinum neurotoxin type A in cultured rat neurons'. Together they form a unique fingerprint.

  • Cite this