Differential entry of botulinum neurotoxin A into neuronal and intestinal cells

Cell Microbiol. 2009 Feb;11(2):289-308. doi: 10.1111/j.1462-5822.2008.01253.x. Epub 2008 Oct 30.


Botulinum neurotoxins (BoNTs) are often acquired from the digestive tract and specifically target neuromuscular junctions where they cause an inhibition of acetylcholine release. A transcytotic mechanism has been evidenced in epithelial intestinal cells, which delivers whole BoNTs across the intestinal barrier, whereas BoNTs enter motoneurons through a pathway that permits the translocation of light chain into the cytosol. We used fluorescent BoNT/A C-terminal part of H chain (Hc) that mediates toxin binding to cell receptors to monitor toxin entry into NG108-15 neuronal cells as well as into Caco-2 and m-IC(cl2) intestinal cells. BoNT/A Hc receptors were found to be distributed in membrane structures closely associated to cholesterol-enriched microdomains, but distinct from detergent-resistant microdomains in both cell types. BoNT/A Hc was trapped into endocytic vesicles, which progressively migrated to a perinuclear area in NG108-15 cells, and in a more scattered manner in intestinal cells. In both cell types, BoNT/A Hc entered through a dynamin- and intersectin-dependent pathway, reached an early endosomal compartment labelled with early endosome antigen 1. In neuronal cells, BoNT/A Hc entered mainly via a clathrin-dependent pathway, in contrast to intestinal cells where it followed a Cdc42-dependent pathway, supporting a differential toxin routing in both cell types.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Vesicular Transport / metabolism
  • Botulinum Toxins, Type A / metabolism*
  • Cell Line
  • Cell Membrane / chemistry
  • Clathrin / metabolism
  • Cytoplasm / chemistry
  • Dynamins / metabolism
  • Epithelial Cells / metabolism*
  • Humans
  • Neurons / metabolism*
  • Protein Transport
  • Transport Vesicles / chemistry
  • cdc42 GTP-Binding Protein / metabolism


  • Adaptor Proteins, Vesicular Transport
  • Clathrin
  • intersectin 1
  • Botulinum Toxins, Type A
  • cdc42 GTP-Binding Protein
  • Dynamins