Acetylcholine binding protein (AChBP): a secreted glial protein that provides a high-resolution model for the extracellular domain of pentameric ligand-gated ion channels

Annu Rev Biophys Biomol Struct. 2003;32:311-34. doi: 10.1146/annurev.biophys.32.110601.142536. Epub 2003 Feb 21.


Acetylcholine binding protein (AChBP) has recently been identified from molluskan glial cells. Glial cells secrete it into cholinergic synapses, where it plays a role in modulating synaptic transmission. This novel mechanism resembles glia-dependent modulation of glutamate synapses, with several key differences. AChBP is a homolog of the ligand binding domain of the pentameric ligand-gated ion-channels. The crystal structure of AChBP provides the first high-resolution structure for this family of Cys-loop receptors. Nicotinic acetylcholine receptors and related ion-channels such as GABAA, serotonin 5HT3, and glycine can be interpreted in the light of the 2.7 A AChBP structure. The structural template provides critical details of the binding site and helps create models for toxin binding, mutational effects, and molecular gating.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Carrier Proteins / chemistry*
  • Carrier Proteins / classification
  • Carrier Proteins / metabolism*
  • Ion Channel Gating / physiology*
  • Ion Channels / chemistry*
  • Ion Channels / metabolism*
  • Ligands
  • Molecular Sequence Data
  • Neuroglia / chemistry
  • Neuroglia / metabolism
  • Protein Binding
  • Protein Structure, Tertiary
  • Receptors, GABA / chemistry
  • Receptors, GABA / metabolism
  • Receptors, Glycine / chemistry
  • Receptors, Glycine / metabolism
  • Receptors, Nicotinic / chemistry
  • Receptors, Nicotinic / metabolism
  • Receptors, Serotonin / chemistry
  • Receptors, Serotonin / metabolism
  • Snails / chemistry
  • Snails / metabolism
  • Species Specificity
  • Synaptic Transmission / physiology*


  • AChBP protein, Lymnaea
  • Carrier Proteins
  • Ion Channels
  • Ligands
  • Receptors, GABA
  • Receptors, Glycine
  • Receptors, Nicotinic
  • Receptors, Serotonin
  • serotonin 5 receptor