title: Acetylcholine binding protein (AChBP): a secreted glial protein that provides a high-resolution model for the extracellular domain of pentameric ligand-gated ion channels.
abstract: 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.
authors.affiliation: Division of Molecular Carcinogenesis, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands. t.sixma@nki.nl
authors.forename: Titia K
authors.initials: TK
authors.lastname: Sixma
authors.forename: August B
authors.initials: AB
authors.lastname: Smit
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000145:classification / Q000378:metabolism*; D015640:Ion Channel Gating / Q000502:physiology*; D007473:Ion Channels / Q000737:chemistry* / Q000378:metabolism*; D008024:Ligands; D008969:Molecular Sequence Data; D009457:Neuroglia / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D018079:Receptors, GABA / Q000737:chemistry / Q000378:metabolism; D018009:Receptors, Glycine / Q000737:chemistry / Q000378:metabolism; D011978:Receptors, Nicotinic / Q000737:chemistry / Q000378:metabolism; D011985:Receptors, Serotonin / Q000737:chemistry / Q000378:metabolism; D012908:Snails / Q000737:chemistry / Q000378:metabolism; D013045:Species Specificity; D009435:Synaptic Transmission / Q000502:physiology*
chemical_list: C428944:AChBP protein, Lymnaea; D002352:Carrier Proteins; D007473:Ion Channels; D008024:Ligands; D018079:Receptors, GABA; D018009:Receptors, Glycine; D011978:Receptors, Nicotinic; D011985:Receptors, Serotonin; C078730:serotonin 5 receptor