Gating of nicotinic ACh receptors: latest insights into ligand binding and function.
Nicotinic acetylcholine receptors (nAChRs) are in the superfamily of cys-loop receptors, and are widely expressed in the nervous system where they participate in a variety of physiological functions, including regulating excitability and neurotransmitter release, as well as neuromuscular contraction. Members of the cys-loop family of receptors, which also includes the molluscan ACh-binding protein (AChBP), a soluble protein that is analogous to the extracellular ligand-binding domain of the cys-loop receptors, are pentameric assemblies of five subunits, with each subunit arranged around a central pore. The binding of ACh to the extracellular interface between two subunits induces channel opening. With the recent 4 A resolution of the Torpedo nAChR, and the crystal structure of the AChBP, much has been learned about the structure of the ligand-binding domain and the channel pore, as well as major structural rearrangements that may confer channel opening, including a major rearrangement of the C-loop within the ligand binding pocket, and perhaps other regions including the F-loop (the beta8-beta9 linker), the beta1-beta2 linker and the cys-loop. Here I will review the latest findings from my lab aimed at a further understanding of the function of the neuronal nAChR channels (and in particular the role of desensitization), and our search for novel AChBP species that may lead to a further understanding of the function of the cys-loop receptor family.
Yakel
Jerrel L
JL
Laboratory of Neurobiology, National Institute of Environmental Health Sciences, Department of Health and Human Services, PO Box 12233, Research Triangle Park, NC 27709, USA. yakel@niehs.nih.gov
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D015640:Ion Channel Gating; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011978:Receptors, Nicotinic / Q000737:chemistry* / Q000502:physiology*
C428944:AChBP protein, Lymnaea; D002352:Carrier Proteins; D011978:Receptors, Nicotinic