title: Liposome reconstitution and modulation of recombinant N-methyl-D-aspartate receptor channels by membrane stretch.
abstract: In this study, the heteromeric N-methyl-D-aspartate (NMDA) receptor channels composed of NR1a and NR2A subunits were expressed, purified, reconstituted into liposomes, and characterized by using the patch clamp technique. The protein exhibited the expected electrophysiological profile of activation by glutamate and glycine and internal Mg2+ blockade. We demonstrated that the mechanical energy transmitted to membrane-bound NMDA receptor channels can be exerted directly by tension developed in the lipid bilayer. Membrane stretch and application of arachidonic acid potentiated currents through NMDA receptor channels in the presence of intracellular Mg2+. The correlation of membrane tension induced by either mechanical or chemical stimuli with the physiological Mg2+ block of the channel suggests that the synaptic transmission can be altered if NMDA receptor complexes experience local changes in bilayer thickness caused by dynamic targeting to lipid microdomains, electrocompression, or chemical modification of the cell membranes. The ability to study gating properties of NMDA receptor channels in artificial bilayers should prove useful in further study of structure-function relationships and facilitate discoveries of new therapeutic agents for treatment of glutamate-mediated excitotoxicity or analgesic therapies.
authors.affiliation: School of Biomedical Sciences, Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: Anna
authors.initials: A
authors.lastname: Kloda
authors.forename: Linda
authors.initials: L
authors.lastname: Lua
authors.forename: Rhonda
authors.initials: R
authors.lastname: Hall
authors.forename: David J
authors.initials: DJ
authors.lastname: Adams
authors.forename: Boris
authors.initials: B
authors.lastname: Martinac
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000737:chemistry; D002462:Cell Membrane / Q000378:metabolism*; D004594:Electrophysiology; D007313:Insecta; D008051:Lipid Bilayers; D008081:Liposomes / Q000737:chemistry*; D008274:Magnesium / Q000737:chemistry; D008954:Models, Biological; D018408:Patch-Clamp Techniques; D010713:Phosphatidylcholines / Q000737:chemistry; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D015398:Signal Transduction
chemical_list: D008051:Lipid Bilayers; D008081:Liposomes; D010713:Phosphatidylcholines; D016194:Receptors, N-Methyl-D-Aspartate; D011994:Recombinant Proteins; D016718:Arachidonic Acid; C024990:asolectin; D008274:Magnesium