title: Domain organization and function in GluK2 subtype kainate receptors.
abstract: Glutamate receptor ion channels (iGluRs) are excitatory neurotransmitter receptors with a unique molecular architecture in which the extracellular domains assemble as a dimer of dimers. The structure of individual dimer assemblies has been established previously for both the isolated ligand-binding domain (LBD) and more recently for the larger amino terminal domain (ATD). How these dimers pack to form tetrameric assemblies in intact iGluRs has remained controversial. Using recently solved crystal structures for the GluK2 kainate receptor ATD as a guide, we performed cysteine mutant cross-linking experiments in full-length tetrameric GluK2 to establish how the ATD packs in a dimer of dimers assembly. A similar approach, using a full-length AMPA receptor GluA2 crystal structure as a guide, was used to design cysteine mutant cross-links for the GluK2 LBD dimer of dimers assembly. The formation of cross-linked tetramers in full-length GluK2 by combinations of ATD and LBD mutants which individually produce only cross-linked dimers suggests that subunits in the ATD and LBD layers swap dimer partners. Functional studies reveal that cross-linking either the ATD or the LBD inhibits activation of GluK2 and that, in the LBD, cross-links within and between dimers have different effects. These results establish that kainate and AMPA receptors have a conserved extracellular architecture and provide insight into the role of individual dimer assemblies in activation of ion channel gating.
authors.affiliation: Laboratory of Cellular and Molecular Neurophysiology, Department of Health and Human Services, Porter Neuroscience Research Center, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Utpal
authors.initials: U
authors.lastname: Das
authors.forename: Janesh
authors.initials: J
authors.lastname: Kumar
authors.forename: Mark L
authors.initials: ML
authors.lastname: Mayer
authors.forename: Andrew J R
authors.initials: AJ
authors.lastname: Plested
mesh_terms: D000818:Animals; D002460:Cell Line; D018360:Crystallography, X-Ray; D006801:Humans; D015640:Ion Channel Gating; D008024:Ligands; D008958:Models, Molecular; D009154:Mutation; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D051381:Rats; D018092:Kainic Acid Receptors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000097806:GluK2 Kainate Receptor
chemical_list: D008024:Ligands; D018092:Kainic Acid Receptors; D000097806:GluK2 Kainate Receptor
references.citation: EMBO J. 2009 Jun 17;28(12):1812-23
references.pmid: 19461580
references.citation: Cell. 2006 Oct 6;127(1):85-97
references.pmid: 17018279
references.citation: EMBO J. 2009 May 20;28(10):1518-30
references.pmid: 19339989
references.citation: Nature. 2007 Sep 20;449(7160):316-23
references.pmid: 17882215
references.citation: EMBO J. 2009 Dec 16;28(24):3910-20
references.pmid: 19910922
references.citation: Nature. 2005 Feb 3;433(7025):545-9
references.pmid: 15690046
references.citation: J Neurosci. 2009 Sep 30;29(39):12045-58
references.pmid: 19793963
references.citation: Nature. 2008 Mar 20;452(7185):375-9
references.pmid: 18322461
references.citation: Nat Struct Mol Biol. 2009 Jun;16(6):631-8
references.pmid: 19465914
references.citation: Nature. 2006 Mar 23;440(7083):456-62
references.pmid: 16554805
references.citation: Neuron. 1998 Oct;21(4):907-18
references.pmid: 9808475
references.citation: Nature. 2009 Jan 1;457(7225):111-4
references.pmid: 18987633
references.citation: J Neurosci. 1993 Aug;13(8):3496-509
references.pmid: 7688040
references.citation: Mol Pharmacol. 2009 Sep;76(3):534-42
references.pmid: 19561126
references.citation: Proc Natl Acad Sci U S A. 2005 Feb 1;102(5):1708-13
references.pmid: 15677325
references.citation: Proc Natl Acad Sci U S A. 2003 May 13;100(10):5736-41
references.pmid: 12730367
references.citation: Nature. 2009 Dec 10;462(7274):745-56
references.pmid: 19946266
references.citation: Neuron. 1993 Mar;10(3):491-500
references.pmid: 7681676
references.citation: Proc Natl Acad Sci U S A. 1995 Dec 19;92(26):12090-4
references.pmid: 8618850
references.citation: J Neurosci. 2009 Sep 23;29(38):11912-23
references.pmid: 19776277
references.citation: J Biol Chem. 2005 Apr 15;280(15):15053-60
references.pmid: 15703162
references.citation: J Mol Biol. 2004 Nov 19;344(2):435-42
references.pmid: 15522296
references.citation: J Mol Biol. 2009 Oct 9;392(5):1125-32
references.pmid: 19651138
references.citation: Pharmacol Rev. 1999 Mar;51(1):7-61
references.pmid: 10049997
references.citation: Nature. 2009 Jun 4;459(7247):703-7
references.pmid: 19404260
references.citation: Neuron. 2001 Jul 19;31(1):103-13
references.pmid: 11498054
references.citation: J Neurosci. 2003 Feb 15;23(4):1179-88
references.pmid: 12598606
references.citation: Nat Struct Mol Biol. 2006 Dec;13(12):1120-7
references.pmid: 17115050
references.citation: Nature. 2002 May 16;417(6886):245-53
references.pmid: 12015593
references.citation: J Mol Biol. 2005 Mar 4;346(4):967-89
references.pmid: 15701510
references.citation: Neuron. 2007 Mar 15;53(6):829-41
references.pmid: 17359918
references.citation: Neuron. 2005 Feb 17;45(4):539-52
references.pmid: 15721240
references.citation: J Neurosci. 2006 Mar 15;26(11):2852-61
references.pmid: 16540562
references.citation: Nat Neurosci. 2003 Aug;6(8):803-10
references.pmid: 12872125
references.citation: Science. 1998 Jun 5;280(5369):1596-9
references.pmid: 9616121
references.citation: Biol Chem. 2006 Feb;387(2):179-87
references.pmid: 16497150
references.citation: Neuron. 2008 Jun 12;58(5):720-35
references.pmid: 18549784
references.citation: Nature. 2009 Jul 30;460(7255):592-8
references.pmid: 19641588