title: Probing Intersubunit Interfaces in AMPA-subtype Ionotropic Glutamate Receptors.
abstract: AMPA subtype ionotropic glutamate receptors (iGluRs) mediate the majority of fast neurotransmission across excitatory synapses in the central nervous system. Each AMPA receptor is composed of four multi-domain subunits that are organized into layers of two amino-terminal domain (ATD) dimers, two ligand-binding domain (LBD) dimers, transmembrane domains and carboxy-terminal domains. We introduced cysteine substitutions at the intersubunit interfaces of AMPA receptor subunit GluA2 and confirmed substituted cysteine crosslink formation by SDS-PAGE. The functional consequence of intersubunit crosslinks was assessed by recording GluA2-mediated currents in reducing and non-reducing conditions. Strong redox-dependent changes in GluA2-mediated currents were observed for cysteine substitutions at the LBD dimer-dimer interface but not at the ATD dimer-dimer interface. We conclude that during gating, LBD dimers undergo significant relative displacement, while ATD dimers either maintain their relative positioning, or their relative displacement has no appreciable effect on AMPA receptor function.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University 650 West 168th Street, New York, NY 10032.
authors.forename: Maria V
authors.initials: MV
authors.lastname: Yelshanskaya
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University 650 West 168th Street, New York, NY 10032.
authors.forename: Kei
authors.initials: K
authors.lastname: Saotome
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University 650 West 168th Street, New York, NY 10032.
authors.forename: Appu K
authors.initials: AK
authors.lastname: Singh
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University 650 West 168th Street, New York, NY 10032.
authors.forename: Alexander I
authors.initials: AI
authors.lastname: Sobolevsky
mesh_terms: D019943:Amino Acid Substitution; D002460:Cell Line; D055786:Gene Knockout Techniques; D006801:Humans; D015640:Ion Channel Gating; D008958:Models, Molecular; D009154:Mutation; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D021122:Protein Subunits / Q000737:chemistry* / Q000378:metabolism*; D018091:Receptors, AMPA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D021122:Protein Subunits; D018091:Receptors, AMPA