Mapping the interaction sites between AMPA receptors and TARPs reveals a role for the receptor N-terminal domain in channel gating.
AMPA-type glutamate receptors (AMPARs) mediate fast neurotransmission at excitatory synapses. The extent and fidelity of postsynaptic depolarization triggered by AMPAR activation are shaped by AMPAR auxiliary subunits, including the transmembrane AMPAR regulatory proteins (TARPs). TARPs profoundly influence gating, an effect thought to be mediated by an interaction with the AMPAR ion channel and ligand binding domain (LBD). Here, we show that the distal N-terminal domain (NTD) contributes to TARP modulation. Alterations in the NTD-LBD linker result in TARP-dependent and TARP-selective changes in AMPAR gating. Using peptide arrays, we identify a TARP interaction region on the NTD and define the path of TARP contacts along the LBD surface. Moreover, we map key binding sites on the TARP itself and show that mutation of these residues mediates gating modulation. Our data reveal a TARP-dependent allosteric role for the AMPAR NTD and suggest that TARP binding triggers a drastic reorganization of the AMPAR complex.
Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
Ondrej
O
Cais
Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
Beatriz
B
Herguedas
Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK.
Karolina
K
Krol
Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK.
Stuart G
SG
Cull-Candy
Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK.
Mark
M
Farrant
Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK. Electronic address: ig@mrc-lmb.cam.ac.uk.
Ingo H
IH
Greger
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D015220:Calcium Channels / Q000737:chemistry / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D015640:Ion Channel Gating; D008969:Molecular Sequence Data; D011485:Protein Binding; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D018091:Receptors, AMPA / Q000737:chemistry* / Q000378:metabolism
C491911:Cacng2 protein, rat; C522274:Cacng4 protein, rat; D015220:Calcium Channels; D021122:Protein Subunits; D018091:Receptors, AMPA