A eukaryotic specific transmembrane segment is required for tetramerization in AMPA receptors

Salussolia, C. L., Gan, Q., Kazi, R., Singh, P., Allopenna, J., Furukawa, H., Wollmuth, L. P. (2013) A eukaryotic specific transmembrane segment is required for tetramerization in AMPA receptors. Journal of Neuroscience, 33 (23). pp. 9840-9845. ISSN 02706474

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URL: http://www.ncbi.nlm.nih.gov/pubmed/23739980
DOI: 10.1523/JNEUROSCI.2626-12.2013

Abstract

Most fast excitatory synaptic transmission in the nervous system is mediated by glutamate acting through ionotropic glutamate receptors (iGluRs). iGluRs (AMPA, kainate, and NMDA receptor subtypes) are tetrameric assemblies, formed as a dimer of dimers. Still, the mechanism underlying tetramerization-the necessary step for the formation of functional receptors that can be inserted into the plasma membrane-is unknown. All eukaryotic compared to prokaryotic iGluR subunits have an additional transmembrane segment, theM4segment, which positions the physiologically critical C-terminal domain on the cytoplasmic side of the membrane.AMPAreceptor (AMPAR) subunits lacking M4 do not express on the plasma membrane. Here, we show that these constructs are retained in the endoplasmic reticulum, the major cellular compartment mediating protein oligomerization. Using approaches to assay the native oligomeric state of AMPAR subunits, we find that subunits lacking M4 or containing single amino acid substitutions along an "interacting" face of the M4 helix that block surface expression no longer tetramerize in either homomeric or heteromeric assemblies. In contrast, subunit dimerization appears to be largely intact. These experiments define the M4 segment as a unique functional unit in AMPARs that is required for the critical dimer-to-tetramer transition. © 2013 the authors.

Item Type: Paper
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > AMPA receptor
bioinformatics > genomics and proteomics > genetics & nucleic acid processing
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types
organs, tissues, organelles, cell types and functions > tissues types and functions
organs, tissues, organelles, cell types and functions > tissues types and functions > transport > trans-membrane transport
CSHL Authors:
Communities: CSHL labs > Furukawa lab
Depositing User: Matt Covey
Date Deposited: 24 Jun 2013 20:13
Last Modified: 17 Sep 2013 18:53
PMCID: PMC3714855
Related URLs:
URI: http://repository.cshl.edu/id/eprint/28362

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