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Identification of amino acid residues important for assembly of GABA A receptor α1 and γ2 subunits
Author(s) -
SartoJackson Isabella,
Ramerstorfer Joachim,
Ernst Margot,
Sieghart Werner
Publication year - 2006
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2005.03626.x
Subject(s) - cys loop receptors , receptor , protein subunit , hek 293 cells , biochemistry , residue (chemistry) , chemistry , amino acid , amino acid residue , stereochemistry , acetylcholine receptor , peptide sequence , biology , gene , nicotinic acetylcholine receptor
Comparative models of GABA A receptors composed of α1β3γ2 subunits were generated using the acetylcholine‐binding protein (AChBP) as a template and were used for predicting putative engineered cross‐link sites between the α1 and the γ2 subunit. The respective amino acid residues were substituted by cysteines and disulfide bond formation between subunits was investigated on co‐transfection into human embryonic kidney (HEK) cells. Although disulfide bond formation between subunits could not be observed, results indicated that mutations studied influenced assembly of GABA A receptors. Whereas residue α1A108 was important for the formation of assembly intermediates with β3 and γ2 subunits consistent with its proposed location at the α1(+) side of GABA A receptors, residues γ2T125 and γ2P127 were important for assembly with β3 subunits. Mutation of each of these residues also caused an impaired expression of receptors at the cell surface. In contrast, mutated residues α1F99C, α1S106C or γ2T126C only impaired the formation of receptors at the cell surface when co‐expressed with subunits in which their predicted interaction partner was also mutated. These data are consistent with the prediction that the mutated residue pairs are located close to each other.