Immunoaffinity purification of gamma-aminobutyric acidA (GABAA) receptors containing gamma 1-subunits. Evidence for the presence of a single type of gamma-subunit in GABAA receptors

J Biol Chem. 1994 Oct 14;269(41):25777-82.


Two polyclonal antibodies were raised against the gamma 1-subunit of gamma-aminobutyric acidA (GABAA) receptors. One of these antibodies could be used for the immunopurification of GABAA receptors containing gamma 1-subunits. These receptors exhibited [3H]muscimol and [3H]flunitrazepam binding, and their benzodiazepine binding properties were dramatically different from those of receptors precipitated by anti-gamma 2- or anti-gamma 3-antibodies. Western blot analysis of the immunopurified GABAA receptors indicated that the gamma 1-subunit exhibits an apparent molecular mass of 45-51 kDa. Furthermore, in addition to gamma 1-subunits, beta 2/3-, alpha 1-, alpha 2-, alpha 3-, and alpha 5-subunits could be detected in immunoaffinity column eluates from total brain. In contrast, gamma 2- or gamma 3-subunits could not be identified in GABAA receptors immunopurified by anti-gamma 1-antibodies. Similarly, gamma 1- and gamma 3-subunits or gamma 1- and gamma 2-subunits could not be identified in GABAA receptors purified by anti-gamma 2- or anti-gamma 3-antibodies, respectively. These data seem to indicate that GABAA receptors contain only a single type of gamma-subunit.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibody Specificity
  • Base Sequence
  • Blotting, Western
  • Brain Chemistry*
  • Chromatography, Affinity
  • Clonazepam / metabolism
  • Enzyme-Linked Immunosorbent Assay
  • Flumazenil / metabolism
  • Flunitrazepam / metabolism
  • Immunologic Techniques
  • Molecular Sequence Data
  • Molecular Weight
  • Muscimol / metabolism
  • Peptide Fragments / biosynthesis
  • Peptide Fragments / genetics
  • Peptide Fragments / immunology
  • Protein Conformation
  • Rats
  • Receptors, GABA-A / classification
  • Receptors, GABA-A / immunology
  • Receptors, GABA-A / isolation & purification*
  • Receptors, GABA-A / metabolism
  • Recombinant Fusion Proteins / biosynthesis
  • Recombinant Fusion Proteins / immunology


  • Peptide Fragments
  • Receptors, GABA-A
  • Recombinant Fusion Proteins
  • Muscimol
  • Flumazenil
  • Clonazepam
  • Flunitrazepam