Expression of dopamine D3 receptor dimers and tetramers in brain and in transfected cells

Esther A. Nimchinsky, Patrick R. Hof, William G M Janssen, John Morrison, Claudia Schmauss

Research output: Contribution to journalArticle

148 Scopus citations

Abstract

The expression and characteristics of the dopamine D3 receptor protein were studied in brain and in stably transfected GH3 cells. Monoclonal antibodies were used for immunoprecipitation and immunoblot experiments. Immunoprecipitates obtained from primate and rodent brain tissues contain a low molecular weight D3 protein and one or two larger protein species whose molecular mass are integral multiples of the low molecular weight protein and thus appear to have resulted from dimerization and tetramerization of a D3 monomer. Whereas D3 receptor multimers were found to be abundantly expressed in brain, the major D3 immunoreactivity expressed in stable D3-expressing rat GH3 cells was found to be a monomer. However, multimeric D3 receptor species with electrophoretic mobilities similar to those expressed in brain were also seen in D3-expressing GH3 cells when a truncated D3-like protein (named D(3nf))was co-expressed in these cells. Furthermore, results from immunoprecipitation experiments with D3- and D(3nf)-specific antibodies show that the higher-order D3 proteins extracted from brain and D3/D(3nf) double transfectants also contain D(3nf)immunoreactivity, and immunocytochemical studies show that the expression of D3 and D(3nf) immunoreactivities overlaps substantially in monkey and rat cortical neurons. Altogether, these data show oligomeric D3 receptor protein expression in vivo and they suggest that at least some of these oligomers are heteroligomeric protein complexes containing D3 and the truncated D(3nf) protein.

Original languageEnglish (US)
Pages (from-to)29229-29237
Number of pages9
JournalJournal of Biological Chemistry
Volume272
Issue number46
DOIs
StatePublished - Nov 14 1997
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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