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Assembly of nicotinic α7 subunits in Xenopus oocytes is partially blocked at the tetramer level
Author(s) -
Nicke Annette,
Thurau Heike,
Sadtler Sven,
Rettinger Jürgen,
Schmalzing Günther
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2004.08.035
Subject(s) - xenopus , tetramer , protein subunit , receptor , nicotinic agonist , acetylcholine receptor , cys loop receptors , chemistry , microbiology and biotechnology , biophysics , biochemistry , biology , nicotinic acetylcholine receptor , enzyme , gene
The assembly of nicotinic α1β1γδ, α3β4, and α7 receptors and 5‐hydroxytryptamine 3A (5HT 3 A) receptors was comparatively evaluated in Xenopus oocytes by blue native PAGE analysis. While α1βγδ subunits, α3β4 subunits, and 5HT 3 A subunits combined efficiently to pentamers, α7 subunits existed in various assembly states including trimers, tetramers, pentamers, and aggregates. Only α7 subunits that completed the assembly process to homopentamers acquired complex‐type carbohydrates and appeared at the cell surface. We conclude that Xenopus oocytes have a limited capacity to guide the assembly of α7 subunits, but not 5HT 3 A subunits to homopentamers. Accordingly, ER retention of imperfectly assembled α7 subunits rather than inefficient routing of fully assembled α7 receptors to the cell surface limits surface expression levels of α7 nicotinic acetylcholine receptors.