Intracellular complexes of the beta2 subunit of the nicotinic acetylcholine receptor in brain identified by proteomics.
Nicotine acetylcholine receptors (nAChRs) comprise a family of ligand-gated channels widely expressed in the mammalian brain. The beta2 subunit is an abundant protein subunit critically involved in the cognitive and behavioral properties of nicotine as well as in the mechanisms of nicotine addiction. In this work, we used matrix-assisted laser desorption ionization time-of-flight tandem mass spectrometry (MALDI-TOF-TOF MS/MS) to uncover protein interactions of the intracellular loop of the beta2 subunit and components of immunoprecipitated beta2-nAChR complexes from mouse brain. Using the beta2-knockout mouse to exclude nonspecific binding to the beta2 antibody, we identify 21 nAChR-interacting proteins (NIPs) expressed in brain. Western blot analysis confirmed the association between the beta2 subunit and candidate NIPs. Based on their functional profiles, the hypothesis is suggested that the identified NIPs can regulate the trafficking and signaling of the beta2-nAChR. Interactions of the beta2 subunit with NIPs such as G protein alpha, G protein-regulated inducer of neurite outgrowth 1, and G protein-activated K(+) channel 1 suggest a link between nAChRs and cellular G protein pathways. These findings reveal intracellular interactions of the beta2 subunit and may contribute to the understanding of the mechanisms of nAChR signaling and trafficking in neurons.
Kabbani
Nadine
N
Récepteurs et Cognition, Centre National de la Recherche Scientifique Unité de Recherche Associée 2182, Institut Pasteur, 75724 Paris, France. kabbani.nadine@ijm.jussieu.fr
Woll
Matthew P
MP
Levenson
Robert
R
Lindstrom
Jon M
JM
Changeux
Jean-Pierre
JP
D000818:Animals; D001921:Brain / Q000378:metabolism*; D047468:Immunoprecipitation; D051379:Mice; D018345:Mice, Knockout; D025941:Protein Interaction Mapping; D021381:Protein Transport; D011506:Proteins / Q000032:analysis / Q000378:metabolism; D040901:Proteomics; D011978:Receptors, Nicotinic / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D011506:Proteins; D011978:Receptors, Nicotinic