Proteomic Analysis of an α7 Nicotinic Acetylcholine Receptor Interactome

The alpha 7 nicotinic acetylcholine receptor (nAChR) is well established as the principal high-affinity alpha-bungarotoxin-binding protein in the mammalian brain. We isolated carbachol-sensitive alpha-bungarotoxin-binding complexes from total mouse brain tissue by affinity immobilization followed by selective elution, and these proteins were fractionated by SDS-PAGE. The proteins in subdivided gel lane segments were tryptically digested, and the resulting peptides were analyzed by standard mass spectrometry. We identified 55 proteins in wild-type samples that were not present in comparable brain samples from alpha 7 nAChR knockout mice that had been processed in a parallel fashion. Many of these 55 proteins are novel proteomic candidates for interaction partners of the alpha 7 nAChR, and many are associated with multiple signaling pathways that may be implicated in alpha 7 function in the central nervous system. The newly identified potential protein interactions, together with the general methodology that we introduce for alpha-bungarotoxin-binding protein complexes, form a new platform for many interesting follow-up studies aimed at elucidating the physiological role of neuronal alpha 7 nAChRs.