The Intracellular Domain of the Nicotinic Acetylcholine Receptor α Subunit Mediates Its Coclustering with Rapsyn

Muscle nicotinic acetylcholine receptors (AChRs) are immobilized at the neuromuscular junction in high-density clusters by rapsyn, a 43-kDa protein located at the cytoplasmic face of the postsynaptic membrane. When expressed in nonmuscle cells, rapsyn induces the aggregation of both assembled and un...

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Bibliographic Details
Published in:Molecular and cellular neuroscience 1999-10, Vol.14 (4-5), p.340-354
Main Authors: Maimone, Margaret M., Enigk, Rebecca E.
Format: Article
Language:English
Subjects:
Animals
Antibodies, Monoclonal
Cell Line
DNA Primers
Fibroblasts - chemistry
Fibroblasts - cytology
Fibroblasts - metabolism
Fluorescent Antibody Technique
Gene Deletion
Kv1.2 Potassium Channel
Muscle Proteins - metabolism
Mutagenesis - physiology
Plasmids
Potassium Channels - analysis
Potassium Channels - genetics
Potassium Channels - immunology
Potassium Channels, Voltage-Gated
Protein Structure, Tertiary
Quail
rapsyn
Receptors, Nicotinic - chemistry
Receptors, Nicotinic - genetics
Receptors, Nicotinic - metabolism
Recombinant Fusion Proteins - analysis
Recombinant Fusion Proteins - immunology
Recombinant Fusion Proteins - metabolism
Transfection
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Summary:Muscle nicotinic acetylcholine receptors (AChRs) are immobilized at the neuromuscular junction in high-density clusters by rapsyn, a 43-kDa protein located at the cytoplasmic face of the postsynaptic membrane. When expressed in nonmuscle cells, rapsyn induces the aggregation of both assembled and unassembled AChR subunits. Here, we investigated the mechanism of rapsyn-induced clustering of the AChR α subunit by testing a series of α subunit mutants for colocalization with rapsyn patches in transfected QT6 cells. Partial or total deletion of the large intracellular domain of the α subunit dramatically reduced its ability to colocalize with rapsyn patches. Furthermore, insertion of the α subunit large intracellular domain into a potassium channel resulted in a significant increase in the channel's colocalization with rapsyn patches. We conclude that the large intracellular domain of the α subunit plays an important role in mediating rapsyn-induced coclustering of the AChR α subunit.
ISSN:1044-7431
1095-9327
DOI:10.1006/mcne.1999.0779