Maimone M M, Merlie J P
Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110.
Neuron. 1993 Jul;11(1):53-66. doi: 10.1016/0896-6273(93)90270-2.
The 43 kd postsynaptic protein (43K) plays a key role in the aggregation of muscle nicotinic acetylcholine receptors (AChRs) in the postsynaptic membrane of the neuromuscular junction. By transiently coexpressing 43K and a single AChR subunit (alpha, beta, gamma, or delta) in the quail fibroblast cell line, QT-6, we show that 43K interacts with each subunit to form cell surface clusters in which 43K and receptor subunit are precisely colocalized. Although the level of cell surface expression of single subunits is much lower than that of fully assembled receptor, the clustering of both single subunits and fully assembled AChR occurs efficiently. In addition, 43K-induced clustering is specific for AChR subunits. From these results, we conclude that each pentameric AChR has five potential sites for interacting with 43K during cluster formation.
43千道尔顿的突触后蛋白（43K）在神经肌肉接头突触后膜中肌肉烟碱型乙酰胆碱受体（AChRs）的聚集过程中起关键作用。通过在鹌鹑成纤维细胞系QT-6中瞬时共表达43K和单个AChR亚基（α、β、γ或δ），我们发现43K与每个亚基相互作用，形成细胞表面簇，其中43K和受体亚基精确共定位。尽管单个亚基的细胞表面表达水平远低于完全组装好的受体，但单个亚基和完全组装好的AChR的聚集都能高效发生。此外，43K诱导的聚集对AChR亚基具有特异性。从这些结果中，我们得出结论，在簇形成过程中，每个五聚体AChR有五个与43K相互作用的潜在位点。
