Gehle V M, Sumikawa K
Department of Psychobiology, University of California, Irvine 92717.
Brain Res Mol Brain Res. 1991 Aug;11(1):17-25. doi: 10.1016/0169-328x(91)90016-q.
The role of the conserved N-glycosylation site on each subunit of the Torpedo acetylcholine receptor (AChR) in the biogenesis and function of the receptor was examined by expressing site-directed mutant subunits in Xenopus oocytes. Different mutant subunits caused different effects. The most striking effect was seen with the mutant gamma subunit which, when co-expressed with alpha, beta, and delta subunits, caused degradation of all the subunits. N-Glycosylation of the other subunits appears to contribute to stability of the subunits and/or efficient insertion of the receptor into the plasma membrane, but is not required for assembly. The AChRs containing the mutant alpha subunit formed functional ion channels in the plasma membrane and their activity could be blocked by alpha-bungarotoxin (alpha-BuTX). Thus, attachment of a carbohydrate moiety at the conserved N-glycosylation site is not an absolute requirement for the formation of ACh and alpha-BuTX binding sites.
通过在非洲爪蟾卵母细胞中表达定点突变亚基，研究了电鳐乙酰胆碱受体（AChR）每个亚基上保守的N - 糖基化位点在受体生物合成和功能中的作用。不同的突变亚基产生了不同的影响。最显著的影响出现在突变的γ亚基上，当它与α、β和δ亚基共表达时，会导致所有亚基的降解。其他亚基的N - 糖基化似乎有助于亚基的稳定性和/或将受体有效插入质膜，但组装过程并不需要它。含有突变α亚基的AChR在质膜中形成了功能性离子通道，其活性可被α - 银环蛇毒素（α - BuTX）阻断。因此，在保守的N - 糖基化位点连接碳水化合物部分并非形成ACh和α - BuTX结合位点的绝对必要条件。
