Griffon N, Büttner C, Nicke A, Kuhse J, Schmalzing G, Betz H
Department of Neurochemistry, Max-Planck-Institute for Brain Research, Deutschordenstrasse 46, D-60528 Frankfurt am Main, Germany.
EMBO J. 1999 Sep 1;18(17):4711-21. doi: 10.1093/emboj/18.17.4711.
The inhibitory glycine receptor (GlyR) is a pentameric transmembrane protein composed of homologous alpha and beta subunits. Single expression of alpha subunits generates functional homo-oligomeric GlyRs, whereas the beta subunit requires a co-expressed alpha subunit to assemble into hetero-oligomeric channels of invariant stoichiometry (alpha(3)beta(2)). Here, we identified eight amino acid residues within the N-terminal region of the alpha1 subunit that are required for the formation of homo-oligomeric GlyR channels. We show that oligomerization and N-glycosylation of the alpha1 subunit are required for transit from the endoplasmic reticulum to the Golgi apparatus and later compartments, and that addition of simple carbohydrate side chains occurs prior to GlyR subunit assembly. Our data are consistent with both intersubunit surface and conformational differences determining the different assembly behaviour of GlyR alpha and beta subunits.
抑制性甘氨酸受体（GlyR）是一种由同源的α和β亚基组成的五聚体跨膜蛋白。α亚基的单独表达可产生功能性同聚体GlyRs，而β亚基需要与共同表达的α亚基组装成化学计量恒定的异聚体通道（α(3)β(2)）。在这里，我们确定了α1亚基N端区域内形成同聚体GlyR通道所需的八个氨基酸残基。我们表明，α1亚基的寡聚化和N-糖基化是其从内质网转运到高尔基体及后续区室所必需的，并且简单碳水化合物侧链的添加发生在GlyR亚基组装之前。我们的数据与亚基间表面和构象差异决定GlyRα和β亚基不同组装行为的观点一致。
