Shen N V, Chen X, Boyer M M, Pfaffinger P J
Division of Neuroscience, Baylor College of Medicine, Houston, Texas 77030.
Neuron. 1993 Jul;11(1):67-76. doi: 10.1016/0896-6273(93)90271-r.
An understanding of K+ channel structure is a critical step in developing an appreciation of the function and regulation of these proteins. We have begun a biochemical analysis of the early steps in K+ channel formation following translation into endoplasmic reticulum membranes. In our experiments, a series of K+ channel subunit protein deletions were constructed and then tested for posttranslational processing and assembly. We find that all deletions containing the S1 domain are inserted into the membrane. The loop between S1 and S2 is glycosylated; thus, this segment is topologically extracellular. Translated subunit proteins mix in the membrane, then assemble into tetramers. This subunit assembly is critically driven by a conserved, self-tetramerizing sequence in the N-terminal cytoplasmic region, which we have named the tetramerization 1 domain.
了解钾离子通道结构是认识这些蛋白质的功能和调节机制的关键一步。我们已经开始对钾离子通道在翻译后插入内质网膜的早期步骤进行生化分析。在我们的实验中，构建了一系列钾离子通道亚基蛋白缺失体，然后检测其翻译后加工和组装情况。我们发现，所有包含S1结构域的缺失体都能插入膜中。S1和S2之间的环被糖基化；因此，该片段在拓扑结构上位于细胞外。翻译后的亚基蛋白在膜中混合，然后组装成四聚体。这种亚基组装主要由N端胞质区域中一个保守的、自我四聚化的序列驱动，我们将其命名为四聚化1结构域。
