Katz F N, Rothman J E, Knipe D M, Lodish H F
J Supramol Struct. 1977;7(3-4):353-70. doi: 10.1002/jss.400070308.
The glycoprotein (G) of vesicular stomatitis virus (VSV) is synthesized on membrane-bound polyribosomes. Approximately 30 min after its synthesis, it reaches the surface plasma membrane where it is incorporated into budding virus. The first part of this paper focuses on the 2 intracellular, membrane-bound, glycosylated forms of the glycoprotein which are intermediates in its biogenesis. All glycosylation and processing is completed in the smooth microsome fraction before the protein reaches the surface. Next, we turn to the mechanism by which G is synthesized on membrane-bound polyribosomes. All of the G mRNA is bound to membranes, and studies with puromycin suggest that this attachment of G mRNA is mediated by the nascent glycoprotein chain. After its synthesis G is a transmembrane protein with about 30 amino acids at the carboxyl terminus remaining on the cytoplasmic side of the endoplasmic reticulum. Since 95% of the glycoprotein, containing the carbohydrate residues, is resistant to attack by external proteases, it appears to be within the lumen of the endoplasmic reticulum or embedded within the lipid bilayer. Finally, we show that synthesis, glycosylation, and proper asymmetric insertion of G into the ER can be achieved in cell-free extracts. Both glycosylation of G and proper insertion into the ER membrane in this cell-free system require concomitant protein synthesis.
水泡性口炎病毒（VSV）的糖蛋白（G）在膜结合多核糖体上合成。合成后约30分钟，它到达表面质膜，在那里被整合到出芽的病毒中。本文的第一部分重点关注糖蛋白的两种细胞内、膜结合、糖基化形式，它们是其生物合成的中间体。在蛋白质到达表面之前，所有糖基化和加工都在光滑微粒体部分完成。接下来，我们转向G在膜结合多核糖体上合成的机制。所有G mRNA都与膜结合，用嘌呤霉素进行的研究表明，G mRNA的这种附着是由新生糖蛋白链介导的。合成后，G是一种跨膜蛋白，其羧基末端约30个氨基酸保留在内质网的细胞质侧。由于含有碳水化合物残基的95%的糖蛋白对外部蛋白酶的攻击具有抗性，它似乎在内质网腔中或嵌入脂质双层中。最后，我们表明，在无细胞提取物中可以实现G的合成、糖基化以及将其正确不对称插入内质网。在这个无细胞系统中，G的糖基化和正确插入内质网膜都需要伴随蛋白质合成。
