Crise B, Ruusala A, Zagouras P, Shaw A, Rose J K
Department of Pathology, School of Medicine, Yale University, New Haven, Connecticut 06510-8023.
J Virol. 1989 Dec;63(12):5328-33. doi: 10.1128/JVI.63.12.5328-5333.1989.
The vesicular stomatitis virus glycoprotein forms noncovalently linked trimers in the endoplasmic reticulum before being transported to the Golgi apparatus. The experiments reported here were designed to determine if the extracellular domain of the glycoprotein contains structural information sufficient to direct trimer formation. To accomplish this, we generated a construct encoding G protein with the normal transmembrane and anchor sequences replaced with the sequence encoding 53 C-terminal amino acids from the Thy-1.1 glycoprotein. We show here that these sequences were able to specify glycolipid addition to the truncated G protein, probably after cleavage of 31 amino acids derived from Thy-1.1. The glycolipid-anchored G protein formed trimers and was expressed on the cell surface in a form that could be cleaved by phosphoinositol-specific phospholipase C. However, the rate of transport was reduced, compared with that of wild-type G protein. A second form of the G protein was generated by deletion of only the transmembrane and cytoplasmic domains. This mutant protein also formed trimers with relatively high efficiency and was secreted slowly from cells.
水泡性口炎病毒糖蛋白在内质网中形成非共价连接的三聚体，然后被转运至高尔基体。本文报道的实验旨在确定糖蛋白的胞外结构域是否包含足以指导三聚体形成的结构信息。为实现这一目的，我们构建了一个编码G蛋白的基因，将其正常的跨膜和锚定序列替换为来自Thy-1.1糖蛋白的53个C末端氨基酸的编码序列。我们在此表明，这些序列能够指定糖脂添加到截短的G蛋白上，可能是在源自Thy-1.1的31个氨基酸被切割之后。糖脂锚定的G蛋白形成三聚体，并以可被磷酸肌醇特异性磷脂酶C切割的形式表达在细胞表面。然而，与野生型G蛋白相比，其转运速率降低。通过仅缺失跨膜和胞质结构域产生了G蛋白的第二种形式。这种突变蛋白也以相对较高的效率形成三聚体，并从细胞中缓慢分泌。
