Matsuoka Y, Chen S Y, Holland C E, Compans R W
Department of Microbiology and Immunology, Emory University, Atlanta, Georgia 30322, USA.
Arch Biochem Biophys. 1996 Dec 1;336(1):184-9. doi: 10.1006/abbi.1996.0547.
The G1 glycoprotein of Punta Toro virus, a member of the bunyavirus family, accumulates in the Golgi complex when it is expressed from cloned cDNA. We previously reported that the information necessary for Golgi retention of the G1 protein is located within the transmembrane domain and a portion of the cytoplasmic domain adjacent to the transmembrane domain (Matsuoka, Y., Chen, S.-Y., and Compans, R. W. (1994) J. Biol. Chem. 269, 22565-22573). To determine the features of the amino acid sequence motif required for Golgi retention, we have introduced mutations including truncations and point mutations in the transmembrane and the cytoplasmic domains and examined the cellular localization of the expressed mutant proteins. The results from truncation mutants indicate that the crucial information appears to be located within the first 10 amino acids of the cytoplasmic domain. Within this region, mutation of a proline residue yielded a protein that was transported to the cell surface. A protein was also expressed on the cell surface when one of the threonine residues in the transmembrane domain was changed to leucine. Thus the transmembrane domain may have a supportive role in Golgi retention, possibly by promoting protein interactions through hydroxylated side chains.
蓬塔托罗病毒（布尼亚病毒科成员）的G1糖蛋白在通过克隆cDNA表达时会在高尔基体复合体中积累。我们之前报道过，G1蛋白在高尔基体滞留所需的信息位于跨膜结构域以及与跨膜结构域相邻的部分胞质结构域内（松冈洋、陈淑媛和康潘斯·R·W.（1994年）《生物化学杂志》269卷，22565 - 22573页）。为了确定高尔基体滞留所需的氨基酸序列基序的特征，我们在跨膜结构域和胞质结构域中引入了包括截短和点突变在内的突变，并检测了所表达突变蛋白的细胞定位。截短突变体的结果表明，关键信息似乎位于胞质结构域的前10个氨基酸内。在该区域内，脯氨酸残基的突变产生了一种转运至细胞表面的蛋白。当跨膜结构域中的一个苏氨酸残基变为亮氨酸时，一种蛋白也在细胞表面表达。因此，跨膜结构域可能在高尔基体滞留中起支持作用，可能是通过羟基化侧链促进蛋白相互作用。
