Pääbo S, Bhat B M, Wold W S, Peterson P A
Cell. 1987 Jul 17;50(2):311-7. doi: 10.1016/0092-8674(87)90226-1.
The E19 protein of adenoviruses is a transmembrane protein that abrogates the intracellular transport of class I antigens by forming complexes with them in the ER. We show here that the E19 protein is retained in the ER even in the absence of class I antigens. To define the region conferring residency in the ER, we examined two mutant forms of the viral protein. A 5 amino acid extension of the 15-membered cytoplasmic tail of the protein reduces its interaction with class I antigens but does not change its intracellular distribution. Shortening the tail to 7 amino acids also diminishes the affinity for class I antigens; however, this mutant E19 protein becomes transported to the cell surface. Thus, we concluded that a small stretch of amino acids exposed on the cytoplasmic side of the ER membrane is responsible for the retention of the E19 protein in the ER.
腺病毒的E19蛋白是一种跨膜蛋白，它通过在内质网（ER）中与I类抗原形成复合物来消除其细胞内运输。我们在此表明，即使在没有I类抗原的情况下，E19蛋白也保留在内质网中。为了确定赋予内质网驻留性的区域，我们检查了病毒蛋白的两种突变形式。该蛋白15个氨基酸的胞质尾端有一个5氨基酸的延伸，这降低了它与I类抗原的相互作用，但没有改变其细胞内分布。将尾端缩短至7个氨基酸也会降低对I类抗原的亲和力；然而，这种突变的E19蛋白会被转运到细胞表面。因此，我们得出结论，内质网膜胞质侧暴露的一小段氨基酸负责E19蛋白在内质网中的保留。
