Bamezai A, Rock K L
Harvard Medical School, Department of Pathology, Boston, Massachusetts.
Oncogene. 1991 Aug;6(8):1445-51.
NIH3T3 cells were transfected with a vector containing c-H-ras under the transcriptional control of the mouse metallothionein-I promoter. When c-H-ras expression was induced with heavy metal ions there was a marked reduction in the expression of two glycosylphosphatidylinositol (GPI) anchored proteins, TAP/Ly-6A.2 and Thy-1, on the plasma membrane of the transformed cells. In contrast the cell-surface expression of other non-GPI-anchored proteins was unaltered. The major loss of Thy-1 induced by ras activation occurred from the pool of molecules expressed on the cell surface. The Thy-1 molecules that were preferentially lost from the surface of the ras-transformed cells could not be recovered from the extracellular fluid by immunoprecipitation. In contrast, the rate of internalization of Thy-1 was increased approximately 69% subsequent to ras activation. The possible significance of these findings to the function of c-H-ras is discussed.
用含有在小鼠金属硫蛋白-I启动子转录控制下的c-H-ras的载体转染NIH3T3细胞。当用重金属离子诱导c-H-ras表达时，转化细胞的质膜上两种糖基磷脂酰肌醇（GPI）锚定蛋白TAP/Ly-6A.2和Thy-1的表达明显降低。相比之下，其他非GPI锚定蛋白的细胞表面表达未改变。ras激活诱导的Thy-1的主要损失发生在细胞表面表达的分子池中。从ras转化细胞表面优先丢失的Thy-1分子不能通过免疫沉淀从细胞外液中回收。相反，ras激活后Thy-1的内化速率增加了约69%。讨论了这些发现对c-H-ras功能的可能意义。
