Osman H, Mazet J L, Maume G, Maume B F
Unité Associée INRA-Université 692, Université de Bourgogne B.P. 400, Dijon, France.
Biochem Biophys Res Commun. 1997 Feb 24;231(3):789-92. doi: 10.1006/bbrc.1997.6183.
The ras-transformed newborn rat adrenocortical (RTAC) cells were obtained by transfection with the mutated c-Ha-rasEJ oncogene. They are proliferative and tumorigenic cells characterized by expression of the c-Ha-rasEJ oncogene and overexpression of a wild-type ras oncogene. The overproduced Ras p21 was identified here as Ki-Ras p21 by western blotting using a specific anti-Ki-Ras monoclonal antibody. Radioactivity derived from [14C]mevalonolactone was strongly incorporated into Ras p21 overproduced in RTAC cells. RTAC cells pretreated with lovastatin and labeled with either [3H]geranylgeranyl-pyrophosphate or [3H]farnesyl-pyrophosphate incorporated also radioactivity into Ras p21. These results showed that overproduced Ras proteins were geranylgeranylated as well as farnesylated in RTAC cells. These findings suggest that the strategy for inhibiting proliferation of Ki-ras-dependent tumorigenic cells should be directed against not only farnesylation but also geranylgeranylation of Ras p21.
通过用突变的c-Ha-rasEJ癌基因转染获得ras转化的新生大鼠肾上腺皮质（RTAC）细胞。它们是增殖性和致瘤性细胞，其特征在于c-Ha-rasEJ癌基因的表达和野生型ras癌基因的过表达。通过使用特异性抗Ki-Ras单克隆抗体的蛋白质印迹法，此处鉴定出过量产生的Ras p21为Ki-Ras p21。源自[14C]甲羟戊酸内酯的放射性被强烈掺入RTAC细胞中过量产生的Ras p21中。用洛伐他汀预处理并用[3H]香叶基香叶基焦磷酸或[3H]法尼基焦磷酸标记的RTAC细胞也将放射性掺入Ras p21中。这些结果表明，过量产生的Ras蛋白在RTAC细胞中既被法尼基化也被香叶基香叶基化。这些发现表明，抑制Ki-ras依赖性致瘤细胞增殖的策略不仅应针对Ras p21的法尼基化，还应针对其香叶基香叶基化。
