Goalstone M, Leitner J W, Draznin B
Medical Research Service, Veterans Affairs Medical Center, Denver, Colorado, USA.
Biochem Biophys Res Commun. 1997 Oct 9;239(1):42-5. doi: 10.1006/bbrc.1997.7413.
Insulin promotes the phosphorylation and activation of farnesyltransferase (FTase) in a time- and a dose-dependent manner. Increased FTase activity results in a larger pool of farnesylated p21Ras and allows for enhanced GTP loading. Insulin significantly increases the pool of farnesylated p21Ras from 20-25% in quiescent 3T3-L1 fibroblasts to approximately 70%, most of which is targeted to the plasma membrane. Furthermore, insulin promotes GTP loading of plasma membrane and not cytosolic p21Ras. The half-life of plasma membrane-associated farnesylated p21Ras is approximately 6 hours, and is identical in control and insulin-treated cells. We have also observed a direct correlation between the amounts of farnesylated p21Ras at the plasma membrane and the magnitude of insulin-induced GTP loading of p21Ras.
胰岛素以时间和剂量依赖的方式促进法尼基转移酶（FTase）的磷酸化和激活。FTase活性增加导致法尼基化的p21Ras池更大，并允许增强的GTP负载。胰岛素显著增加法尼基化的p21Ras池，从静止的3T3-L1成纤维细胞中的20%-25%增加到约70%，其中大部分靶向质膜。此外，胰岛素促进质膜而非胞质p21Ras的GTP负载。质膜相关的法尼基化p21Ras的半衰期约为6小时，在对照细胞和胰岛素处理的细胞中相同。我们还观察到质膜上法尼基化的p21Ras量与胰岛素诱导的p21Ras的GTP负载量之间存在直接相关性。
