Price B D, Morris J D, Marshall C J, Hall A
Institute of Cancer Research, Chester Beatty Laboratories, London, U.K.
Biochem J. 1989 May 15;260(1):157-61. doi: 10.1042/bj2600157.
The effect of scrape-loaded [Val-12]p21ras on agonist-stimulated phosphatidylinositol 4,5-bisphosphate (PIP2) turnover in Swiss-3T3 cells was studied. Previously [Morris, Price, Lloyd, Marshall & Hall (1989) Oncogene 4, 27-31] we demonstrated that [Val-12]p21ras activates protein kinase C within 10 min of scrape loading. Here, we show that [Val-12]p21ras inhibits bombesin and platelet-derived growth factor-stimulated PIP2 breakdown 1.5-4 h after scrape loading. This effect persisted for at least 18 h and could be mimicked in control cells by activation of protein kinase C with 12-O-tetradecanoyl 13-acetate (TPA) 15 min prior to ligand stimulation. When protein kinase C was down-regulated by chronic TPA treatment, [Val-12]p21ras was no longer able to inhibit agonist-stimulated inositol phosphate production. These results indicate that changes in inositol phosphate levels caused by ras protein are probably due to activation of protein kinase C and not to an interaction of ras with phospholipase C.
研究了刮擦加载的[Val-12]p21ras对瑞士3T3细胞中激动剂刺激的磷脂酰肌醇4,5-二磷酸（PIP2）周转的影响。此前[莫里斯、普赖斯、劳埃德、马歇尔和霍尔（1989年）《癌基因》4，27 - 31]我们证明，[Val-12]p21ras在刮擦加载后10分钟内激活蛋白激酶C。在此，我们表明，[Val-12]p21ras在刮擦加载后1.5 - 4小时抑制蛙皮素和血小板衍生生长因子刺激的PIP2分解。这种作用持续至少18小时，并且在配体刺激前15分钟用12 - O - 十四烷酰佛波醇-13-乙酸酯（TPA）激活蛋白激酶C可在对照细胞中模拟这种作用。当通过长期TPA处理下调蛋白激酶C时，[Val-12]p21ras不再能够抑制激动剂刺激的肌醇磷酸生成。这些结果表明，ras蛋白引起的肌醇磷酸水平变化可能是由于蛋白激酶C的激活，而不是ras与磷脂酶C的相互作用。
