Ramos K S, Ou X
Department of Physiology and Pharmacology, College of Veterinary Medicine, Texas A & M University, College Station 77843-4466.
Toxicol Lett. 1994 Aug;73(2):123-33. doi: 10.1016/0378-4274(94)90102-3.
The profile of endogenous protein phosphorylation mediated by protein kinase C (PKC) was examined in cell fractions prepared from subcultured aortic smooth muscle cells (SMCs) isolated from rats treated with 70 mg/kg allylamine (AAM) or tap water for 20 days. Increased phosphorylation of endogenous proteins was observed under unstimulated conditions in the particulate, but not cytosolic, fraction of cells from AAM-treated animals (i.e. AAM cells) relative to control cells. Although the same phosphorylation bands were observed in the particulate or cytosolic fraction of control and AAM cells following phorbol ester stimulation of the enzyme, enhanced PKC-mediated phosphorylation was observed in both fractions of AAM cells relative to control cells. Measurements of exogenous histone Type III-S phosphorylation by PKC following in vitro exposure of naive SMCs to 100 microM AAM for up to 60 min revealed that AAM selectively increased histone phosphorylation in the cytosolic fraction of SMCs. These results demonstrate that AAM treatment enhances PKC-mediated protein phosphorylation in rat aortic SMCs and raise the possibility that such alterations participate in the angiotoxic response to AAM.
在从用70 mg/kg烯丙胺（AAM）或自来水处理20天的大鼠分离的传代培养主动脉平滑肌细胞（SMC）制备的细胞组分中，检测了蛋白激酶C（PKC）介导的内源性蛋白磷酸化情况。与对照细胞相比，在未刺激条件下，AAM处理动物（即AAM细胞）的细胞颗粒部分而非胞质部分观察到内源性蛋白磷酸化增加。尽管在用佛波酯刺激该酶后，对照细胞和AAM细胞的颗粒或胞质部分观察到相同的磷酸化条带，但相对于对照细胞，AAM细胞的两个部分均观察到PKC介导的磷酸化增强。将未处理的SMC体外暴露于100 microM AAM长达60分钟后，通过PKC对外源组蛋白III-S磷酸化的测量表明，AAM选择性增加了SMC胞质部分的组蛋白磷酸化。这些结果表明，AAM处理增强了大鼠主动脉SMC中PKC介导的蛋白磷酸化，并增加了这种改变参与对AAM血管毒性反应的可能性。
