P53 AND P21 WAF PROTEINS MODULATE JNK ACTIVITY

哺乳动物细胞暴露于紫外线(UV)和DNA损伤 毒剂触发紫外线反应，其特征是诱导 细胞周期调控蛋白如P53和细胞周期蛋白 依赖性激酶抑制因子p21WAF。细胞对基因毒性也有反应 Jun氨基末端激酶激活应激/应激激活 蛋白激酶途径(JNK/SAPK)。我们的初步结果表明 野生型P53蛋白和p2lWAF蛋白均可协同作用。 JNK1酶免疫沉淀全细胞提取液。这些 据我们所知，这些结果是第一份报告， P53和p21WAF蛋白均与JNK1酶相关。 手机。此外，我们的研究表明，当细胞表达 野生型P53蛋白和p2lWAF蛋白，基础JNK1活性低， 紫外线对JNK1的诱导作用比对照水平高出许多倍。相比之下， 当细胞表达突变的p53val135蛋白和低水平的 P2lWAF，基础JNK1活性升高，并成倍诱导JNK1 控制上方的紫外线减少。JNK1蛋白Has的进一步分析 为JNK1的磷酸化状态提供了初步证据 在表达野生型p53和p21WAF1蛋白的细胞中发生改变 (不同于通常与JNK1激活相关的基因)。这些 初步结果使我们假设野生型P53蛋白 和p21WAF都与细胞内的JNK1结合，这种相互作用影响 抑制基础JNK1活性的JNK1信号转导 调节JNK1被应激刺激诱导的能力 紫外线照射。我们进一步假设，磷酸化状态 JNK1蛋白的表达受p53/p21WAF依赖机制的调节。 以下具体目标将检验这些假设：目标1 将表征P53蛋白和p21WAF蛋白与 培养细胞中的JNK蛋白。目标2号将调查这一影响 P53/p21WAF蛋白与JNK1酶相互作用对JNK1功能的影响 细胞。目标3将调查 JNK1蛋白在细胞中的磷酸化状态发生改变 P53/p21WAF。目标编号4将描述P53的相互作用 蛋白、p21WAF1蛋白和JNK1蛋白在体内表达。

Exposure of mammalian cells to ultraviolet light (UV) and DNA damaging agents triggers the UV response which is characterized by induction of cell cycle regulatory proteins such as p53 and the cyclin-cyclin dependent kinase inhibitor p21WAF. Cells also respond to genotoxic stress by activation of the Jun amino terminal kinase/stress-activated protein kinase pathway (JNK/SAPK). Our preliminary results demonstrate that both wildtype p53 protein and p2lWAF protein can be co- immuneprecipitated with JNK1 enzyme in whole cell extracts. These results represent, to the best of our knowledge, the first report that both p53 and p21WAF proteins are associated with JNK1 enzyme in the cell. In addition, our studies indicate that when cells are expressing wildtype p53 protein and p2lWAF protein, basal JNK1 activity is low and JNK1 can be induced many-fold by UV above control levels. In contrast when cells are expressing mutant p53val135 protein and low levels of p2lWAF, basal JNK1 activity is elevated and fold induction of JNK1 by UV above control is reduced. Further analysis of JNK1 protein has provided preliminary evidence that the phosphorylation status of JNK1 is altered in cells expressing wildtype P53 and p21WAF1 protein (distinct from that normally associated with JNK1 activation). These preliminary results have led us to hypothesize that wildtype p53 protein and p21WAF both bind to JNK1 in the cell and this interaction affects JNK1 signal transduction by inhibiting basal JNK1 activity and modulating the ability of JNK1 to be induced by stress stimuli such as UV irradiation. We further hypothesize that the phosphorylation status of the JNK1 protein is modulated by a p53/p2lWAF-dependent mechanism. The following specific aims will test these hypotheses: Aim number 1 will characterize the interaction of p53 protein and p21WAF protein with JNK protein in cultured cells. Aim number 2 will investigate the effect of p53/p21WAF protein interaction with JNK1 enzyme on JNK1 function in cells. Aim number 3 will investigate the mechanism by which the phosphorylation status of JNK1 protein is altered in cells expressing p53/p21WAF. Aim number 4 will characterize the interaction of p53 protein, p2lWAFprotein, and JNK1 protein in vivo.