Regulation of the MAP Kinase Pathway in Senescence

描述(申请人提供)：复制性衰老的特征是 由众多细胞过程的普遍失调所致。然而， 体外衰老细胞的特征是不能通过DNA对有丝分裂原做出反应 合成和细胞分裂。我们之前的研究表明， 增殖性反应主要基于信号失灵和这些 发生在受体结合的下游。MAP激酶途径就是该途径 大多数与有丝分裂反应有关。我们已经检查了丰富度 以及这一途径中各种中间体的活性。尽管有 有丝分裂原的某些变化刺激青年和青年之间ERK活性的增加 当按每毫克蛋白质计算时，衰老细胞的活性是 一样的。衰老过程中最戏剧性的变化是 P-ERK在衰老细胞的胞核中表达。这与失败是一致的 衰老细胞对p-ERK的磷酸化？S靶点，ELK-1。 本项目中提出的实验将解决失败的机制 核内p-ERK易位。我们将研究p-ERK的二聚化是否 需要运输的，在老化中是有缺陷的。我们将研究 年轻和衰老细胞胞核中的磷酸酶活性。我们会 确定是否加速了p-ERK从细胞核的输出 衰老细胞中是否存在核锚(S)失效。在……里面 此外，我们将确定在衰老患者中恢复p-ERK的后果。 细胞，最后我们将使用SV40T抗原作为探针的机制 核内p-ERK的大分子组装的基础。我们的目标是 了解MAP激酶丝裂原信号失活的机制 培养中的转导作为衰老过程中信号失灵的模型。

DESCRIPTION (provided by applicant): Replicative senescence is characterized by a general dysregulation of numerous cellular processes. However, the hallmark of senescent cells in vitro is failure to respond to mitogens by DNA synthesis and cell division. Our previous studies have shown that failure of the proliferative response is based primarily in signaling failures and these occur downstream of receptor binding. The MAP Kinase pathway is the pathway most associated with the mitogenic response. We have examined the abundance and activity of various intermediates in this pathway. Although there were some changes in mitogen stimulated increases in ERK activity between young and senescent cells, when calculated per mg of protein, the activities were the same. The most dramatic change in senescence was the much reduced abundance of p-ERK in the nucleus of senescent cells. This was consistent with the failure of senescent cells to phosphorylate p-ERK?s target, Elk-1. The experiments proposed in this project will address the mechanism of failed translocation of nuclear p-ERK. We will examine whether dimerization of p-ERK required for transport, is defective in senescence. We will examine phosphatase activity in the nucleus of young and senescent cells. We will determine whether there is accelerated export of p-ERK from the nucleus and whether there is failure of a nuclear anchor(s) in senescent cells. In addition, ?we will determine the consequences of restoring p-ERK in senescent cells and finally we will use SV40 T antigen as a probe of the mechanisms underlying the macromolecular assembly of nuclear p-ERK. Our goal is to understand the mechanisms underlying the failure in MAP Kinase mitogen signal transduction in culture as a model for signaling failures in aging.