CROSSTALK BETWEEN CAMP AND RAS IN ENDOCRINE CELLS

描述(摘自申请人的摘要) 因为单元响应在单元处接收到的广泛的信号阵列 表面上，他们整合和适当应对这些问题的能力 信号是必不可少的。研究得最好的信号传递的例子之一 串扰是RAS和cAMP介导的通路之间的相互作用。循环 AMP抑制许多细胞的增殖，部分是通过解偶联RAS 来自其下游效应器之一的Raf-1。然而，营地的海拔， 并不是所有人都能抑制生长。在甲状腺细胞、垂体腺 促生长激素和其他细胞，cAMP刺激增殖。我们发现 促甲状腺激素(TSH)通过一种新的途径刺激增殖 同时涉及RAS和cAMP依赖的蛋白激酶，但不是Well Ras、Raf-1和丝裂原激活的下游效应因子的研究进展 蛋白激酶级联。促甲状腺激素存在时RAS使用的效应器 CAMP水平升高仍有待阐明，但可能包括 磷脂酰肌醇3-激酶，蛋白激酶C的亚型，以及其他 小G蛋白。 这些研究的目标是阐明那些转导的分子 促甲状腺激素刺激的有丝分裂信号，包括新的RAS的鉴定 效应器，以及RAS和cAMP介导的相互作用部位 小路。使用微量注射纯化的信号分子，并高度 特定的抑制剂，一组RAS突变体的生物活性 各种效应器相互作用中的缺陷将被评估。 过度表达RAS的甲状腺细胞将被筛选出新的蛋白质 绑定到GTP绑定的RAS。其他被认为具有RAS效应器功能的分子 将被评估为甲状腺细胞的生长刺激活性。同舟共济 这些方法将提供对RAS介导的新信号的洞察 甲状腺细胞中活跃的通路。一旦确定了这些分子，我们就 将在其他上皮细胞中测试它们刺激生长的活性， 包括垂体生长激素细胞和乳腺上皮细胞。RAS基因 CAMP介导的信号通路的激活和本质性激活 已经在人类甲状腺癌和脑垂体癌中发现了通路。这个 阐明这些物质的分子组成及其相互作用 通路可能为治疗干预确定新的靶点。 我的长期职业目标是确定分子组成 多种上皮细胞类型中的生长信号通路 具有挑战性的学术环境。宾夕法尼亚大学提供 一个令人兴奋和丰富的研究环境，在其中进行这些研究。

DESCRIPTION (Taken from the applicant's abstract) Because cells respond to a wide array of signals received at the cell surface, their ability to integrate and respond appropriately to these signals is essential. One of the best studied examples of signaling crosstalk is the interplay between Ras- and cAMP-mediated pathways. Cyclic AMP inhibits proliferation in many cells, in part through uncoupling Ras from one of its downstream effectors, Raf-1. Elevations in cAMP, however, are not universally growth inhibitory. In thyrocytes, pituitary somatotrophs and other cells, cAMP stimulates proliferation. We discovered that thyrotropin (TSH) stimulates proliferation through a novel pathway involving both Ras and the cAMP-dependent protein kinase, but not the well described downstream effectors of Ras, Raf-1 and the mitogen-activated protein kinase cascade. The effectors used by Ras in the presence of TSH and elevated cAMP levels remain to be elucidated, but may include phosphatidylinositol 3-kinase, the isoform of protein kinase C, and other small G proteins. It is the goal of these studies to elucidate those molecules which transduce TSH-stimulated mitogenic signals, including the identification of novel Ras effectors, and the sites of interaction between Ras- and cAMP-mediated pathways. Using microinjection of purified signaling molecules and highly specific inhibitors, the biological activity of a panel of Ras mutants defective in various effector interactions will be assessed. Ras-overexpressing thyroid cells will be screened for novel proteins that bind to GTP-bound Ras. Other molecules proposed to function as Ras effectors will be assessed for growth-stimulating activity in the thyrocyte. Together these approaches will provide insight into novel Ras-mediated signaling pathways active in thyroid cells. Once these molecules are identified, we will test their activity in growth stimulation in other epithelial cells, including pituitary somatotrophs and mammary epithelial cells. Ras gene activation and the constitutive activation of cAMP-mediated signaling pathways have been identified in human thyroid and pituitary cancer. The elucidation of the molecular components of, and interactions between these pathways may identify novel targets for therapeutic intervention. My long term career goal is to identify the molecular components of growth-signaling pathways in a variety of epithelial cell types in a challenging academic environment. The University of Pennsylvania provides an exciting and rich research environment in which to pursue these studies.