EFFECTORS AND REGULATORS OF NORMAL AND ONCOGENIC RAS

描述：(改编自研究人员的摘要)RAS蛋白起作用 作为细胞对外部信号反应的关键控制元件。 某些质膜受体的刺激可导致细胞的激活 RAS和促有丝分裂反应。突变的、构成活性的RAS形式 可导致不依赖于受体的持续有丝分裂信号 刺激。这类RAS突变是最常见的致病事件之一 在人类肿瘤中。然而，在某些特定的哺乳动物细胞类型中，RAS 激活导致细胞周期停滞和分化。这表明 这种细胞类型的差异为解释RAS提供了一个背景 可能导致细胞周期进展或停滞的信号和 差异化。 直接连接RAS激活和基因变化的一条下游途径 细胞分裂所需的表达已经被发现。钥匙 第一步是蛋白激酶Raf1的激活。这是由一个 RAF1和RAS之间的物理相互作用。然而，还有其他 RAS中介的事件似乎是完全转换所必需的，或者 分化反应，提示参与了额外的RAS 互动伙伴。他们已经分离并继续研究Rin1， 一种能与激活的RAS特异结合并能竞争的人类蛋白质 与Raf1在一起。Rin 1和Raf1的行为还有其他相似之处， 包括它们与14-3-3蛋白的相互作用。 Rin1的组织类型表达受到广泛的调控。此外, Rin1的一些剪接变体形式改变了属性。他们的发现 与Rin1一致，作为受调控的RAS效应器，作为Raf1 竞争对手或两者兼而有之。有趣的是，RIN1基因已经被定位到 11q13.2，一个在鳞状细胞中经常被扩增的染色体位置 细胞癌和乳腺肿瘤。 该提案包括对Rin1结合特性和功能的分析。 重点放在哺乳动物细胞中的相互作用上。 (共免疫沉淀和共免疫荧光)和关于生物 这些相互作用的后果(对RAS介导的转换的影响 和差异化)。他们将利用人工和 自然产生的具有不同结合特性的Rin1变体。 这些研究针对Rin1功能在RAS介导的信号中的作用 转导，应该有助于他们对正常细胞的理解 包括分化和有丝分裂以及癌症的过程 病理学。

DESCRIPTION: (adapted from the investigator's abstract) Ras proteins serve as critical control elements in the response of cells to external signals. The stimulation of some plasma membrane receptors can lead to activation of Ras and a mitogenic response. Mutant, constitutively active, forms of Ras can lead to a persistent mitotic signal that is independent of receptor stimulation. Such Ras mutations are among the most common causative events in human tumors. In some specialized mammalian cell types, however, Ras activation leads to cell cycle arrest and differentiation. This suggests that cell type differences provide a context for the interpretation of Ras signals which may lead to either cell cycle progression or arrest and differentiation. One downstream pathway directly connecting Ras activation to changes in gene expression that are required for cell division has been uncovered. The key first step is activation of the protein kinase Raf1. This is initiated by a physical interaction between Raf1 and Ras. There are however, other Ras-mediated events that appear to be required for a full transformation or differentiation response, suggesting the involvement of additional Ras interaction partners. They have isolated and are continuing to study Rin1, a human protein that binds specifically to activated Ras and can compete with Raf1. There are additional parallels between Rin 1 and Raf1 behavior, including their interactions with 14-3-3 proteins. Tissue type expression of Rin1 is regulated over a wide range. In addition, some splice variant forms of Rin1 have altered properties. Their findings are consistent with Rin1 functioning as a regulated Ras effector, as a Raf1 competitor or as both. Interestingly, the rin 1 gene has been mapped to 11q13.2, a chromosomal position that is frequently amplified in squamous cell carcinomas and breast tumors. This proposal includes an analysis of Rin1 binding properties and function. The focus is on interactions that occur in mammalian cells (co-immunoprecipitations and co-immunofluorescence) and on the biological consequences of those interactions (effects on Ras-mediated transformation and differentiation). They will take advantage of both artificial and naturally occurring variants of Rin1 that have different binding properties. These studies, directed at the role of Rin1 function in Ras-mediated signal transduction, should facilitate their understanding of normal cellular processes including differentiation and mitosis as well as cancer pathologies.