Understanding the Role of kB Ras Proteins in Signaling and Development

描述（由申请人提供）：该项目的目标是了解(B- ras1和（B- ras2）是如何调控的，(B- ras1和（B- ras2）是ras样蛋白的一个不寻常亚类的成员，以及它们如何反过来调控导致NF-(B)和Ral gtpase的途径。这些蛋白最初是通过它们与I(B)蛋白的物理相互作用发现的，体外和过表达实验表明它们是NF-(B)的抑制剂。然而，这些蛋白质真正的生理作用仍不清楚。我们通过敲除两个B-ras基因的初步结果表明，它们可以抑制NF- B和Ral GTPase途径。有趣的是，缺乏B-Ras蛋白的小鼠也会因肺部发育缺陷而在围产期死亡。在这个研究计划中，我们的目标是提出以下问题。在Aim 1中，我们将研究B- ras实际上是如何调节NF- B的。虽然影响I(B)的稳定性可能是一种机制，但关于B- ras究竟如何起作用的许多问题仍未得到解答。缺乏B-Ras细胞的可用性将使我们能够以系统的方式探索潜在的机制。我们还将使用巨噬细胞中缺乏B-Ras的小鼠来研究包括感染性休克和胶原诱导关节炎在内的炎症小鼠模型。在Aim 2中，我们将探讨B- ras如何调节Ral，并确定活化的Ral是否有助于NF- B的活化。我们将研究生长因子信号通路破坏B-Ras-RalGAP复合物的机制，并确定与B-Ras结合抑制RalGAP活性的原因。我们还将测试B- ras缺陷细胞中活化的Ral是否有助于NF- B活化。最后，在Aim 3中，我们将探讨在b - ras缺陷动物中观察到的肺表型。我们将研究表面活性剂表达失调的机制，特别是NF- B在这一过程中的作用。总之，这些研究将为这些进化上保守但神秘的ras样蛋白质家族成员的生物学提供重要的新见解。

DESCRIPTION (provided by applicant): The goal of this project is to understand how (B-Ras1 and (B-Ras2, members of an unusual sub-class of Ras-like proteins, are regulated, and how they in turn regulate pathways leading to NF-(B and Ral GTPases. These proteins were originally discovered through their physical interaction with the I(B( protein, and in vitro and overexpression experiments indicated that they are inhibitors of NF-(B. However the true physiological role of these proteins has remained unclear. Our preliminary results using knock-outs of both (B-ras genes shows that they act to inhibit both NF-(B and Ral GTPase pathways. Interestingly, mice lacking (B-Ras proteins also die perinatally due to defects in lung development. In this research proposal we aim to ask the following questions. In Aim 1 we will study how (B-Ras actually regulates NF-(B. While affecting the stability of I(B( is a likely mechanism, many questions about exactly how (B-Ras functions remains unanswered. Availability of cells lacking (B-Ras will allow us to explore the underlying mechanism in a systematic manner. We will also use mice lacking (B-Ras in macrophages to study mouse models of inflammation including septic shock and collagen-induced arthritis. In Aim 2 we will ask how (B-Ras regulates Ral, and determine whether activated Ral contributes to NF-(B activation. We will study the mechanism by which growth factor signaling disrupts the (B-Ras-RalGAP complex, and determine why binding to (B-Ras inhibits the activity of RalGAP. We will also test whether the activated Ral in (B-Ras deficient cells contributes to NF-(B activation. Finally in Aim 3 we will explore the lung phenotype seen in the (B-Ras-deficient animals. We will study the mechanism of dysregulated surfactant expression, in particular the role of NF-(B in the process. In summary these studies will provide significant new insight into the biology of these evolutionarily conserved, yet enigmatic, members of this Ras-like family of proteins.