NOTCH SIGNALING IN MAMMALIAN CELLS

描述：Notch/LIN-12/GLP-1跨膜蛋白家族成员 受体被认为在发育中起着重要作用， 无脊椎动物的细胞命运决定 申请人已经分离出几种 来自大鼠的编码Notch受体和Notch配体的基因，并且已经被 研究它们的表达和功能，以解决 哺乳动物发育过程中的Notch信号。 Notch与 恶性肿瘤，这表明了维持一个不确定的状态， 正常发育，Notch也参与人类中风疾病 和痴呆症（CADASIL和阿尔茨海默病），这表明了一个作用以外的 发展也是。 所提出的实验是基于申请人的 以前的调查结果，是逻辑扩展，旨在回答一些 关于Notch函数的基本问题。 他们将决定诺奇 作为二聚体或单体起作用，并且如果Notch的配体活化涉及 配体二聚化。 他们还将探索Notch细胞表面 表达受到调控，并研究Notch被切割的假设 并在配体结合后转运至细胞核。 相比 无脊椎动物系统的报告， 令人惊讶的观察是，哺乳动物配体在它们的 激活不同Notch受体的能力。 基于这些 观察，他们设计了实验来识别存在的序列 在配体和受体中， 的特异性 此外，他们还将探索生产和使用 可溶形式的Notch配体以研究Notch信号传导。 他们发现 Notch信号传导导致CBF1依赖性和 CBF1非依赖性通路。 初步数据显示， CBF1依赖性通路正调控Notch的表达。 他们 将研究这种正反馈背后的分子机制 系统 他们还将研究相互信号传导的可能性， 配体-受体相互作用后的配体表达细胞。 一起 这项资助中提出的实验将提供有关 Notch-配体相互作用的结构/功能要求， 扩展了我们目前对哺乳动物Notch信号的理解。

DESCRIPTION: Members of the Notch/LIN-12/GLP-1 family of transmembrane receptors are believed to play a central role in development by regulating cell-fate decisions in invertebrates. The applicant has isolated several genes encoding Notch receptors and Notch ligands from rat, and has been studying their expression and function to address the molecular mechanism of Notch signaling during mammalian development. Notch is associated with malignancies, suggesting a role for maintaining an undetermined state during normal development, and Notch is also involved in human disorders of stroke and dementia (CADASIL and Alzheimer's disease), suggesting a role outside of development as well. Experiments proposed are based on the applicant's previous findings, and are logical extensions designed to answer a number of basic questions concerning Notch function. They will determine if Notch functions as a dimer or monomer, and if ligand activation of Notch involves ligand dimerization. They also will explore how Notch cell surface expression is regulated and investigate the hypothesis that Notch is cleaved and transported to the nucleus following ligand binding. In contrast to what has been reported for the invertebrate systems, they made the surprising observation that the mammalian ligands are not equal in their ability to activate the different Notch receptors. Based on these observations, they have designed experiments to identify sequences present in the ligands and receptors that account for the observed ligand specificity. In addition, they will explore the production and use of soluble forms of Notch ligands to study Notch signaling. They found that Notch signaling leads to activation of both CBF1-dependent and CBF1-independent pathways. Preliminary data indicate that the CBF1-dependent pathway positively regulates the expression of Notch. They will investigate the molecular mechanisms underlying this positive feedback system. They will also examine the possibility of reciprocal signaling in the ligand-expressing cell following ligand-receptor interactions. Together the experiments proposed in this grant will provide new information on the structure/function requirements of Notch-ligand interactions and thereby extend our present understanding of mammalian Notch signaling.