MORPHOGENIC SIGNAL TRANSDUCTION IN NEURONS

描述：(改编自申请者摘要) 发育神经科学通过以下途径控制神经细胞分化 形态发生信号。神经元如何转导一类神经的最新线索 与整合素功能相关的形态发生信号来自于 该小组对阿尔茨海默氏症发病机制的分子水平研究。在……里面 测试淀粉样蛋白诱发的细胞死亡可能涉及异常蛋白的想法 酪氨酸磷酸化，人们发现发育中的神经元表达 高水平的新型非受体蛋白酪氨酸激酶，称为局灶性 黏附蛋白激酶(FAK)。在非神经细胞中，FAK受整合素的调节 活性，第一个显示这种转导联系的特定激酶；FAK 此外，它是控制肌动蛋白的分子机制的一部分 组织。因此，FAK发挥重要作用具有很强的先例 在整合素依赖的形态发生信号转导中的作用，并可能对 其他形态发生的信号通路也是如此。初步数据充分支持 这种可能性：FAK在大脑中表达，它的酪氨酸磷酸化 极大地下调了发展，它与 神经突起和生长锥体中的纽蛋白，并形成内源性复合体 对于Fyn，另一种与轴突生长有关的非受体酪氨酸激酶。 提出了三个目标：(1)表征FAK浓度的变化， 大鼠脑细胞发育过程中酪氨酸磷酸化及其分布 在体内和在培养中，测试预测的相关性与一个家庭 肌动蛋白组织蛋白。(2)测试FAK击倒对 形态发生行为和结构，使用粘附性分析，轴突 伸展、生长锥运动和神经源性细胞构筑。(3) 识别信号依赖的神经元FAK复合体，比较 生物化学分离的复合体与在粘连基因座上鉴定的那些 免疫金标全片电子显微镜原位观察。数据将成为 神经元FAK的发育、功能和机制的关键问题 行动，检验FAK，与家庭一起发挥作用的假设 肌动蛋白组织蛋白，是一种转导因子 神经元细胞构筑控制的形态发生信号 细胞骨架。

DESCRIPTION: (adapted from Applicant's Abstract) A central issue in developmental neuroscience is the control of nerve cell differentiation by morphogenic signals. A recent clue into how neurons may transduce one class of morphogenic signals, associated with integrin function, has come from this group's molecular-level studies of Alzheimer's pathogenesis. In testing the idea that amyloid-evoked cell death may involve aberrant protein tyrosine phosphorylations, it was discovered that developing neurons express high levels of the novel nonreceptor protein tyrosine kinase known as focal adhesion kinase (FAK). In non-neuronal cells, FAK is regulated by integrin activity, the first specific kinase to show this transductional linkage; FAK moreover is part of the molecular machinery that controls actin organization. Strong precedent thus exists for FAK to play an important role in integrin-dependent morphogenic signal transduction, and possibly for other morphogenic signal pathways as well. Preliminary data amply support this possibility: FAK is expressed in brain, its tyrosine phosphorylation drastically down-regulates with development, it colocalizes with clusters of vinculin in neurites and growth cones, and it forms an endogenous complex with Fyn, another nonreceptor tyrosine kinase implicated in axon outgrowth. Three aims are proposed: (1) Characterize changes in FAK concentration, tyrosine phosphorylation and distribution for rat brain cells developing in vivo and in culture, testing for predicted correlations with a family of actin-organizing proteins. (2) Test the impact of FAK knockdown on morphogenic behavior and structure, using assays for adhesion, neurite extension, growth cone movements, and neuritogenic cytoarchitecture. (3) Identify signal-dependent neuronal FAK complexes, comparing biochemically-isolated complexes with those identified at adhesive loci in situ by immunogold whole mount electron microscopy. Data will characterize critical aspects of neuronal FAK development, function and mechanisms of action, testing the hypothesis that FAK, functioning in tandem with a family of actin-organizing proteins, is a transduction factor that couples morphogenic signals to cytoarchitectural control of the neuronal cytoskeleton.