CELLULAR FUNCTIONS OF ALZHEIMER'S DISEASE PROTEINS

描述(改编自申请)：基因证据表明 三种蛋白质，β-淀粉样前体蛋白(β-APP)和两种 同源早老素(PS-1和PS-2)在阿尔茨海默病病因中的作用 (Ad)。调查员此前曾根据其他案件的先例提出 发育系统，即一种或多种形式的beta-app和PS-1(或PS-2) 可能是正常生理中细胞间信号系统的组成部分。 β-APP与相邻细胞表面的PS-1或PS-2结合 特别是通过它们的胞外结构域相互作用 细胞表面形成薄膜，并产生信号。β-淀粉样蛋白(Abeta) 蛋白水解物这种相互作用后的其他事件的蛋白分解副产物这个 目前的建议是基于国际和平研究所和同事们为 这一建议的Beta-APP：PS介导的细胞间信号事件。文化修养 瞬时转染β-APP、PS-1或PS-2的细胞 适当混合，并分析蛋白质酪氨酸激酶活性， 对于净蛋白酪氨酸磷酸化，用特异性抗体 磷酸酪氨酸(Ptyr)。在混合测试版应用后的几分钟内 用PS-1或PS-2转染的细胞，细胞 提取物显示蛋白酪氨酸激酶显著增加。 活性，以及在蛋白质底物的Ptyr修饰中，没有出现 在控件中。此外，酪氨酸修饰蛋白质的光谱 磷酸化的不同取决于PS-1或PS-2是否参与了 与β-APP的特异性细胞间结合，暗示PS-1和PS-2 在正常生理中有明显的功能，而不是多余的功能。这个 具体目标是研究β-APP和BAPP之间的细胞间相互作用 PS，决定信号的方向，识别非受体 酪氨酸激酶的中介作用，并表征src激酶在 这一过程。

DESCRIPTION (adapted from the application): Genetic evidence has implicated three proteins, the beta-amyloid precursor protein (beta-APP) and the two homologous presenilins (PS-1 and PS-2), in the etiology of Alzheimer's disease (AD). The investigator had previously proposed based on precedents in other developmental systems, that one or more forms of beta-APP and PS-1 (or PS-2) may be components of an intercellular signaling system in normal physiology. beta-APP and PS-1 or PS-2 on the surfaces of neighboring cells would bind to one another specifically through their extra-cellular domains protruding from the cell surface membranes and generate a signal. beta-amyloid (Abeta) would be a proteolytic by-product of other events following this interaction. The present proposal is based on evidence that the PI and colleagues have shown for this proposed beta-APP: PS-mediated intercellular signaling event. Cultured cells, transiently transfected with either beta-APP, PS-1 or PS-2, were appropriately mixed, and were analyzed for protein tyrosine kinase activity, and for net protein tyrosine phosphorylation, with antibodies specific for phosphotyrosine (Ptyr). Within several minutes after mixing the beta-APP transfected cells with either the PS-1 or PS-2 transfected cells, the cell extracts showed significant transient increases in protein tyrosine kinase activity, and in Ptyr modification of protein substrates, that did not appear in controls. Furthermore, the spectrum of proteins modified by tyrosine phosphorylation differs depending on whether PS-1 or PS-2 is involved in the specific intercellular binding to beta-APP, which implies that PS-1 and PS-2 have distinct, rather than redundant, functions in normal physiology. The specific aims are to study the intercellular interactions between beta-APP and the PS, to determine the direction of signal, to identify the non-receptor tyrosine kinases that mediate it and to characterize the role of src kinases in the process.