PI 3-KINASE AND KIT RECEPTOR SIGNALING

本提案的总体目标是研究PI 3的作用- 在体内和体外c-kit受体介导的过程中的激酶。 原癌基因c-kit编码受体酪氨酸激酶（RTK） 它属于一个受体家族，包括血小板- 衍生生长因子（PDGF）。 c-kit受体的配体， 命名为KL，编码一种细胞表面分子， 加工以产生可溶性产品。 而c-kit基因 与小鼠中的白色斑点位点（W）、试剂盒配体（KL）等位 与小鼠的steel基因座（S1）是等位基因。 W和Sl突变 影响造血的各个方面，包括干细胞 隔室，配子发生在胚胎发育和 成年动物，引起大红细胞性贫血，肥大细胞缺乏 贫血、肥大细胞缺乏症、斑点、男性和女性不育症， 巨结肠 基于突变表型，由c- Kit受体非常多样，包括：细胞增殖，细胞 存活，细胞粘附，细胞迁移，介质分泌，细胞 分化和其他有丝分裂后功能。 的说明， 这些不同反应的机制是至关重要的。 类似于其他RTK的工具包调解其行动，通过各种 包括PI 3-激酶在内的细胞质信号转导子在KIT介导的 BMMC与纤连蛋白基质的粘附和IgE的增强 介导的BMMC分泌。 研究Kit/PI 3-激酶介导的 在其他细胞系统中，我们将修改c-kit基因， 突变Kit受体中的PI 3-激酶结合位点， 使用基于cre-lox的策略， 突变 然后，我们将研究突变对各种 W和SI突变的靶点，造血细胞的动力学 种群及其在需要细胞粘附的情况下的行为 和迁移，即归巢到骨髓室， 将干细胞动员到外周。 我们还将修改 酪氨酸残基在膜区域的试剂盒受体， ES细胞影响KL介导的细胞增殖，但不影响KL介导的细胞增殖。 抑制细胞凋亡并研究其后果 体内突变 最后，我们将探讨Kit的作用机制 介导的抑制辐射和因子剥夺诱导的 肥大细胞凋亡。

The overall objectives of this proposal is to investigate the role of PI 3- kinase in c-kit receptor mediated processes in vivo and in vitro. The proto-oncogene c-kit, encodes a receptor tyrosine kinase (RTK) which belongs to a family of receptors that includes the platelet- derived growth factor (PDGF). The ligand of the c-kit receptor, designated KL, encodes a cell surface molecule which may be processed to produce a soluble product. Whereas the c-kit gene is allelic with the white spotting locus (W) in the mouse, kit-ligand (KL) is allelic with the steel locus (Sl) in the mouse. W and Sl mutations affect various aspects of hematopoiesis, including the stem cell compartment, gametogenesis during embryonic development and in the adult animal, causing macrocytic anemia, mast cell deficiency anemia, mast cell deficiency, spotting, male and female sterility and megacolon. Based on mutant phenotypes the cellular responses mediated by the c- kit receptor are quite diverse and include: cell proliferation, cell survival, cell adhesion, cell migration, secretion of mediators, cell differentiation and other post mitotic functions. The elucidation of the mechanisms of these different responses is of fundamental importance. Similar to other RTK's Kit mediates its action through a variety of cytoplasmic signal transducers including PI 3-kinase in KIT mediated adhesion of BMMC to a fibronectin matrix and potentiation of IgE mediated secretion in BMMC. To study Kit/PI 3-kinase mediated processes in other cell systems we will modify the c-kit gene in the germ line to mutate the PI 3-kinase binding site in the Kit receptor by using a cre-lox based strategy and derive mice homozygous for this mutation. We then will study the effect of the mutation on various targets of W and SI mutations, the dynamics of hematopoietic cell populations and their behavior in situations that require cell adhesion and migration, i.e. homing to the marrow compartment and mobilization of stem cells into the periphery. We will also modify tyrosine residues in the juxtamembrane region of the Kit receptor in ES cells which affect KL mediated cell proliferation but not suppression of apoptosis and investigate the consequences of this mutation in vivo. Finally, we will investigate the mechanism of Kit mediated suppression of radiation and factor deprivation induced apoptosis in mast cells.