MOLECULAR MECHANISMS CYTOKINE RECEPTOR SIGNALING

描述：细胞因子通过特定的膜受体调节 造血细胞发育 许多细胞内信号 途径被激活的细胞因子受体刺激;然而， 参与信号转导启动的分子事件，以及 不同的途径控制造血细胞的存活、增殖， 分化，在很大程度上是未知的。 异常造血细胞生长 可能导致疾病的发展，包括骨髓增生性疾病 疾病、白血病或淋巴瘤。 此外，生产不足的关键 造血细胞类型可能危及健康和生存。 整体 这个项目的目标是定义特定蛋白质的作用：蛋白质 寡聚化事件在细胞因子受体信号激活中起作用 转导，并确定Jak和Stat信号的特异性， 红细胞发育 在目标1中，受体二聚化的作用 胞质区域在下游信号转导的激活中起作用 途径将被检查，使用促红细胞生成素受体（EpoR）作为一个 血二聚体细胞因子受体的模型。 特异性二聚化基序将 与EpoR胞质尾融合。 胞质尾效应 二聚化，在不存在或存在质膜缔合的情况下， 信号转导通路的激活导致细胞增殖 将被确定。 在目的2中，Jak的同源或异源二聚化的作用 蛋白酪氨酸激酶在内源性激酶调节中的作用 活动将进行研究。 含有Jak 1或Jak 3结合的嵌合EpoR 将产生结构域，并将确定配体诱导的 受体二聚化激活各自的Jak激酶。 二聚 基序也将直接与Jak 1、Jak 2或Jak 3 cDNA融合，以确定 如果特异性Jaks之间的同源或异源二聚化调节它们的 活动 在第三个目标中，研究人员将确定来自 Jak 2和Stat 5通过产生嵌合体而对红系发育具有特异性 具有改变的Jak或Stat信号转导潜力的EpoR。 这些将是 引入生长因子依赖性造血细胞中以分析 对体外细胞增殖的影响。 的组成活性形式 嵌合受体将被引入造血祖细胞 和通过集落形成测定分析的体外红系分化。 对体内红细胞生成的影响和对发育的贡献 将在感染重组逆转录病毒的小鼠中分析白血病。

DESCRIPTION: Cytokines act through specific membrane receptors to regulate hematopoietic cell development. A number of intracellular signaling pathways are stimulated by activated cytokine receptors; however, the molecular events involved in initiation of signal transduction, and how the different pathways control hematopoietic cell survival, proliferation, and differentiation, are largely unknown. Abnormal hematopoietic cell growth can lead to the development of disease, including myeloproliferative disorders, leukemia, or lymphoma. In addition, underproduction of crucial hematopoietic cell types can compromise health and survival. The overall goals of this project are to define the role specific protein:protein oligomerization events play in activation of cytokine receptor signal transduction, and to determine the specificity of Jak and Stat signals in erythroid development. In Aim 1 the role dimerization of the receptor cytoplasmic region plays in activation of downstream signal transduction pathways will be examined, using the erythropoietin receptor (EpoR) as a model of hemodimeric cytokine receptors. Specific dimerization motifs will be fused to the EpoR cytoplasmic tail. The effects of cytoplasmic tail dimerization, in the absence or presence of plasma membrane association, on the activation of signal transduction pathways leading to cell proliferation will be determined. In Aim 2 the role of homo-or heterodimerization of Jak protein tyrosine kinases in the role of regulation of intrinsic kinase activity will be studied. Chimeric EpoRs containing Jak1 or Jak3 binding domains will be generated and it will be determined if ligand-induced receptor dimerization activates the respective Jak kinase. Dimerization motifs will also be fused directly to Jak1, Jak2, or Jak3 cDNAs to determine if homo- or heterodimerization between specific Jaks regulates their activity. In the third aim, the investigator will determine if signals from Jak2 and Stat5 are specific for erythroid development by generating chimeric EpoRs with altered Jak or Stat signal transduction potential. These will be introduced into growth-factor dependent hematopoietic cells to analyze effects on cell proliferation in vitro. Constitutively active forms of the chimeric receptors will be introduced into hematopoietic progenitor cells and in vitro erythroid differentiation analyzed by colony-forming assays. Effects on in vivo erythropoiesis and contribution to development of leukemia will be analyzed in mice infected with recombinant retroviruses.