Regulation of Interleukin-5 Receptor Signaling

描述(申请人提供)：马丁内斯-莫奇吉巴博士是博士后 他的研究兴趣是确定调解分子事件 白介素5(IL-5)诱导的信号终止。了解这些 机制应为IL-5介导的调控提供新的靶点 炎症反应，如过敏性炎症和哮喘。研究报告 学者发展奖(K22)将帮助马丁内斯-莫奇吉巴博士完成 她的研究目标以及获得终身教职的助理教授 预约。IL-5特异性促进肿瘤细胞分化和存活 嗜酸性粒细胞，在嗜酸性炎症的病理生物学中起关键作用 过敏性疾病和哮喘。IL-5通过以下途径启动其细胞效应 与异二聚体IL-5受体结合导致激活 JAK！STAT、RAS/MAPK和PI3激酶信号通路。这样做的目的是 建议是描绘启动、调节和 调节IL-5信号转导的终止。目标I.阐明 启动白介素5诱导信号蛋白酶体终止的分子事件 转导。我们将确定Betac的酪氨酸或丝氨酸磷酸化 是其蛋白酶体降解所必需的，通过使用特定的抑制剂 这些激酶，以及这些β-c的定点突变体 磷酸化位点。我们还将确定β-c泛素化是否 对其蛋白酶体的降解是必要的。目的2.研究分子 介导细胞内吞和溶酶体降解的机制 IL-5刺激后的长度和截短的IL-5R。潜在的内吞作用 β-c和IL-5R-α胞质区域的共同序列将 评估它们在配体诱导的全长内吞作用中的作用 通过靶向缺失和定点突变获得受体。目标3. 确定其他共享的细胞因子信号受体链是否 蛋白酶体调控。其他共享信号受体链，如伽马- 将分析C/IL-4R-α对其降解的敏感性 配体刺激后的蛋白酶体。目的4.演示生理学 细胞因子诱导β-c异型脱敏的后果 活体内的受体。GM-CSF和IL-3过表达的转基因小鼠将 评估他们在接受治疗后发生嗜酸性粒细胞增多症的能力 高剂量的IL-5。此外，来自IL-5转基因小鼠的嗜酸性粒细胞将 分离并分析其进一步被GM-CSF或 IL-3体外培养。

DESCRIPTION (provided by applicant): Dr. Martinez-Moczygemba is a postdoctoral fellow whose research interest is to identify the molecular events mediating interleukin-5 (IL-5)-induced signal termination. Understanding these mechanisms should provide novel targets for the modulation of IL-5-mediated inflammatory responses such as allergic inflammation and asthma. The Research Scholar Development Award (K22) will aid Dr. Martinez-Moczygemba to accomplish her research goals as well as to attain a tenure-track assistant professor appointment. IL-5 specifically promotes the differentiation and survival of eosinophils and is critical to the pathobiology of eosinophilic inflammation in allergic disorders and asthma. IL-5 initiates its cellular effects by binding to a heterodimeric IL-5 receptor leading to the activation of the JAK!STAT, Ras/MAPK, and the PI3 kinase signaling pathways. The goal of this proposal is to delineate the molecular events that initiate, mediate, and modulate termination of IL-5 signal transduction. Aim I. Elucidate the molecular events that initiate proteasome termination of IL-5-induced signal transduction. We will determine if tyrosine or serine phosphorylation of betac is required for its proteasomal degradation by using specific inhibitors of these kinases, as well as making site-directed mutants of these beta-c phosphorylation sites. We will also determine if beta-c ubiquitination is necessary for its proteasomal degradation. Aim 2. Investigate the molecular mechanisms that mediate endocytosis and lysosomal degradation of the full length and truncated IL-5R following IL-5 stimulation. Potential endocytic consensus sequences in the cytoplasmic domains of beta-c and IL-5R-alpha will be evaluated for their role in ligand-induced endocytosis of the full-length receptors by targeted deletions and by site-directed mutagenesis. Aim 3. Determine if other shared cytokine signaling receptor chains are proteasomally-regulated. Other shared signaling receptor chains such as gamma- c / IL-4R-alpha will be analyzed for their susceptibility to degradation by proteasomes following ligand stimulation. Aim 4. Demonstrate the physiologic consequence of cytokine-induced heterotypic desensitization of beta-c receptors in vivo. GM-CSF and IL-3 over-expressing transgenic mice will be evaluated for their ability to develop eosinophilia following treatment with high doses of IL-5. In addition, eosinophils from IL-5 transgenic mice will be isolated and analyzed for their ability to be further stimulated by GM-CSF or IL-3 in vitro.