SIGNAL TRANSDUCTION IN ERYTHROID CELLS

红细胞中的信号转导

• 批准号: 6109748
• 负责人: LEONARD Ira ZON
• 金额: --
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-07-01 至 1999-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6109748
• 关键词: Anura; cell cycle; cell differentiation; cell growth regulation; chimeric proteins; developmental genetics; enzyme activity; enzyme induction /repression; erythroid stem cell; erythropoiesis; gene expression; laboratory mouse; laboratory rabbit; mitogen activated protein kinase; protein kinase; protein structure function; transcription factor; transfection

Vertebrate cells have adapted ancient signal transduction cascades that respond to changes in the environment. Ligand binding of receptor tyrosine kinases potently stimulates mitogen activated protein kinase (MAPK), whereas TNFalpha, IL-1, and UV-irradiation activates the stress- activated protein kinases (SAPK, also called JNK). The MAPK cascade consists of three kinases (raf/MEK/MAPK) that ultimately phosphorylate and activate transcription factors such as the ets-related TCF. The SAPK cascade leads to the phosphorylation and activation of c-jun. Recently, we isolated a cDNA, SEK1, from a murine erythroleukemia cell library that functions as an immediate upstream activator of SAPK. We also demonstrated that the kinase MEKK is an activator of SEK1, thus establishing the SAPK cascade (MEKK/SEK/SAPK). A third vertebrate cascade is stress-activated, and includes the kinase XMEK3 (also called MKK3), which activates a MAP kinase homolog called p38. We propose to determine which of these cascades are activated and/or required for normal erythropoiesis. Erythroid cells lines (i.e. MEL and Ba/F3) and normal erythroid progenitors will be transfected with vectors that express tagged MAPK, SAPK, or p38. Following extracellular stimulation to promote cell proliferation or differentiation (i.e. erythropoietin or DMSO), specific MAP kinase activity will be evaluated. Expression of dominant negative mutants of the specific activators (MEK, SEK, and XMEK3) will be used to define the requirement of each cascade for normal erythroid development and prevention of cell death. In yeast, ste20-like kinases function as upstream activators of MAPK cascades. We have isolated cDNAs encoding several distinct mouse homologs of ste20 that are expressed in erythroid cells and are likely to be upstream activators of vertebrate MAP kinase cascades. By constructing and expressing mutants of the ste20 kinase members, we plan to determine their function in erythroid cells. An analysis of the cascades activated by these ste20 family members and the upstream signals that lead to their activation will be undertaken. These studies will provide a better understanding of the role of the MAPK cascades in cell proliferation, death, or differentiation of hematopoietic cells. The pharmacologic manipulation of these pathways in vivo will be useful to treat anemia of chronic disease, sickle cell anemia, thalassemia and leukemia.

脊椎动物细胞已适应古代信号转导级联 响应环境的变化。 受体的配体结合 酪氨酸激酶有效刺激有丝分裂原活化的蛋白激酶 （MAPK），而Tnfalpha，IL-1和UV-irradiation激活应力 - 活化的蛋白激酶（SAPK，也称为JNK）。 MAPK级联 由三个激酶（RAF/MEK/MAPK）组成，最终磷酸化 并激活转录因子，例如与ETS相关的TCF。 树苗 级联导致C-Jun的磷酸化和激活。 最近， 我们从一个鼠红细胞藻细胞库中隔离了一个cDNA，sek1 充当SAPK的直接上游激活剂。我们也是 证明激酶MEKK是SEK1的激活剂，因此 建立SAPK CASCADE（MEKK/SEK/SAPK）。第三个脊椎动物级联 被压力激活，包括激酶XMEK3（也称为MKK3）， 激活称为p38的MAP激酶同源物。 我们建议确定 这些级联反应的哪一个被激活和/或普通所需 红细胞生成。 红细胞细胞系（即MEL和BA/F3）和正常 红细胞祖细胞将用表达的向量转染 标记的MAPK，SAPK或P38。 遵循细胞外刺激 促进细胞增殖或分化（即促红细胞生成素或 DMSO）将评估特定的MAP激酶活性。 表达 特定激活剂的主要负突变体（MEK，SEK和 xmek3）将用于定义每个级联的正常要求 红细胞发育和预防细胞死亡。 在酵母中，类似于Ste20 激酶充当MAPK Cascades的上游激活剂。 我们有 孤立的cDNA编码几种不同的ste20小鼠同源物 在红细胞细胞中表达，可能是 脊椎动物地图激酶级联反应。 通过构建和表达突变体 在Ste20激酶成员中，我们计划确定其功能 红细胞细胞。 对这些Ste20激活的级联反应的分析 家庭成员和导致激活的上游信号 将进行。 这些研究将提供更好的理解 MAPK级联反应在细胞增殖，死亡或 造血细胞的分化。 药理操作 在体内这些途径中，对治疗慢性贫血很有用 疾病，镰状细胞贫血，丘脑贫血和白血病。