Atypical MAP Kinase Signal Transduction

项目概要： MAP 激酶 (MAPK) 是许多信号转导的调节成分 影响真核细胞生长、分化和运动的途径。相对而言 对于非典型 MAPK（代表为 MAPK15/Erk8（哺乳动物中的 MAPK15/Erk8）仅存在于具有细胞运动性的真核生物中。非典型 MAPK 不会被传统的 MAPK 激酶和外部信号激活 除变形虫网网柄菌（一种模式生物）外，触发激活尚不清楚 用于趋化运动和发育。我们发现盘基网柄菌 非典型 MAPK Erk2 对于多种信号的趋化运动至关重要。在我们的 之前资助的研究我们还发现 Erk2 磷酸化特定的 GATA 转录因子 GtaC 的残基，导致该因子易位 从细胞核到细胞质响应至少两个趋化信号 促进不同的细胞命运。我们还证明 Erk2 激酶活性并不 体内激活所需，表明非常规 MAPK 激酶调节 非典型 MAPKs 而不是自磷酸化。拟议的研究将 研究 Erk2 是否通过差异修饰促进不同的细胞命运 GtaC或通过其他转录因子的调节。我们将使用 GFP 标记 GtaC 绘制 Erk2 对接位点并将其与其他组的对接位点进行比较 MAPK。我们还将使用免疫共沉淀、质谱和遗传分析 分析以确定信号通路中与 Erk2 关联并发挥作用的蛋白质 并鉴定直接调节 Erk2 激活的蛋白质。该项目的结果是 有望确定非典型 MAPK 调节和功能的具体机制， 揭示非典型 MAPK 信号在趋化运动和细胞命运中的作用 确定可以指导其他生物体中 MAPKs 的研究，例如 哺乳动物。

Project Summary: MAP kinases (MAPKs) are regulatory components of many signal transduction pathways that impact eukaryotic cell growth, differentiation, and movement. Relatively little is known about the function and regulation of atypical MAPKs (represented by MAPK15/Erk8 in mammals) found only in eukaryotes that have cell motility. Atypical MAPKs are not activated by conventional MAPK kinases and the external signals that trigger activation are not known except in the amoeba Dictyostelium, a model organism for chemotactic movement and development. We have found that the Dictyostelium atypical MAPK, Erk2, is essential for chemotactic movement to multiple signals. In our previously funded research we also discovered that Erk2 phosphorylates specific residues of a GATA transcription factor, GtaC, resulting in the translocation of this factor from the nucleus to the cytoplasm in response to at least two chemotactic signals that promote different cell fates. We have also demonstrated that Erk2 kinase activity is not required for activation in vivo indicating that an unconventional MAPK kinase regulates atypical MAPKs rather than autophosphorylation. The proposed research will investigate if Erk2 promotes different cell fates through the differentially modification of GtaC or through the regulation of other transcription factors. We will use a GFP tagged GtaC to map Erk2 docking sites and compare these to docking sites of other groups of MAPKs. We will also use co-immunoprecipitations, mass spectrometry, and genetic analysis to identify proteins that associate and function with Erk2 in signaling pathways and identify proteins that directly regulate Erk2 activation. The results of this project are expected to identify specific mechanisms of atypical MAPK regulation and function and uncover roles for atypical MAPK signaling in chemotactic movement and cell fate determination that can guide the research of MAPKs in other organisms such as mammals.