LOW MW G PROTEIN (RAP) IN NEUTROPHIL ACTIVATION

中性粒细胞参与人体免疫的许多方面 防御系统是炎症性疾病不可或缺的细胞成分 回应。了解中性粒细胞功能是如何被激活和 对于这些疾病的有效治疗干预，监管是至关重要的 区域。由结合启动的信号转导过程 已知的化学诱导剂受体配体涉及GTP结合 蛋白质(G蛋白质)。我们鉴定了一种新的低分子量G 人类中性粒细胞中的蛋白质，称为RAPL。初步数据显示 RAPL可能与中性粒细胞NADPH的蛋白成分相互作用 酶系统，并能对酶的活性产生影响 重组后的系统。此外，我们还展示了Rap1是一个 CAMP依赖的蛋白激酶的底物，这种磷酸化是 通过模拟配体化学诱导剂的条件/试剂来增强 受体。RAP1可能直接与N-甲酰基肽相互作用 受体，或者作为受体的附加转导 信号，或作为一种手段，以减弱中性粒细胞激活通过Gn。这个 RAPL磷酸化的调节作用尚未确定，但 显然与内源性介质抑制的能力有关 中性粒细胞功能。我们建议开发特定的RAPL探针和 纯化的RAPL蛋白制剂的物理和功能研究 RAP在人中性粒细胞中的大分子相互作用。互动 LO与中性粒细胞N-甲酰肽受体、NADPH氧化酶系统、 以及其他潜在的效应器(GAP)将被检查。的影响 RAP在调节这些相互作用方面的共价修饰将是 机械地确定和定义的。拟议的研究将使 美国也希望更好地了解中性粒细胞激活的调节 以阐明RAP及其相关G蛋白的正常细胞功能。

The neutrophil participates in many aspects of the body's immune defense system and is an integral cellular component of the inflammatory response. An understanding of how neutrophil functions are activated and regulated is paramount for effective therapeutic intervention in these areas. The signal transduction process that is initiated by the binding of chemoattractant receptor ligands is known to involve GTP binding proteins (G proteins). We have identified a novel low molecular weight G protein In human neutrophils, termed rapl. Preliminary data indicates that rapl may interact with protein components of the neutrophil NADPH oxidase system and can produce effects on the activity of the oxidase in a reconstituted system. We have additionally shown rap1 to be a substrate for cAMP-dependent protein kinase and this phosphorylation is enhanced by conditions/agents which mimic liganded chemoattractant receptor. rap1 may be able to interact directly with the N-formyl peptide receptor, either to serve as an additional transducer of receptor signalling, or as a means to attenuate neutrophil activation via Gn. The regulatory roles of rapl phosphorylation have yet to be defined but are clearly relevant to the ability of endogenous mediators to inhibit neutrophil function. We propose to develop specific rapl probes and purified rapl protein preparations to study physical and functional macromolecular interactions of rap in the human neutrophil. Interactions of Lo with neutrophil N-formyl peptide receptor, NADPH oxidase system, and other potential effectors (GAP's) will be examined. The influence of covalent modifications of rap in regulating these interactions will be determined and defined mechanistically. The proposed studies will enable us to better understand the regulation of neutrophil activation, as well as to elucidate the normal cellular roles of rap and related G proteins.