RECEPTOR INTERACTION WITH GTP REGULATORY PROTEINS

涉及肌动蛋白细胞骨架、细胞形状和迁移变化的复杂细胞反应涉及 七种跨膜受体(STMR)异三聚体调控的信号转导通路的整合 G蛋白和酪氨酸激酶。STMR/G蛋白与酪氨酸激酶整合的一个聚合点 信号转导是包括Ras和Rho家族成员在内的低分子GTP结合蛋白的控制 (Rho，RAC，CDC42)。STMR/G蛋白与酪氨酸激酶和Ras/Rho GTP整合的特性 结合蛋白将在两个系统中定义：一是中性粒细胞中趋化因子受体信号传递；二是。胃泌素 GRP受体对成纤维细胞GQ和G1213信号的调节中性粒细胞是主要的 包括呼吸窘迫综合征和炎症性疾病在内的炎症部位的组织损伤来源 肠病。中性粒细胞在趋化因子如IL8的作用下迁移到炎症部位。IL8 受体和其他趋化因子受体是与G蛋白偶联的STMR，G蛋白对趋化因子迅速反应 激活酪氨酸激酶LYN、FGR、HCK和SyK。我们将在以下文件中定义这些Kinase的要求 中性粒细胞对趋化因子的反应使用从具有三重靶向干扰的小鼠分离的中性粒细胞 Lyn、Fgr和HCK基因(Lyn^/Fgr^‘/HCk“’)和Syk基因(Syk”‘)。对主要业务的定向中断 在中性粒细胞和Syk中表达的SRC激酶(Lyn、FGR、HCK)将首次允许定义 这些激酶参与中性粒细胞趋化因子的激活及其在趋化因子刺激中的作用 炎症反应。包括GRP在内的神经肽在神经元间通讯、信号传递中的作用 在免疫系统中，上皮细胞增殖和组织重构。GRP受体是STMR偶联 G蛋白Gn和G1213。已确定的多肽配体可以激活GRP受体，从而 只有G1213而不是G，被激活。这些多肽配体的功能是“有偏向的激动剂”，可诱导“不对称” G1213调节c-jun激酶途径和Rho家族GTP结合蛋白。偏向激动剂 为STMR选择性调控G蛋白信号转导提供机制。GRPR中的氨基酸 将定义偏置信令所需的主序列。有偏见的激励主义的后果 将定义细胞生长、基因表达和肌动蛋白细胞骨架的调控。总体而言，这些研究 将为开发调节受体功能亚群的药理配体确定新的策略 这将对目标细胞和组织产生更多的选择性影响。

Complex cellular responses involving changes in the actin cytoskeleton, cell shape and migration involve the integration of signal transduction pathways regulated by seven transmembrane receptor (STMR) heterotrimeric G proteins and tyrosine kinases. A convergence point for the integration of STMR/G protein and tyrosine kinase signaling is the control of low molecular weight GTP binding proteins including Ras and Rho family members (Rho, Rac,Cdc42). Characterization of STMR/G protein integration with tyrosine kinases and Ras/Rho GTP binding proteins will be defined in two systems: i. chemokine receptor signaling in the neutrophil, and ii. gastrin releasing peptide (GRP) receptor regulation of Gq and G1213 signaling in fibroblasts. Neutrophils are a primary source of tissue injury at inflammatory sites in diseases includingrespiratory distress syndrome and inflammatory bowel disease. Neutrophils migrate to an inflammatory site in response to chemokines such as IL8. The IL8 receptor and other chemokine receptors are STMR coupled to G proteins which in response to chemokine rapidly activate the tyrosine kinases Lyn, Fgr, Hck and Syk. We shall define the requirement of these kinases in neutrophil responses to chemokines using neutrophils isolated from mice having the triple targeted disruption of the Lyn, Fgr and Hck genes (Lyn^/Fgr^'/Hck"'") and the Syk gene (Syk"'"). The targeted disruption of the primary Src kinases (Lyn, Fgr, Hck) expressed in neutrophils and Syk will allow for the first time to define the involvement of these kinases in chemokine activation of the neutrophil and their role in chemokine stimulated inflammatory responses. Neuropeptides including GRP function in neuron-to-neuron communication, signaling in the immune system, epithelial cell proliferation and tissue restructuring. The GRP receptor is a STMR coupling to the G proteins G n and G1213. Peptide ligands have been characterized that activate the GRP receptor so that only G1213 and not G ,, are activated. The peptide ligands function as "biased agonists" that induce "asymmetric signaling". G1213 regulates the c-Jun kinase pathway and Rho family GTP binding proteins. Biased agonists provide a mechanism for the selective control of G protein signaling by STMRs. The amino acids in the GRPR primary sequence that are required for biased signaling will be defined. The consequence of biased agonism on cell growth, gene expression and regulation of the actin cytoskeleton will be defined. Cumulatively, the studies will define new strategies for the development of pharmacological ligandsto regulate subsets of receptor functions that will have much more selective effects on target cells and tissues.