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 七跨膜受体（STMR）异源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汇合点 信号传导是低分子量GTP结合蛋白的控制，包括Ras和Rho家族成员 (Rho，Rac，Cdc42）。STMR/G蛋白与酪氨酸激酶和Ras/Rho GTP整合的表征 结合蛋白将在两个系统中定义：i.中性粒细胞中的趋化因子受体信号传导，和ii.胃泌素 释放肽（GRP）受体调节成纤维细胞中的Gq和G1213信号传导。中性粒细胞是主要的 包括呼吸窘迫综合征和炎性 肠道疾病。中性粒细胞响应于趋化因子如IL 8而迁移至炎症部位。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应答， 激活酪氨酸激酶林恩、Fgr、Hck和Syk。我们将定义这些激酶的需求， 使用从具有三重靶向破坏的小鼠分离的中性粒细胞， 林恩、Fgr和Hck基因（林恩/Fgr/Hck）和Syk基因（Syk）。有针对性地破坏初选 在中性粒细胞和Syk中表达的Src激酶（林恩、Fgr、Hck）将首次允许定义 这些激酶参与中性粒细胞的趋化因子活化，以及它们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与神经元的通讯、信号传导中起作用 在免疫系统中，上皮细胞增殖和组织重建。GRP受体是STMR偶联物， G蛋白Gn和G1213。肽配体已被表征为激活GRP受体， 只有G1213而不是G1214被激活。肽配体作为“偏向激动剂”起作用，其诱导“不对称性”， 信号”。G1213调节c-Jun激酶途径和Rho家族GTP结合蛋白。偏性激动剂 提供了一种通过STMR选择性控制G蛋白信号传导的机制。GRPR中的氨基酸 将定义偏置信令所需的主序列。有偏见的激动的后果， 细胞生长、基因表达和肌动蛋白细胞骨架的调节将被定义。累积起来，研究 将为开发调节受体功能亚群的药理学配体定义新的策略 这将对靶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.