RECEPTOR INTERACTION WITH GTP REGULATORY PROTEINS

涉及肌动蛋白细胞骨架变化的复杂细胞反应， 细胞形态和迁移涉及信号转导的整合 由七跨膜受体（STMR）异三聚体调控的途径 G蛋白和酪氨酸激酶。一个整合的汇合点 STMR/G蛋白和酪氨酸激酶信号转导是控制低 分子量GTP结合蛋白，包括Ras和Rho家族 成员（Rho，Rac，Cdc 42）。 STMR/G蛋白的表征 与酪氨酸激酶和Ras/Rho GTP结合蛋白的整合将 在两个系统中定义：i.趋化因子受体信号传导 中性粒细胞，和ii.胃泌素释放肽受体调节 Gq和G12，13信号在成纤维细胞中的表达。中性粒细胞是主要的 疾病中炎症部位的组织损伤来源，包括 呼吸窘迫综合征和炎症性肠病。 中性粒细胞响应趋化因子迁移到炎症部位 例如IL 8。 IL 8受体和其他趋化因子受体是STMR 与G蛋白偶联，G蛋白响应趋化因子迅速激活 酪氨酸激酶林恩、Fgr、Hck和Syk。 我们将定义 中性粒细胞对趋化因子反应中这些激酶的需求 从具有三重靶向破坏的小鼠分离的嗜中性粒细胞 林恩、Fgr和Hck基因（林恩-/-/Fgr-/-/Hck-/-）和Syk基因（Syk- /-). 靶向破坏主要Src激酶（林恩、Fgr、Hck） 在中性粒细胞中表达，Syk将首次允许定义 这些激酶参与了趋化因子激活， 中性粒细胞及其在趋化因子刺激炎症反应中作用 应答包括GRP在内的神经肽在神经元间的作用 通讯，免疫系统信号，上皮细胞 增殖和组织重组。 GRP受体是STMR 偶联G蛋白Gq，11和G12，13。 肽配体已经被 其特征在于激活GRP受体，使得仅G12、13而不 GQ，11号被激活。 肽配体作为“偏向激动剂”发挥作用。 引发“不对称信号”。G12，13调节c-Jun激酶 途径和Rho家族GTP结合蛋白。 偏性激动剂提供 STMR选择性控制G蛋白信号传导的机制。 GRPR一级序列中的氨基酸是 将定义偏置信令。 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，这些研究将确定新的策略 用于开发药理学配体以调节 受体的功能，将有更多的选择性影响的目标 细胞和组织。

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 G12,13 signaling in fibroblasts. Neutrophils are a primary source of tissue injury at inflammatory sites in diseases including respiratory 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 the G proteins Gq,11 and G12,13. Peptide ligands have been characterized that activate the GRP receptor so that only G12,13 and not Gq,11 are activated. The peptide ligands function as "biased agonists" that induce "asymmetric signaling". G12,13 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 ligands to regulate subsets of receptor functions that will have much more selective effects on target cells and tissues.