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， 细胞的形态和迁移涉及信号转导的整合 七种跨膜受体(STMR)异源三聚体调控的通路 G蛋白和酪氨酸激酶。积分的一个聚合点 STMR/G蛋白和酪氨酸激酶信号转导是控制Low 分子量GTP结合蛋白包括Ras和Rho家族 成员(RHO、RAC、CDC42)。STMR/G蛋白的特性研究 与酪氨酸激酶和Ras/Rho GTP结合蛋白的整合 被定义在两个系统中：I.趋化因子受体信号转导 中性粒细胞，II。胃泌素释放肽受体的调节 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 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。 中性粒细胞对趋化因子的反应迁移到炎症部位 例如IL8。IL8受体和其他趋化因子受体是STMR 与G蛋白偶联，G蛋白在趋化因子的响应下迅速激活 酪氨酸激酶LYN、FGR、HCK和SyK。我们将定义 中性粒细胞对趋化因子反应中对这些激酶的需求 从具有三重靶向干扰的小鼠中分离出的中性粒细胞 Lyn、Fgr和HCK基因(Lyn-/-/Fgr-/-/HCK-/-)和Syk基因(Syk-/-)。 /-)。初级Src激酶(LYN、FGR、HCK)的靶向性破坏 在中性粒细胞和Syk中表达将首次允许定义 这些激酶在趋化因子激活中的作用 中性粒细胞及其在趋化因子刺激炎症中的作用 回应。包括GRP功能的神经肽在神经元到神经元中的作用 免疫系统中的通讯、信号、上皮细胞 增殖和组织重建。GRP受体是一种STMR 偶联G蛋白Gq，11和G12，13。 其特征是激活GRP受体，使只有G12，13和不 GQ，11被激活。这些多肽配体的功能是“偏向激动剂”。 这会引发“不对称信号”。G12、13对c-jun激酶的调节作用 途径和Rho家族GTP结合蛋白。有偏见的激动剂提供 短串联重复序列选择性调控G蛋白信号的机制。 GRPR一级序列中的氨基酸是 将定义有偏差的信令。有偏见的激励主义的后果 细胞生长、基因表达与肌动蛋白细胞骨架的调控 将会被定义。总而言之，这些研究将定义新的战略 用于开发药物配体来调节亚群 受体功能将对靶点产生更多的选择性作用 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.