MECHANISMS OF LEUKOCYTE ACTIVATION AND CHEMOTAXIS

描述（改编自申请人摘要）：白细胞起作用， 在宿主防御入侵微生物中的重要作用。他们的 产生超氧自由基和释放降解酶的能力 在迁移到炎症部位后， 功能然而，这些相同的响应也可以参与 形成多种病理状态。重新引入 心肌血栓形成、中风或 冻伤是观察到的组织损伤的原因， 通过中性粒细胞的消耗而减轻。化学引诱剂引起它们的 通过与细胞表面受体结合对中性粒细胞的影响， 鸟嘌呤核苷酸结合调节蛋白（G蛋白）。的目标 这项工作是为了了解参与的分子机制， 白细胞G蛋白偶联的化学引诱物受体的激活， 它们涉及受体信号传导和处理，受体相互作用 细胞骨架和趋化性。 这项建议的具体目标包括确定 的N-甲酰肽受体（FPR）激活I的物理结合 G蛋白的受体。拟议的实验还将确定 负责受体与受体相互作用的残基 细胞骨架及其主要成分之一肌动蛋白。我们将产生 重组FPR的胞内结构域中的突变，并表达 这些在组织培养细胞系中用于功能分析。的作用 特定的残基，包括潜在的磷酸化残基，将被 确定相对于受体加工和趋化性，利用 我们最近开发的新系统。这些复杂的活动可能 需要受体磷酸化后的相互作用。利用该 系统，我们还将研究低分子量G蛋白rho，rac 和CDC 42在白细胞趋化性中的作用。 从拟议的研究中获得的信息预计将扩大我们的 信号转导通路的激活的知识， 化学引诱物受体的长期目标，这样的知识将 导致控制中性粒细胞的治疗手段的发展 激活和防止组织损伤所造成的过度 再灌注后中性粒细胞的活化。

DESCRIPTION (Adapted from applicant's abstract): Leukocytes play an important role in host defense against invading microorganisms. Their ability to generate superoxide radicals and release degradative enzymes following migration to sites of inflammation is essential for this function. However, these same responses can also participate in the formation of numerous pathological conditions. The re-introduction of blood flow to ischaemic tissues following myocardial thrombosis, stroke or frostbite is responsible for the observed tissue damage, which can be alleviated by the depletion of neutrophils. Chemoattractants elicit their effects on neutrophils by binding to cell surface receptors coupled to guanine nucleotide-binding regulatory proteins (G proteins). The goal of this work is to understand the molecular mechanisms involved in the activation of leukocyte G protein-coupled chemoattractant receptors as they pertain to receptor signaling and processing, receptor interactions with the cytoskeleton and chemotaxis. The specific aims of this proposal include the determination of the role of the N-formyl peptide receptor (FPR) activation I the physical binding of the receptor to G protein. The proposed experiments will also determine residues responsible for the interaction of the receptor with the cytoskeleton and one of its major components, actin. We will generate mutations in the intracellular domains of the recombinant FPR and express these in tissue culture cell lines for functional analysis. The roles of specific residues, including potentially phosphorylated residues, will be determined with respect to receptor processing and chemotaxis utilizing a novel system we have recently developed. These complex activities likely require interactions following receptor phosphorylation. Utilizing this system, we will also examine the role(s) of the low MW G proteins rho, rac and cdc42 in leukocyte chemotaxis. Information obtained from the proposed studies is expected to extend our knowledge of the activation of signal transduction pathways by chemoattractant receptors with the long term goal that such knowledge will lead to the development of therapeutic means to control neutrophil activation and prevent the tissue damage resulting from the excessive activation of neutrophils following reperfusion.