MECHANISMS OF LEUKOCYTE ACTIVATION AND CHEMOTAXIS

描述(改编自申请者的摘要)：白细胞在 在宿主防御入侵微生物方面发挥重要作用。他们的 产生超氧阴离子自由基和释放降解酶的能力 移行至炎症部位对此至关重要。 功能。然而，这些相同的响应也可以参与 形成众多的病理情况。重新介绍了 心肌血栓形成、中风后血流至缺血组织 冻伤是观察到的组织损伤的原因，这可能是 通过中性粒细胞的耗尽而减轻。化学引诱剂引发了他们的 与细胞表面受体偶联对中性粒细胞的影响 鸟嘌呤核苷酸结合调节蛋白(G蛋白)。的目标是 这项工作是为了了解涉及到的分子机制 白细胞G蛋白偶联趋化因子受体的激活 它们与受体信号和处理、受体相互作用有关 与细胞骨架和趋化性有关。 这项建议的具体目标包括确定角色 N-甲酰基多肽受体(FPR)激活的物理结合 G蛋白的受体。拟议中的实验还将确定 负责受体与受体相互作用的残基 细胞骨架及其主要成分肌动蛋白。我们将生成 重组FpR胞内区的突变及表达 这些在组织培养细胞系中进行功能分析。的角色 特定的残基，包括潜在的磷酸化残基，将被 根据受体的加工和趋化作用确定的，利用 我们最近开发的新系统。这些复杂的活动很可能 在受体磷酸化之后需要相互作用。利用这一点 系统中，我们还将研究(S)低分子量G蛋白Rho、Rac的作用 和CDC42在白细胞趋化中的作用。 从拟议研究中获得的资料可望延长我们的 对信号转导通路激活的认识 趋化受体的长期目标是这种知识将 导致控制中性粒细胞的治疗手段的发展 激活和防止过量的组织损伤 再灌流后中性粒细胞的激活。

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.