RECEPTORS AND TRANSDUCTION MECHANISMS IN HUMAN PHAGOCYTES

人类吞噬细胞的受体和转导机制

• 批准号: 3960643
• 负责人: H L MALECH
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3960643
• 关键词: affinity labeling; chemotaxis; complement; electron microscopy; guanosine triphosphate; inflammation; mannose; monocyte; neutrophil; phagocytes; phagocytosis; phorbols; polysaccharides

Human neutrophils and monocytes are attracted to sites of inflammation and engulf invasive microorganisms or host cell debris. These phagocyte responses are mediated by surface receptors for a variety of substances released by infective agents or host, or derived from host plasma. The purpose of this project is to define the biochemical structure and transduction mechanisms of some of these surface receptors. More specifically, the present studies focus upon: (i) the receptor for bacterially derived formyl peptides, the formyl peptide chemotactic receptor (FPCR); (ii) the receptor for the particle-adherent C3 complement fragment iC3b (CR3); (iii) the pertussis toxin inhibitable GTP binding regulatory protein (Gi) in neutrophils required for FPCR and other receptor mediated cellular responses. Using affinity labeling of FPCR in conjunction with enzymatic cleavage or metabolic inhibitors we have shown that this receptor is highly N-glycosylated containing both complex- and high mannose-type polysaccharides. The polypeptide portion of FPCR appears to be of similar molecular weight with a similar proteolytic cleavage pattern in different phagocytic cells. N-glycosylation of FPCR is not required for ligand binding or stimulus-response coupling to occur. Using antibodies directed at different GTP regulatory proteins, we have shown that the Gi in neutrophils is immunologically distinct from the homologous protein in brain. Using immunogold labeling of CR3 we have shown by electron microscopy that average density of surface CR3 doubles after stimulation with phorbol myristate acetate and that these receptors are clustered on the cell surface. This arrangement may be important for the neutrophil adherence mediated by this receptor.

人类嗜中性粒细胞和单核细胞被炎症部位吸引 吞噬侵入性微生物或宿主细胞碎片。 这些吞噬细胞 反应是由表面受体介导的多种物质 由感染剂或宿主发行，或源自宿主等离子体。 这 该项目的目的是定义生化结构和 其中一些表面受体的转导机制。 更多的 具体而言，本研究的重点是：（i） 细菌衍生的甲基肽，甲基肽趋化性 受体（FPCR）; （ii）颗粒粘附C3补体的受体 片段IC3B（CR3）; （iii）百日咳毒素可抑制的GTP结合 FPCR和其他受体所需的中性粒细胞中的调节蛋白（GI） 介导的细胞反应。 使用FPCR的亲和力标记 我们显示的与酶促切割或代谢抑制剂的结合 该受体是高度N-糖基化的，含有复合物和 高甘露糖型多糖。 FPCR的多肽部分出现 具有相似的分子量，具有相似的蛋白水解裂解 不同吞噬细胞中的模式。 FPCR的n-糖基化不是 配体结合或刺激响应耦合所必需的。 使用 针对不同GTP调节蛋白的抗体，我们已经显示 中性粒细胞中的GI在免疫学上与同源物不同 大脑中的蛋白质。 使用CR3的免疫金标记我们已显示 电子显微镜，表面CR3的平均密度在 用佛比尔肉豆蔻酸酯刺激醋酸盐，这些受体是 聚集在细胞表面。 这种安排对 该受体介导的中性粒细胞依从性。