ACTIVATION OF THE HUMAN NEUTROPHIL

描述：（改编自研究者摘要） 粘附中性粒细胞介导TNF-α分泌， 细胞外释放的氧自由基和颗粒内容物有助于 组织损伤 研究人员假设，不同的激活 蛋白激酶C同种型通过脂质介质起着积极的作用， 在这些事件中的负调节作用。 TNF-α激活了 效应酶PLC-γ和PI 3激酶，导致产生这种 脂质介质如甘油二酯和PIP 3以及PKC同种型的激活。 超氧化物生成的正信号传导是通过 p47-phox被DG依赖性PKC同种型磷酸化。 负 例如，通过PKC的信号传导抑制TNF-α结合的下调， 通过DG-非依赖性、PIP 3-依赖性的p60 TNF受体的磷酸化， zeta PKC。 研究者进一步提出，基于PKC的信号传导 需要1）细胞溶质PLC-γ和PI 3激酶进入膜 相关脂质，2）将胞质PKC同种型靶向PLC和PI 3 激酶并因此与脂质介质DG和PIP 3结合，和3）靶向PKC 同种型到它们的底物。 这个模型将通过实验来检验 重点关注四个具体目标：1）确定zeta PKC是否催化 p60 TNFR在死亡结构域的磷酸化，从而下调 受体。 2)使用DG依赖性PKC同种型的选择性缺失， 确定α、β和δ PKC在超氧化物生成中的作用。 第三章 建立TNF-α诱导PI 3激酶和磷脂酶C活化 PKC同种型通过PIP 3和DG的γ和差异活化。 4)定义 RACK（receptor for activated C kinase）在PLC共定位中的作用 和DG依赖的PKC同种型以及PKC和超氧化物的活化 一代 长期目标是确定积极和消极 TNF-α诱导的超氧化物生成激活的信号传导 中性粒细胞，从而可能导致靶向分子策略 控制炎症和组织损伤。

DESCRIPTION: (Adapted from investigator's abstract) The inflammatory mediator TNF-alpha elicits secretion by adherent neutrophils and the extracellular release of oxygen radicals and granule contents contributes to tissue damage. The investigator hypothesizes that activation of different protein kinase C isotypes by lipid mediators plays both positive and negative regulatory roles in these events. TNF-alpha triggers activation of effector enzymes PLC-gamma and PI3 kinase, leading to production of such lipid mediators as diglyceride and PIP3 and to activation of PKC isotypes. Positive signalling for superoxide generation is mediated through phosphorylation of p47-phox by DG-dependent PKC isotypes. Negative signalling by PKC elicits down regulation of TNF-alpha binding, for example by phosphorylation of the p60 TNF receptor by DG-independent, PIP3-dependent zeta PKC. The investigator further proposes that PKC-based signalling requires 1) access of cytosolic PLC-gamma and PI3 kinase to membrane associated lipids, 2) targeting of cytosolic PKC isotypes to PLC and PI3 kinase and thus to lipid mediators DG and PIP3, and 3) targeting of PKC isotypes to their substrates. This model will be tested through experiments focusing on four specific aims: 1) Determine if zeta PKC catalyzes phosphorylation of p60 TNFR in the death domain and thereby down regulates the receptor. 2) Use selective deletion of DG-dependent PKC isotypes to define roles for alpha, beta, and delta PKC in superoxide generation. 3) Establish TNF-alpha elicited activation of PI3 kinase and phospholipase C gamma and differential activation of PKC isotypes by PIP3 and DG. 4) Define a role for RACK (receptor for activated C kinase) in co-localization of PLC and DG-dependent PKC isotypes and activation of PKC and superoxide generation. The long term objective is to define positive and negative signalling for TNF-alpha induced activation of superoxide generation by neutrophils, thereby potentially leading to targeted molecular strategies for control of inflammation and tissue damage.