Membrane Traffic Regulation of NK Cell Function

自然杀伤细胞的功能是由细胞膜上抑制性和激活性受体表达的平衡引起的。该计划的这个单元将定义NK细胞受体表达的翻译后控制所涉及的膜交通途径，以确定这些途径的调节如何影响NK细胞功能。仅对NK受体的内吞途径进行了有限的分析，并且没有对NK受体的生物合成途径进行分析。本单元的研究纠正了这些信息的缺陷，目的是比较激活的内吞和生物合成调节。 和抑制性KIR，以及定义影响KIR折叠和稳定性的分子伴侣途径。此外，将定义调节NK细胞-靶细胞在突触处相互作用的膜交通途径。具体目标如下。目的1是表征抑制性（KIR 2DL 1）和活化性（KIR 2DS 1）NK受体的内吞行为，以验证每类受体的表面活性受对配体的不同反应调节的假设。还将评估CDS信号传导在KIR内吞作用中的作用。目的2是验证KIR 3DL 1基因座多态性可以通过影响生物合成途径中的膜交通行为来影响NK细胞质膜受体表达的假设，并比较抑制性和激活性KIR的生物合成途径。这些研究将建立影响KIR受体表达水平的分子伴侣途径， 受体的多态性变化，以及感染期间的应激效应。目的3是测试的假设，网格蛋白介导的膜交通在NK细胞的目标突触所需的功能性生物标志物-目标的相互作用。将使用抑制网格蛋白表达的技术分析网格蛋白参与NK细胞的配体反式内吞作用和靶细胞的细胞毒性。通过为该计划的该单元提出的研究定义受体运输途径，可以了解NK受体的受体多态性和信号传导途径如何影响对确定个体NK细胞活性至关重要的相对受体表达水平。需要这些信息来了解HIV感染期间NK细胞群的功能相互作用。

Natural killer cell function results from the balance of expression of inhibitory and activating receptors at the plasma membrane. This unit of the program will define membrane traffic pathways involved in post-translational control of NK cell receptor expression in order to determine how regulation of these pathways can influence NK cell function. There has only been limited analysis of endocytic pathways of NK receptors and no NK receptors have been analyzed for their biosynthetic pathways. The studies in this unit redress these deficits of information with the goals of comparing endocytic and biosynthetic regulation of activating and inhibitory KIRs, as well as defining chaperone pathways that influence KIR folding and stability. In addition, membrane traffic pathways regulating NK cell-target cell interactions at the synapse will be defined. The specific aims are as follows. Aim 1 is to characterize the endocytic behavior of inhibitory (KIR2DL1) and activating (KIR2DS1) NK receptors to test the hypothesis that surface activity of each class of receptor is regulated by different responses to ligand. The role of CDS signaling in KIR endocytosis will also be assessed. Aim 2 is to test the hypothesis that polymorphism of the KIR3DL1 locus can influence receptor expression at the NK cell plasma membrane by affecting membrane traffic behavior in the biosynthetic pathway and to compare the biosynthetic pathways of inhibitory and activating KIR. These studies will establish the chaperone pathways that influence levels of KIR receptor expression and that are susceptible to polymorphic variation of the receptors, as well as to stress effects during infection. Aim 3 is to test the hypothesis that clathrin-mediated membrane traffic at the NK cell-target synapse is required for functional killer-target interactions. The involvement of clathrin in ligand trans-endocytosis by NK cells and in cytotoxicity of target cells will be analyzed using techniques that inhibit clathrin expression. Definition of receptor trafficking pathways by the studies proposed for this unit of the program makes it possible to understand how receptor polymorphisms and the signaling pathways of NK receptors could influence the relative receptor expression levels that are critical for determining individual NK cell activity. This information is needed to appreciate the functional interplay of NK cell populations operating during HIV infection.