Expression of vitronectin receptor on human NK cells and its role in protein phosphorylation, cytokine production, and cell proliferation.
Expression of vitronectin receptor on human NK cells and its role in protein phosphorylation, cytokine production, and cell proliferation.
复制标题
玻连蛋白受体在人 NK 细胞上的表达及其在蛋白质磷酸化、细胞因子产生和细胞增殖中的作用。
作者：
H. Rabinowich;Wen;A. Amoscato;R. Herberman;T. Whiteside
在本文中，我们提供的证据表明，玻连蛋白受体（VNR）的α v β 3的人NK细胞上表达。新鲜纯化的NK细胞上的VNR的存在下，通过流式细胞仪分析，以及生化，125碘标记的表面乳过氧化物酶标记和免疫沉淀后证明。在非还原条件下，分别对α v和α v β 3具有特异性的mAb LM 142和LM 609沉淀出分子量约为155和110 kDa的α链和β链的异源二聚体。在还原条件下，α链的分子量明显降低，这可能是由于释放了通过内部二硫键与α v链连接的20 - 30 kDa蛋白质所致。在NK细胞上表达的整合素α v β 3变得有功能，即，仅在细胞活化后或提供具有额外信号的共刺激时，才能结合其配体玻连蛋白（VN）。因此，NK细胞仅在IL-2活化后粘附于塑料固定的VN，并且含有RGD的合成肽或特异于α v β 3复合物的mAb抑制这种结合。为了评估VNR在信号转导中的作用，使用抗β 3 mAb将VNR聚集在NK细胞上，从而模拟粘附接触形成期间发生的过程。新鲜NK细胞上VNR的交联刺激了几种细胞内蛋白酪氨酸残基的磷酸化。酪氨酸磷酸化的主要增加，观察到在蛋白质的近似分子量为75和120 kDa。因此，NK细胞上VNR的信号转导诱导细胞内蛋白激酶的活化。VNR在NK细胞上的配体接合也共刺激NK细胞的细胞因子产生和增殖。NK细胞与塑料固定的VN的结合充当与抗Fc γ RIII或IL-2的共刺激物，以产生IFN-γ、TNF-α和细胞增殖。我们的研究结果表明，VNRs的占用和随后的聚集在人类NK细胞的激活和功能中发挥作用。
In this paper, we provide evidence that the vitronectin receptor (VNR) alpha v beta 3 is expressed on human NK cells. The presence of this VNR on freshly purified NK cells was demonstrated by flow cytometry analysis, as well as biochemically, after 125I-labeled surface lactoperoxidase labeling and immunoprecipitation. mAbs LM142 and LM609 specific for alpha v and alpha v beta 3, respectively, precipitated a heterodimer of alpha- and beta-chains with approximate molecular masses of 155 and 110 kDa under nonreducing conditions. Under reducing conditions, there was an apparent decrease in the molecular mass of the alpha-chain, which is likely to result from the release of a protein of 20 to 30 kDa linked by internal disulfide bond to the alpha v-chain. Integrin alpha v beta 3 expressed on NK cells became functional, i.e., was able to bind its ligand, vitronectin (VN), only after cellular activation or when costimulation with an additional signal was provided. Thus, NK cells adhered to plastic-immobilized VN only after IL-2 activation, and RGD-containing synthetic peptides or mAbs specific for alpha v beta 3 complex inhibited this binding. To assess the role of the VNR in signal transduction, anti-beta 3 mAb was used to cluster the VNR on NK cells and, thereby, mimic the process that occurs during formation of adhesive contacts. Cross-linking of VNR on fresh NK cells stimulated phosphorylation on tyrosine residues of several intracellular proteins. The major increase in tyrosine phosphorylation was observed in proteins of approximate molecular masses of 75 and 120 kDa. Therefore, signal transduction by the VNR on NK cells induced activation of intracellular protein kinases. Ligand engagement of the VNR on NK cells also costimulated cytokine production and proliferation of NK cells. Binding of NK cells to plastic-immobilized VN served as a costimulus with either anti-Fc gamma RIII or IL-2 to produce IFN-gamma, TNF-alpha, and cell proliferation. Our findings suggest that occupancy and subsequent clustering of VNRs play a role in the activation and function of human NK cells.