CHARACTERIZATION OF MAMMALIAN ADP-RIBOSYLTRANSFERASES

单腺苷二磷酸核糖基化是一种翻译后 NAD中含有ADP-核糖部分的蛋白质的修饰 转移到蛋白质上并对某些物质的毒性负责 细菌毒素(如霍乱毒素、百日咳毒素)。类似于 霍乱毒素，某些哺乳动物的ADP-核糖基转移酶 具体使用精氨酸胍基团作为ADP-核糖 接受者。五种哺乳动物NAD：精氨酸ADP-核糖基转移酶 (ART)是从不同组织中克隆的。Art1蛋白是 显示为细胞表面蛋白，通过一种 糖基磷脂酰肌醇(GPI)锚定。此时会出现转移酶 在哺乳动物组织中选择性表达。ART-1可在 骨骼肌、心肌和淋巴样细胞，ART-2 淋巴细胞，ART-4存在于脾，ART-5存在于睾丸。鉴于 ARTS在参与免疫调节的组织中的表达 检查ARTS是否可能在肺上皮细胞中表达 细胞。人呼吸道上皮细胞的分离 支气管肺泡灌洗和支气管刷洗。通过现场分析 Northern印迹法检测到Art1在呼吸道上皮细胞中的表达 细胞。正如预期的那样，GPI锚定蛋白的定位 纤毛上皮细胞顶面的Art1 用多克隆抗Art1抗体和 通过治疗后这种免疫反应性的丧失来确认 磷脂酰肌醇特异性磷脂酶C(PI-PLC)，它 选择性地切割GPI锚定并从 质膜。通过与特异的ART3和ART3进行原位杂交 ART4寡核苷酸，RT6的另外两个成员 在上皮细胞中也可见超家族。在协议中 根据这些发现，ART3和ART4mRNAs被鉴定为 人气管组织Poly(A)+RNA的RT-PCR检测有趣的是，这些 蛋白质似乎优先定位于呼吸道。 上皮组织。Rt6这些成员的定位表达 人肺上皮细胞中的超家族可能反映了 呼吸道内免疫反应过程中的细胞-细胞信号。

Mono-ADP-ribosylation is a post-translational modification of proteins in which the ADP-ribose moiety of NAD is transferred to proteins and is responsible for the toxicity of some bacterial toxins (e.g., cholera toxin, pertussis toxin). Similar to cholera toxin, some mammalian ADP-ribosyltransferases specifically use the guanidino group of arginine as an ADP-ribose acceptor. Five mammalian NAD: arginine ADP-ribosyltransferases (ART) were cloned from various tissues. The ART1 proteins were shown to be cell surface proteins, linked through a glycosylphosphatidylinositol (GPI) anchor. The transferases appear to be selectively expressed in mammalian tissues. ART-1 is found in skeletal and cardiac muscle and lymphoid cells, ART-2 in lymphocytes, ART-4 in spleen and ART-5 in testis. In view of the expression of ARTs in tissues involved in immunoregulation, we examined whether ARTs might be expressed in pulmonary epithelial cells. Human airway epithelial cells were isolated by bronchoalveolar lavage and bronchial brushing. By in situ analysis and Northern blot, ART1 mRNA was identified in airway epithelial cells. As expected for GPI-anchored proteins, the localization of ART1 at the apical surface of ciliated epithelial cells was demonstrated by staining with polyclonal anti-ART1 antibody and confirmed by loss of this immunoreactivity after treatment with phosphatidylinositol-specific phospholipase C(PI-PLC), which selectively cleaves GPI-anchors and releases proteins from the plasma membrane. By in situ hybridization with specific ART3 and ART4 oligonucleotides, two additional members of the RT6 superfamily were also demonstrated in epithelial cells. In agreement with these findings, ART3 and ART4 mRNAs were identified by RT-PCR of poly(A)+RNA from human trachea. Interestingly, these proteins appeared to be preferentially localized to the airway epithelium. The localized expression of these members of the RT6 superfamily in human pulmonary epithelial cells may reflect a role in cell-cell signaling during immune responses within the airway.