Mechanism of Action of Atrial Natriuretic Peptide (ANP)

为了了解心房利钠肽（ANP）的分子作用机制，对介导ANP生理作用的受体进行了分离、表征、分类和细胞水平可视化。测定了C型ANP受体的基因结构。1)纯化和性质：C型ANP受体通过亲和层析从牛肺质膜中纯化得到，是由两个70 kda亚基组成的二硫化物连接的同型二聚体。测定纯化蛋白的色氨酸片段的氨基酸序列。2)利用无细胞翻译系统研究了C型ANP受体的生物合成过程；糖肽酶酶切结果显示，成熟受体每70 kda亚基含有3个N -连接的低聚糖。受体的配体结合活性不受去糖基化的影响。3)免疫组化定位：在肾脏和肺中，受体分别定位于肾小球和上皮细胞。肾小球的定位很好地解释了ANP对肾小球滤过率的刺激作用。4)作用机制：通过特异性抗受体抗血清和辐射失活分析ANP对颗粒鸟苷酸环化酶的激活作用，提出了一种新的解离激活机制。5)通过对AN受体在不同靶组织上的生化、免疫化学和药理学表征，揭示了AN受体亚型的组织特异性分布。令人惊讶的是，用培养的血管细胞进行的类似分析显示，在体外培养时，动脉细胞开始表达不同的亚型，这种有趣的现象被称为“亚型转换”。6) A型ANP受体的亚基结构：单链受体亚型称为A型受体，在牛肾上腺带肾小球细胞中以四聚体的形式存在。7)测定了牛C型ANP受体qe的结构，并与大鼠A型受体进行了比较。C型受体基因异常长，跨越超过85 kb。有趣的特征是，基因组结构（外显子-内含子组织）模仿受体的结构域结构，内含子的定位与A型和C型受体基因非常相似。少

To understand the molecular mechanism of action of atrial natriuretic peptide (ANP), the receptors mediating the physiological actions of ANP have been isolated, characterized, classified into subtypes, and visualized at the cellular level. The gene structure of the type C ANP receptor was also determined. 1) Purification and Properties : type C ANP receptor was purified from bovine lung plasma membranes by affinity chromatography and shown to be a disulfide-linked homodimer consisting of two 70-kDa subunits. Amino acid sequences of tryptic fragments of the purified protein were determined. 2) Biosynthetic process of the type C ANP receptor was examined using a cell-free translation system ; glycopeptidase digestion revealed that the mature receptor has three N -linked oligosaccharides per 70-kDa subunit. The ligand-binding activity of the receptor was not affected by the deglycosylation. 3) Immunohistochemical localization : in the kidney and lung, the receptor was localized to the po … More docytes of the glomeruli and the epithelial cells, respectively. The glomerular localization explains well the stimulatory effect of ANP on glomerular filtration rate. 4) Mechanism of action : activation by ANP of particulate guanylate cyclase was analyzed by using a specific antireceptor antiserum and by radiation inactivation, and a new dissociative activation mechanism has been proposed. 5) Tissue-specific distribution of AN receptor subtypes was revealed by biochemical, immunochemical, and phrmacological characterization of the receptors on various target tissues. Surprisingly, similar analysis using cultured vascular cells revealed that arterial cells begin to express different subtypes when cultured in vitro and this interesting phenomenon was termed "subtype switching". 6) Subunit structure of the type A ANP receptor : the single chain receptor subtype, termed type A receptor, was shown to be present as a tetramer in the bovine adreal zona glomerulosa cells. 7) The structure of the bovine type C ANP receptor qe was determined and compared with that of the rat type A receptor. The type C receptor gene was unusually long, spanning more than 85 kb. Interesting features are that the genomic structure (exon-intron organization) mimics the domain structure of the receptor and intron positioning is very similar bype A and C receptor genes. Less