EXPRESSION CLONING AND CHARACTERIZATION OF THE CANINE PARIETAL-CELL GASTRIN RECEPTOR
EXPRESSION CLONING AND CHARACTERIZATION OF THE CANINE PARIETAL-CELL GASTRIN RECEPTOR
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DOI：
10.1073/pnas.89.8.3605
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发表时间：
1992-04-15
影响因子：
11.1
通讯作者：
BEINBORN, M
中科院分区：
文献类型：
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作者：
KOPIN, AS;LEE, YM;BEINBORN, M
胃泌素是胃壁细胞分泌酸的重要刺激物，并且在结构上与肽激素胆囊收缩素（CCK）相关。壁细胞胃泌素受体的药理学特性与脑中主要的CCK受体CCK-B非常相似。到目前为止，胃泌素和CCK-B受体都没有被克隆，这使得很难确定这两种受体是否不同。我们已经分离出一个克隆编码犬胃泌素受体筛选壁细胞cDNA表达文库，使用放射性配体结合策略。核苷酸序列分析显示，一个开放的阅读框架编码一个453个氨基酸的蛋白质与7个假定的疏水跨膜结构域和显着的同源性与β-肾上腺素能家族的G蛋白偶联受体的成员。表达的重组受体显示出与犬壁细胞受体相同的胃泌素/CCK激动剂和拮抗剂的结合特异性。在表达克隆受体的COS-7细胞中，胃泌素刺激的磷脂酰肌醇水解和细胞内Ca 2+动员表明通过磷脂酶C的第二信使信号传导。COS-7细胞中表达的受体的亲和标记揭示了与天然壁细胞受体大小相同的蛋白质。在壁细胞和大脑皮层中通过高严格RNA印迹分析鉴定胃泌素受体转录物，表明胃泌素和CCK-B受体是高度同源或相同的。
Gastrin is an important stimulant of acid secretion by gastric parietal cells and is structurally related to the peptide hormone cholecystokinin (CCK). The pharmacologic properties of the parietal cell gastrin receptor are very similar to the predominant CCK receptor in the brain, CCK-B. Neither the gastrin nor the CCK-B receptor have been cloned thus far, making it difficult to resolve whether these two receptors are distinct. We have isolated a clone encoding the canine gastrin receptor by screening a parietal cell cDNA expression library using a radioligand-binding strategy. Nucleotide sequence analysis revealed an open reading frame encoding a 453-amino acid protein with seven putative hydrophobic transmembrane domains and significant homology with members of the beta-adrenergic family of G protein-coupled receptors. The expressed recombinant receptor shows the same binding specificity for gastrin/CCK agonists and antagonists as the canine parietal cell receptor. Gastrin-stimulated phosphatidylinositol hydrolysis and intracellular Ca2+ mobilization in COS-7 cells expressing the cloned receptor suggest second-messenger signaling through phospholipase C. Affinity labeling of the expressed receptor in COS-7 cells revealed a protein identical in size to the native parietal cell receptor. Gastrin receptor transcripts were identified by high-stringency RNA blot analysis in both parietal cells and cerebral cortex, suggesting that the gastrin and CCK-B receptors are either highly homologous or identical.