Di Paolo E, De Neef P, Moguilevsky N, Petry H, Cnudde J, Bollen A, Waelbroeck M, Robberecht P
Department of Biochemistry, Faculty of Medicine, Brussels, Belgium.
Pancreas. 1999 Jul;19(1):51-5.
A secretin receptor was cloned from a commercial human pancreatic complementary DNA (cDNA) bank. The amino acid sequence deduced from the nucleotide sequence differed slightly from the three different sequences previously published, suggesting a genetic polymorphism of the human receptor. The binding properties of the receptor were evaluated by testing natural secretin, related peptides, and synthetic analogs or fragments on membranes of Chinese hamster ovary (CHO) cells expressing the receptor after transfection. The second-messenger coupling was evaluated by adenylate cyclase measurement. The human secretin receptor was compared with the rat and the rabbit receptors. In the three animals species, rat and human secretin were equipotent; rabbit secretin was equipotent on human and rabbit secretin receptors and less potent on the rat receptor. Similar data were obtained for the [Arg16]-secretin analog. Deletion of histidine 1 and replacement of aspartate 3 reduced the affinity of the peptides for the three receptors; however, the reduction was more pronounced on rat than on human and rabbit secretin receptors. Finally, the low affinity of the rat and human receptors for vasoactive intestinal peptide (VIP) was identical; the rabbit receptor, however, had a 20-fold higher affinity. Thus the human secretin receptor shows properties of both rat and rabbit receptors. Evaluation of the properties of chimeric receptors will be useful to fit the ligand on the receptors.
从一个商业化的人胰腺互补DNA（cDNA）文库中克隆出了促胰液素受体。从核苷酸序列推导出来的氨基酸序列与之前发表的三种不同序列略有差异，这表明人受体存在基因多态性。通过在转染后表达该受体的中国仓鼠卵巢（CHO）细胞膜上测试天然促胰液素、相关肽以及合成类似物或片段，评估了该受体的结合特性。通过测量腺苷酸环化酶来评估第二信使偶联。将人促胰液素受体与大鼠和兔的受体进行了比较。在这三种动物中，大鼠和人促胰液素具有同等效力；兔促胰液素在人和兔促胰液素受体上具有同等效力，而在大鼠受体上效力较低。对于[Arg16]-促胰液素类似物也获得了类似的数据。组氨酸1的缺失和天冬氨酸3的替换降低了这些肽对三种受体的亲和力；然而，这种降低在大鼠受体上比在人和兔促胰液素受体上更为明显。最后，大鼠和人受体对血管活性肠肽（VIP）的低亲和力是相同的；然而，兔受体的亲和力高20倍。因此，人促胰液素受体兼具大鼠和兔受体的特性。评估嵌合受体的特性将有助于使配体与受体相匹配。
