Physiological study of Cl^- channels associated with gastric proton pump and liver multidrug efflux pump

在胃酸分泌机制中，胃质子泵是刺激-分泌耦合的终端靶点。1987年，我们发现Cl^-通道是质子泵功能的一部分；即Cl^-通道和质子泵的两种功能在同一分子中共存。1992年，剑桥大学和牛津大学的研究人员在多药外排泵上发现了类似的发现。在这项资助的第一年，我们建立了模型系统，可视化了多药外排泵的功能，发现环孢素在肝移植中的副作用是由于环孢素抑制了多药外排泵（transplantation, 1993）。在临床剂量下，未发现FK506对外排泵的抑制作用。不可逆抑制剂奥美拉唑和E3810对胃质子泵构象的影响不同(j .生物化学。, 1993)。我们还在胃酸分泌细胞中发现了一种新的Cl^-通道(J.Physiol。, 1993)。在第二年，我们研究了由抑制剂结合的泵的细胞内运输。, 1994)。通过培养单克隆抗体（Biochem.J.）研究了该泵在膜中的c端拓扑结构。, 1994)。胃质子泵的分子结构与结肠质子泵略有不同。我们成功地培养了两种单克隆抗体；一种只与胃泵结合，另一种与两个泵都结合（生物化学）。, 1994)。细胞保护性Cl^-通道的胞内调控机制也被研究（J.Biol.Chem.）。, 1994)。我们还制备了编码胃质子泵α和β亚基的cdna。

Gastric proton pump is the terminal target of the stimulus-secretion coupling in the acid secretory mechanism. In 1987, we found that Cl^- channel was the part of the function of this proton pump ; that is, two functions of the Cl^- channel and the proton pump are coexisted in the same molecule. In 1992, Cambridge and Oxford researchers found a similar finding with the multidrug efflux pump.In the first year of this grant, we established the model system in which the function of multidrug efflux pump was visualized and the side effect of cyclosporin in liver transplantation was found to be due to inhibition of the multidrug efflux pump by cyclosporin (Transplantation, 1993). The inhibition of the efflux pump was not found with FK506 at the clinical dose. The conformation of gastric proton pump was differently affected by omeprazole and E3810 which are irreversible inhibitors (J.Biol.Chem., 1993). We also found a new type of Cl^- channel in the gastric acid secreting cell (J.Physiol., 1993).In the second year, we studied the intracellular transport of the pump bound by the inhibitors (Biochem.Phannacol., 1994). The C-terminal topology of this pump in the membrane was studied by raising a monoclonal antibody (Biochem.J., 1994). The molecular structure of gastric proton pump is slightly different from that of the colonic proton pump. We succeeded to raise two monoclonal antibodies ; one binds only to the gastric pump and the other binds to both pumps (J.Biochem., 1994). The intracellular regulatory mechanism of the cytoprotective Cl^- channel was also studied (J.Biol.Chem., 1994). We also prepared cDNAs which encode alpha and beta subunits of gastric proton pump.