Molecular structure and functional regulation of ATP-binding cassette transporters

ATP结合盒转运蛋白的分子结构和功能调控

基本信息

批准号：
13142208
负责人：
WADA Morimasa
金额：
$ 44.99万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2005
项目状态：
已结题

项目摘要

(1) Mechanism of substrate recognition : By constructing of ABCC1/ABCC2 chimeric proteins and examining their the kinetic properties for LTC_4 transport in inside-out membrane vesicles, we have obtained the results suggesting that Membrane Spanning Domain (MSD)1 are involved in substrate affinity and that the COOH-terminal half is exchangeable between two proteins. Because, basic and/or charged residues in MSD2 and MSD3 but not in MSD1 have been reported repeatedly to be involved in substrate binding, our results shows that portion contributing in substrate affinity would be different from that of substrate binding itself.(2) Sorting mechanisms for intracellular localization : We narrowed down the region participating in determination of apical-basolateral localization to the second membrane spanning domain 2(MSD2)and surrounding region.(3) To evaluate the effect of ABCB1 in intestinal tumorigenesis directly, we generated Abcbla-disrupted mice with an Apc^<min/+> background, an animal model for human familial adenomatous polyposis, and examined whether polyp formation were affected by the absence of functional ABCB1. The number and size of intestinal polyps in Abcbla^<-/->, Apc^<min/+> mice was significantly smaller than the number in Abcbla^<+/+>, Apc^<Min/+> mice. We then analyzed association between genetic variations in the ABCBI gene and cororectal cancer risk. By case-control study using 460 colorectal cancer patients and 783 healthy volunteers, we obtained the results indicating that the cancer risk of individuals who's genetic background is associated with low ABCB1 level is half of the individuals with lower ABCB1 genetic background.

（1）底物识别的机制：通过构建ABCC1/ABCC2嵌合蛋白，并检查其在内部外膜囊泡中LTC_4传输的动力学特性，我们获得了结果，表明膜跨度域（MSD）1涉及底物亲和力和两种蛋白质之间的cooH-terminal-terminal-enteral-tern forte蛋白。 Because, basic and/or charged residues in MSD2 and MSD3 but not in MSD1 have been reported repeatedly to be involved in substrate binding, our results shows that portion contributing in substrate affinity would be different from that of substrate binding itself.(2) Sorting mechanisms for intracellular localization : We narrowed down the region participating in determination of apical-basolateral localization to the second membrane spanning domain 2（MSD2）及周边区域。（3）为了评估ABCB1在直接的肠肿瘤发生中的影响，我们用APC^<min/+>背景生成了ABCBLA破坏的小鼠，这是人类家族性腺瘤息肉的动物模型，并检查了是否缺乏息肉的功能性ABCB1。 Abcbla^< - / - >中肠息肉的数量和大小，Apc^<min/+>小鼠明显小于Abcbla^<+/+>，Apc^<min/+>小鼠的数量。然后，我们分析了ABCBI基因的遗传变异与珊瑚癌风险之间的关联。通过使用460名大肠癌患者和783名健康志愿者的病例对照研究，我们获得了结果，表明遗传背景的个体与低ABCB1水平相关的癌症风险是ABCB1遗传背景较低的个体的一半。