Localization and genomic organization of a new hepatocellular organic anion transporting polypeptide
Localization and genomic organization of a new hepatocellular organic anion transporting polypeptide
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DOI：
10.1074/jbc.m001448200
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发表时间：
2000-07-28
影响因子：
4.8
通讯作者：
Keppler, D
中科院分区：
文献类型：
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作者：
König, J;Cui, YH;Keppler, D
基于与人有机阴离子转运多肽2（OATPB; SLC 21 A6）的序列同源性，我们克隆了溶质载体SLC 21 A超家族的新成员，称为OATP 8（SLC 21 A8）。经北方印迹分析，OATP 8基因仅在人肝脏中表达。含有编码人OATP 1（SLC 21 A3）、OATP 2（SLC 21 A6）和OATP 8（SLC 21 AS）的基因的粘粒克隆用于建立其基因组结构。所有三个基因含有14个外显子，13个相同的剪接位点时，转移到氨基酸序列。OATP 8羧基端抗体定位于人肝细胞基底外侧膜，重组糖蛋白在MDCK Ⅱ细胞中表达，定位于侧膜。人OATP转运的有机阴离子8包括磺溴酞（Km为3.3 μ M）和17 β-葡萄糖醛酸雌二醇（Km为5.4 μ M）。几种胆汁盐不是底物。因此，人OATPS是基底外侧肝细胞膜中的一种新摄取转运蛋白，与OATP 2相比具有重叠但不同的底物特异性，OATP 2定位于相同的膜结构域。
Based on sequence homology to the human organic anion transporting polypeptide 2 (OATPB; SLC21A6), we cloned a new member of the SLC21A superfamily of solute carriers, termed OATP8 (SLC21A8). The protein of 702 amino acids showed an amino acid identity of 80% with human OATPS, Based on Northern blotting, the expression of OATP8 was restricted to human liver. Cosmid clones containing the genes encoding human OATP1 (SLC21A3), OATP2 (SLC21A6), and OATP8 (SLC21AS) served to establish their genomic organization. All three genes contained 14 exons with 13 identical splice sites when transferred to the amino acid sequence. An antibody raised against the carboxyl terminus localized OATP8 to the basolateral membrane of human hepatocytes and the recombinant glyeoprotein, expressed in MDCKII cells, to the lateral membrane, Transport properties of OATP8 were studied in stably transfected MDCKII and HEH293 cells. Organic anions transported by human OATP8 included sulfobromophthalein, with a K-m of 3.3 mu M, and17 beta-glucuronosyl estradiol, with a K-m of 5.4 mu M Several bile salts were not substrates. Thus, human OATPS is a new uptake transporter in the basolateral hepatocyte membrane with an overlapping but distinct substrate specificity as compared with OATP2, which is localized to the same membrane domain.