Functional characterization of human organic cation transporter OCTN1 single nucleotide polymorphisms in the Japanese population
Functional characterization of human organic cation transporter OCTN1 single nucleotide polymorphisms in the Japanese population
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DOI：
10.1002/jps.20190
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发表时间：
2004-12-01
影响因子：
3.8
通讯作者：
Tsuji, A
中科院分区：
文献类型：
--
作者：
Kawasaki, Y;Kato, Y;Tsuji, A
有机阳离子转运蛋白OCTN 1（SLC 22 A4）广泛表达，在肾脏、气管、骨髓和胎肝中有强表达，它以pH依赖性方式介导有机阳离子的转运。最近的研究已经确定了日本人群中OCTN 1的单核苷酸多态性（SNP）。外显子区域存在的两个SNPs c1063 t和g1531 a分别引起氨基酸突变Thr 3061 le（T306 I）和Gly 462 Glu（G462 E）。我们研究了这些SNPs对OCTN 1细胞内定位、蛋白表达和转运活性的影响。免疫细胞化学分析显示，在用OCTN 1或其SNP等位基因变体的表达质粒DNA瞬时转染的HEK 293细胞的细胞膜中，OCTN 1具有相似的定位。T3061摄取四乙基铵（TEA）的Km和V-max值与野生型相似，即使将V-max值针对OCTN 1蛋白的表达水平进行归一化。相反，G462 E具有几乎可以忽略的转运活性，尽管G462 E的蛋白表达水平与野生型相当。我们的结论是，导致单氨基酸突变T3061的SNP不影响TEA转运活性，而突变G462 E废除了TEA转运活性，可能影响OCTN 1的生理功能和/或其底物的药理学特性。(C)2004 Wiley-Liss，Inc.和美国药剂师协会
The organic cation transporter OCTN1 (SLC22A4) is expressed ubiquitously, with strong expression in kidney, trachea, bone marrow, and fetal liver, and it mediates transport of organic cations in a pH-dependent manner. Recent studies have identified single nucleotide polymorphisms (SNPs) of OCTN1 in the Japanese population. Two SNPs present in the exon regions, c1063t and g1531a, cause amino acid mutation, Thr3061le (T306I) and GIy462Glu (G462E), respectively. We examined the influence of these SNPs on the intracellular localization, protein expression, and transport activity of OCTN1. Immunocytochemical analysis showed similar localizations of OCTN1 in cellular membranes of HEK293 cells transiently transfected with an expression plasmid DNA for OCTN1 or its SNP allelic variants. The K-m and V-max values for tetraethylarnmonium (TEA) uptake by T3061 were similar to those of the wild-type even when the V-max value was normalized for the expression level of OCTN1 protein. In contrast, G462E had almost negligible transport activity, although the protein expression level of G462E was equivalent to that of the wild-type. We conclude that the SNP that causes the single amino acid mutation T3061 does not affect TEA transport activity, whereas the mutation G462E abrogates the TEA transport activity, presumably affecting the physiological function of OCTN1 and/or the pharmacological characteristics of its substrates. (C) 2004 Wiley-Liss, Inc. and the American Pharmacists Association.