Expression of SLC2A9 isoforms in the kidney and their localization in polarized epithelial cells.
Expression of SLC2A9 isoforms in the kidney and their localization in polarized epithelial cells.
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DOI：
10.1371/journal.pone.0084996
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Sakurai H
中科院分区：
文献类型：
--
作者：
Kimura T;Takahashi M;Yan K;Sakurai H
许多全基因组关联研究指出，SLC2A9基因编码一种电压驱动的尿酸转运蛋白SLC2A9/GLUT9(又名：SLC2A9/GLUT9)。URATv1)，作为影响血尿酸水平的基因之一。SLC2A9编码两种剪接变异体：SLC2A9-S(512个氨基酸)和SLC2A9-L(540个氨基酸)，唯一不同的是它们的N端。我们研究了SLC2A9在人肾脏中的异构体特异性定位以及N-末端氨基酸在体外差异分选中的作用。制备了抗SLC2A9的亚型特异性抗体，并对人肾切片进行染色。SLC2A9-S在集合管的顶端表达，而SLC2A9-L在近端小管的基底外侧表达。将GFP融合的SLC2A9在MDCK细胞中表达，并进行细胞内定位观察。SLC2A9-S在根尖膜和基底侧膜均有表达，而SLC2A9-L仅在基底外侧膜表达。虽然SLC2A9-L在第33位和第34位有一个可能的二亮氨酸基序，但该基序的缺失或亮氨酸的替换并不影响其亚细胞定位。当从SLC2A9-S的N端去掉16个氨基酸或从SLC2A9-L的N端去掉25个氨基酸时，它们的排序没有变化。SLC2A9-S的20个氨基酸缺失在细胞内未表达。SLC2A9-L的30多个氨基酸缺失导致在顶膜和基侧膜以及溶酶体中均有表达。当SLC2A9-L中25位和30位氨基酸转变为丙氨酸时，表达谱与野生型相同。SLC2A9-L在人肾近端小管的基底膜上表达，这种异构体可能与尿酸盐的重吸收有关。每种异构体所特有的N-末端氨基酸在蛋白质的稳定和运输中起着重要作用。
Many genome-wide association studies pointed out that SLC2A9 gene, which encodes a voltage-driven urate transporter, SLC2A9/GLUT9 (a.k.a. URATv1), as one of the most influential genes for serum urate levels. SLC2A9 is reported to encode two splice variants: SLC2A9-S (512 amino acids) and SLC2A9-L (540 amino acids), only difference being at their N-termini. We investigated isoform-specific localization of SLC2A9 in the human kidney and role of N-terminal amino acids in differential sorting in vitro. Isoform specific antibodies against SLC2A9 were developed and human kidney sections were stained. SLC2A9-S was expressed in the apical side of the collecting duct while SLC2A9-L was expressed in the basolateral side of the proximal tubule. GFP fused SLC2A9s were expressed in MDCK cells and intracellular localization was observed. SLC2A9-S was expressed at both apical and basolateral membranes, whereas SLC2A9-L was expressed only at the basolateral membrane. Although SLC2A9-L has a putative di-leucine motif at 33th and 34th leucine, deletion of the motif or replacement of leucine did not affect its subcellular localization. When up to 16 amino acids were removed from the N-terminal of SLC2A9-S or when up to 25 amino acids were removed from the N-terminal of SLC2A9-L, there was no change in their sorting. Deletion of 20 amino acids from SLC2A9-S was not expressed in the cell. More than 30 amino acids deletion from SLC2A9-L resulted in expression at both apical and basolateral membranes as well as in the lysosome. When amino acids from 25th and 30th were changed to alanine in SLC2A9-L, expression pattern was the same as wild-type. SLC2A9-L was expressed in the basolateral membrane of kidney proximal tubules in humans and this isoform is likely to responsible for urate reabsorption. N-terminal amino acids unique to each isoform played an important role in protein stability and trafficking.
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影响因子：
64.8
作者：
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通讯作者：
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影响因子：
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作者：
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影响因子：
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通讯作者：
Cheeseman, Chris
影响因子：
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