N-Glycosylation dictates proper processing of organic anion transporting polypeptide 1B1.
N-Glycosylation dictates proper processing of organic anion transporting polypeptide 1B1.
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N-糖基化决定有机阴离子转运多肽 1B1 的正确加工
DOI：
10.1371/journal.pone.0052563
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Hong M
中科院分区：
文献类型：
--
作者：
Yao J;Hong W;Huang J;Zhan K;Huang H;Hong M
有机阴离子转运多肽（OATPs）是多种药物、外源性物质和毒素吸收、分布、代谢和排泄（ADME）的重要决定因素。位于细胞外环2和5中的推定N-糖基化位点被认为是所有OATP的共同特征，并且已经证明一些成员是糖基化蛋白。然而，实验证据仍然缺乏这样的翻译后修饰如何影响OATP的转运活性，以及在这些转运蛋白中利用了哪些假定的糖基化位点。在本研究中，我们用谷氨酰胺残基取代了可能参与N-糖基化的天冬酰胺残基，并在OATP 1B 1（一种主要在人肝脏中表达的OATP成员）的结构中鉴定了三个糖基化位点（Asn 134、Asn 503和Asn 516）。我们的结果表明，Asn 134和Asn 516在正常条件下用于糖基化;然而，当Asn 134被突变时，503位的额外天冬酰胺参与了糖基化过程。同时用谷氨酰胺替换所有三种天冬酰胺导致蛋白质水平显著降低以及运输活性丧失。进一步的研究表明，糖基化影响转运蛋白的稳定性，未糖基化的突变体被保留在内质网内。
Organic anion transporting polypeptides (OATPs) have been extensively recognized as key determinants of absorption, distribution, metabolism and excretion (ADME) of various drugs, xenobiotics and toxins. Putative N-glycosylation sites located in the extracellular loops 2 and 5 is considered a common feature of all OATPs and some members have been demonstrated to be glycosylated proteins. However, experimental evidence is still lacking on how such a post-translational modification affect the transport activity of OATPs and which of the putative glycosylation sites are utilized in these transporter proteins. In the present study, we substituted asparagine residues that are possibly involved in N-glycosylation with glutamine residues and identified three glycosylation sites (Asn134, Asn503 and Asn516) within the structure of OATP1B1, an OATP member that is mainly expressed in the human liver. Our results showed that Asn134 and Asn516 are used for glycosylation under normal conditions; however, when Asn134 was mutagenized, an additional asparagine at position 503 is involved in the glycosylation process. Simultaneously replacement of all three asparagines with glutamines led to significantly reduced protein level as well as loss of transport activity. Further studies revealed that glycosylation affected stability of the transporter protein and the unglycosylated mutant was retained within endoplasmic reticulum.
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影响因子：
4.8
作者：
Lee, W;Glaeser, H;Kim, RB
通讯作者：
Kim, RB
影响因子：
29.4
作者：
Ho, Richard H.;Tirona, Rommel G.;Kim, Richard B.
通讯作者：
Kim, Richard B.
有机阴离子转运多肽 1B1 跨膜结构域 2 内雌酮 3-硫酸盐转运必需氨基酸的鉴定
影响因子：
3.7
作者：
Li N;Hong W;Huang H;Lu H;Lin G;Hong M
通讯作者：
Hong M
DOI：
10.1152/ajpgi.00584.2007
发表时间：
2008-04-01
影响因子：
4.5
作者：
Wang, Pijun;Hata, Soichiro;Wolkoff, Allan W.
通讯作者：
Wolkoff, Allan W.
影响因子：
2.1
作者：
Mikkaichi, Tsuyoshi;Suzuki, Takehiro;Abe, Takaaki
通讯作者：
Abe, Takaaki