The ANKK1 Protein Associated with Addictions has Nuclear and Cytoplasmic Localization and Shows a Differential Response of Ala239Thr to Apomorphine
The ANKK1 Protein Associated with Addictions has Nuclear and Cytoplasmic Localization and Shows a Differential Response of Ala239Thr to Apomorphine
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DOI：
10.1007/s12640-010-9219-6
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发表时间：
2011-07-01
影响因子：
3.7
通讯作者：
Hoenicka, J.
中科院分区：
文献类型：
--
作者：
Garrido, E.;Palomo, T.;Hoenicka, J.
TaqIA单核苷酸多态性（SNP）是成瘾中研究最广泛的遗传多态性，位于编码RIP激酶ANKK 1的基因上，靠近多巴胺受体D2的基因。TaqIA SNP与SNP rs7118900处于强连锁不平衡，其将ANKK 1蛋白中第239位的丙氨酸改变为苏氨酸（Ala 239/A2; Thr 239/A1）。计算机模拟分析预测，这种多态性取代在ANKK 1的激酶结构域中产生了额外的磷酸化位点。为了研究ANKK 1对TaqIA相关表型的病理生理学的贡献，我们分析了用GFP标记的人ANKK 1-激酶（Ala 239）和ANKK 1-激酶（Thr 239）变体转染的HEK 293 T细胞。我们观察到ANKK 1-激酶位于细胞核和细胞质中，这表明存在这种假定的信号转导物的核质穿梭。此外，我们发现，Ala 239 Thr ANKK 1-激酶多态性表现出强烈的表达差异，在细胞核和细胞质中的基础水平，当刺激多巴胺受体激动剂阿扑吗啡。具体而言，ANKK 1-激酶（Thr 239）变体显示出最高水平的基础蛋白表达，而ANKK 1-激酶（Ala 239）则低0.64倍。阿扑吗啡处理后，ANKK 1-激酶（Ala 239）显示蛋白水平增加2.4倍，而ANKK 1-激酶（Thr 239）则减少0.67倍。因此，在这里，我们提供了第一个证据的功能ANKK 1的差异是由TaqIA标记，并可能与成瘾的脆弱性。
The TaqIA single-nucleotide polymorphism (SNP), which is the most widely studied genetic polymorphism in addictions, is located at the gene that encodes the RIP kinase ANKK1 near the gene for dopamine receptor D2. The TaqIA SNP is in strong linkage disequilibrium with the SNP rs7118900, which changes the alanine at position 239 to threonine in the ANKK1 protein (Ala239/A2; Thr239/A1). In silico analysis has predicted that this polymorphic substitution creates an additional phosphorylation site in the kinase domain of ANKK1. To investigate the contribution of ANKK1 to the pathophysiology of TaqIA-associated phenotypes, we analyzed transfected HEK293T cells with the human ANKK1-kinase(Ala239) and ANKK1-kinase(Thr239) variants tagged with GFP. We observed that the ANKK1-kinase is located in both the nucleus and the cytoplasm, suggesting that there is nucleocytoplasmic shuttling of this putative signal transducer. In addition, we found that the Ala239Thr ANKK1-kinase polymorphism exhibited strong expression differences in both the nucleus and the cytoplasm at basal level and when stimulated with the dopamine agonist apomorphine. Specifically, the ANKK1-kinase(Thr239) variant showed the highest level of basal protein expression, while ANKK1-kinase(Ala239) was 0.64-fold lower. After treatment with apomorphine, ANKK1-kinase(Ala239) showed a 2.4-fold increment in protein levels, whereas a 0.67-fold reduction was observed in ANKK1-kinase(Thr239). Thus, here we provide the first evidence of functional ANKK1 differences that are marked by TaqIA and could be associated with vulnerability to addiction.