HIV-1 Tat protein decreases dopamine transporter cell surface expression and vesicular monoamine transporter-2 function in rat striatal synaptosomes.
HIV-1 Tat protein decreases dopamine transporter cell surface expression and vesicular monoamine transporter-2 function in rat striatal synaptosomes.
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DOI：
10.1007/s11481-012-9369-9
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发表时间：
2012-09
影响因子：
6.2
通讯作者：
Zhu, Jun
中科院分区：
文献类型：
--
作者：
Midde, Narasimha M.;Gomez, Adrian M.;Zhu, Jun
多巴胺（DA）转运蛋白（DAT）和水泡单胺转运蛋白（VMAT2）蛋白作为一种生化复合物相互作用，调节多巴胺能神经传递。我们报道了HIV-1Tat1-86降低了大鼠纹状体中特定的[3H]DA摄取和[3H]WIN 35,428结合位点，而没有改变总DAT免疫反应性。本研究确定了Tat对DAT磷酸化和转运以及水泡[3H]DA摄取的影响。蛋白激酶C （PKC）抑制剂双吲哚酰马来酰亚胺I（1µM）预先孵育大鼠纹状体突触体，完全阻断Tat1-86诱导的[3H]DA摄取减少，表明Tat通过PKC依赖机制调节DAT功能。在突触体暴露于Tat1-86（1µM）后，相对于对照组，质膜富集部分（P3）的DAT免疫反应性降低，囊泡富集部分（P4）的DAT免疫反应性升高，而突触体总部分（P2）没有变化，这表明tat诱导的DA摄取抑制可归因于DAT内化。虽然DAT和VMAT2蛋白都是调控突触和细胞质中DA配置所必需的，但Tat分别抑制了[3H]DA进入囊泡（P4）和突触体（P2）的特异性摄取35%和26%，推断Tat在VMAT2蛋白中的抑制作用比DAT蛋白更深远。综上所述，目前的研究表明Tat通过PKC和运输依赖机制抑制DAT功能，并且Tat通过调节DAT和VMAT2蛋白影响多巴胺能张力。这些发现为理解HIV-1病毒蛋白诱导的hiv感染患者DA神经传递功能障碍的药理学机制提供了新的见解。
The dopamine (DA) transporter (DAT) and vesicular monoamine transporter (VMAT2) proteins interact as a biochemical complex to regulate dopaminergic neurotransmission. We have reported that HIV-1Tat1–86 decreases the specific [3H]DA uptake and [3H]WIN 35,428 binding sites without a change in total DAT immunoreactivity in rat striatum. The present study determined the effects of Tat on DAT phosphorylation and trafficking, and vesicular [3H]DA uptake. Pre-incubation of rat striatal synaptosomes with the protein kinase C (PKC) inhibitor bisindolylmaleimide I (1 µM) completely blocked Tat1–86 -induced reduction of [3H]DA uptake, indicating that Tat regulates DAT function through a PKC-dependent mechanism. After exposure of synaptosomes to Tat1–86 (1 µM), DAT immunoreactivity was decreased in plasma membrane enriched fractions (P3) and increased in vesicle-enriched fractions (P4) relative to controls without change in total synaptosomal fractions (P2), suggesting that Tat-induced inhibition of DA uptake is attributable to DAT internalization. Although both DAT and VMAT2 proteins are essential for the regulation of DA disposition in synapse and cytosol, Tat inhibited the specific [3H]DA uptake into vesicles (P4) and synaptosomes (P2) by 35% and 26%, respectively, inferring that the inhibitory effect of Tat was more profound in VMAT2 protein than in DAT protein. Taken together, the current study reveals that Tat inhibits DAT function through a PKC and trafficking-dependent mechanism and that Tat impacts the dopaminergic tone by regulating both DAT and VMAT2 proteins. These findings provide new insight into understanding the pharmacological mechanisms of HIV-1 viral protein-induced dysfunction of DA neurotransmission in HIV-infected patients.
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影响因子：
11.2
作者：
Ernst, Thomas;Yakupov, Renat;Nakama, Helenna;Crocket, Grace;Cole, Michael;Watters, Michael;Ricardo-Dukelow, Mary Lynn;Chang, Linda
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影响因子：
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作者：
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