Regulation of dopamine transporter trafficking by intracellular amphetamine
Regulation of dopamine transporter trafficking by intracellular amphetamine
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DOI：
10.1124/mol.106.023952
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发表时间：
2006-08-01
影响因子：
3.6
通讯作者：
Galli, Aurelio
中科院分区：
文献类型：
--
作者：
Kahlig, Kristopher M.;Lute, Brandon J.;Galli, Aurelio
多巴胺（DA）转运蛋白（DAT）介导释放的DA的清除。DAT是负责精神兴奋剂安非他明（AMPH）的奖励特性和滥用潜力的主要分子靶点。AMPH已被证明可以减少细胞表面DAT的数量，这种AMPH诱导的细胞表面DAT重新分布可能导致DA稳态的长期变化。AMPH诱导运输的分子机制尚不清楚。由于AMPH是一种底物，我们不知道细胞外AMPH是否通过与DAT的相互作用刺激运输，并随后改变DAT功能，从而触发细胞内信号传导，或者AMPH是否必须被运输，然后在细胞内发挥作用。与我们先前的研究一致，细胞外AMPH引起野生型人DAT（WT-hDAT）的胞质再分布。然而，在摄取受损的hDAT（Y335 A-hDAT）中，AMPH并不诱导胞质再分布，但仍与AMPH结合。二价阳离子锌（Zn 2+）抑制WT-hDAT活性，但其恢复Y335 A-hDAT摄取。Zn ~（2+）和AMPH的联合给药持续降低WT-hDAT的运输，但刺激Y335 A-hDAT的胞质再分布。此外，直接细胞内应用AMPH，通过全细胞贴片移液管，刺激贩运的Y335 A-hDAT。两者合计，这些数据表明，DAT运输周期是不需要的AMPH诱导的下调和细胞内AMPH的增加是DAT再分配的重要组成部分。
The dopamine (DA) transporter (DAT) mediates the removal of released DA. DAT is the major molecular target responsible for the rewarding properties and abuse potential of the psycho-stimulant amphetamine (AMPH). AMPH has been shown to reduce the number of DATs at the cell surface, and this AMPH-induced cell surface DAT redistribution may result in long-lasting changes in DA homeostasis. The molecular mechanism by which AMPH induces trafficking is not clear. Because AMPH is a substrate, we do not know whether extracellular AMPH stimulates trafficking through its interaction with DAT and subsequent alteration in DAT function, thereby triggering intracellular signaling or whether AMPH must be transported and then act intracellularly. In agreement with our previous studies, extracellular AMPH caused cytosolic redistribution of the wildtype human DAT (WT-hDAT). However, AMPH did not induce cytosolic redistribution in an uptake-impaired hDAT (Y335A-hDAT) that still binds AMPH. The divalent cation zinc (Zn2+) inhibits WT-hDAT activity, but it restores Y335A-hDAT uptake. Coadministration of Zn2+ and AMPH consistently reduced WT-hDAT trafficking but stimulated cytosolic redistribution of Y335A-hDAT. Furthermore, direct intracellular application of AMPH, via a whole-cell patch pipette, stimulated the trafficking of Y335A-hDAT. Taken together, these data suggest that the DAT transport cycle is not required for AMPH-induced down-regulation and that an increase of intracellular AMPH is an essential component of DAT redistribution.