SOLUBILIZATION AND RECONSTITUTION OF GAMMA-AMINOBUTYRIC ACID TRANSPORTER FROM RAT-BRAIN
SOLUBILIZATION AND RECONSTITUTION OF GAMMA-AMINOBUTYRIC ACID TRANSPORTER FROM RAT-BRAIN
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DOI：
10.1016/0014-5793(78)80519-5
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发表时间：
1978-01-01
期刊：
影响因子：
3.5
通讯作者：
KANNER, BI
中科院分区：
文献类型：
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作者：
KANNER, BI
在突触体等脑制剂中已经发现了各种神经递质的高亲和力、钠依赖性、主动转运系统[1 -5]。这些系统与突触后受体的递质作用终止有关[11]，也与维持神经元中递质的恒定水平有关[10]。最近，这些神经递质之一的氨基丁酸（GABA）的主动运输模式在突触体[7]的膜泡中被研究。离子梯度是这种主动积累的直接驱动力，这一观点得到了膜囊更直接的支持。这一过程完全依赖于外部的钠离子和氯离子，并且这两种梯度（out> in）都可以驱动GABA的积累。对氯离子梯度的依赖不能仅仅用过程的电原性来解释。因此，氯离子可能与钠离子和GABA一起向内移位，或者这些阴离子是使载体达到GABA移位所需的构象所必需的。要在这些可能性之间作出决定，就需要进行直接通量实验。这些实验可能只有在含有高度纯化的GABA转运体制剂的重组蛋白脂质体中才会成功，这些蛋白脂质体预计具有非常低的氯离子渗透率。此外，利用这种重组系统对GABA易位机制的其他方面的研究也将具有重要意义。这篇报道描述了GABA转运体的溶解和它的功能整合到
High affinity, sodium-dependent, active transport systems for various neurotransmitters have been detected in brain preparations such as synaptosomes [l-5]. These systems have been implicated in termination of transmitter action on post-synaptic receptors [11 as well as in maintaining constant levels of transmitters in the neurons [6]. Recently, the mode of active transport of one of these neurotransmitters, y-aminobutyric acid (GABA), has been investigated in membrane vesicles derived from synaptosomes [7]. The idea that ion gradients are the immediate driving force for this active accumulation [5], has been supported more directly using these membrane vesicles [7]. The process is absolutely dependent on both external sodium and chloride ions, and both gradients (out> in) can drive GABA accumulation. The dependency on the chloride ion gradient cannot be explained by the electrogenicity of the process alone. Thus, either chloride ions may be translocated inward together with sodium ions and GABA, or these anions are necessary to bring the carrier to the conformation required for GABA translocation. Direct flux experiments are required to decide between these possibilities. These experiments probably will be successful only in reconstituted proteoliposomes containing highly purified GABA transporter preparations, which are expected to have a very low chloride permeabihty. In addition, the use of such a reconstituted system will be important for the study of other aspects of the mechanism of GABA translocation. This report describes the solubilisation of the GABA transporter and its functional incorporation into