Coupled and uncoupled proton movement by amino acid transport system N
Coupled and uncoupled proton movement by amino acid transport system N
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DOI：
10.1093/emboj/20.24.7041
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发表时间：
2001-12-17
期刊：
影响因子：
11.4
通讯作者：
Edwards, RH
中科院分区：
文献类型：
--
作者：
Chaudhry, FA;Krizaj, D;Edwards, RH
已经提出系统N转运蛋白SN 1介导维持尿素循环和谷氨酰胺-谷氨酸循环所需的谷氨酰胺从细胞的流出，所述谷氨酰胺-谷氨酸循环再生谷氨酸和γ-氨基丁酸（GABA）用于突触释放。我们现在表明，SN 1也介导了由谷氨酰胺激活的离子电导，并且这种电导对H+具有选择性。虽然SN 1偶联氨基酸摄取H+交换，谷氨酰胺门控的H+电导是不化学计量耦合到运输。因此，质子渗透SN 1耦合和解耦合的氨基酸流量，提供新的机制来调节细胞之间的谷氨酰胺的转移。
The system N transporter SN1 has been proposed to mediate the efflux of glutamine from cells required to sustain the urea cycle and the glutamine-glutamate cycle that regenerates glutamate and gamma -aminobutyric acid (GABA) for synaptic release. We now show that SN1 also mediates an ionic conductance activated by glutamine, and this conductance is selective for H+. Although SN1 couples amino acid uptake to H+ exchange, the glutamine-gated H+ conductance is not stoichiometrically coupled to transport. Protons thus permeate SN1 both coupled to and uncoupled from amino acid flux, providing novel mechanisms to regulate the transfer of glutamine between cells.