PSD-95 interacts with NBCn1 and enhances channel-like activity without affecting Na/HCO(3) cotransport.
PSD-95 interacts with NBCn1 and enhances channel-like activity without affecting Na/HCO(3) cotransport.
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DOI：
10.1159/000343332
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Choi I
中科院分区：
文献类型：
--
作者：
Lee S;Yang HS;Kim E;Ju EJ;Kwon MH;Dudley RK;Smith Y;Yun CC;Choi I
钠/碳酸氢盐转运蛋白NBCn 1在体内细胞内pH调节和跨上皮HCO 3 −运动中发挥重要作用。NBCn 1还具有与Na/HCO 3共转运不偶联的钠通道样活性。我们以前报道，NBCn 1与突触后密度蛋白PSD-95在大脑中相互作用。在这里，我们阐明了NBCn 1/PSD-95相互作用的结构决定因素和功能后果。在大鼠海马CA 3区神经元中，NBCn 1定位于树突轴和棘的突触后膜，偶尔也定位于突触前膜。含有NBCn 1的C-末端131个氨基酸的GST/NBCn 1融合蛋白从大鼠脑裂解物中拉下PSD-95，而GST/NBCn 1-ΔETSL（最后4个氨基酸缺失）和缺乏相同ETSL的GST/NBCn 2（NCBE）则没有。NBCn 1和PSD-95在HEK 293细胞中共免疫沉淀，并且它们的相互作用不影响PSD-95与NMDA受体NR 2A结合的功效。PSD-95对HEK 293细胞和爪蟾卵母细胞中NBCn 1介导的细胞内pH变化的影响可以忽略不计。然而，PSD-95增加了NBCn 1通道样活性产生的离子电导。这种增加被NBCn 1-ΔETSL或含有NBCn 1最后15个氨基酸的肽消除。我们的数据表明，PSD-95与NBCn 1相互作用，并增加其通道样活性，而对Na/HCO 3共转运的影响可以忽略不计。通道样活性发生通过多聚体NBCn 1蛋白的分子间空腔的可能性进行了讨论。
The sodium/bicarbonate transporter NBCn1 plays an essential role in intracellular pH regulation and transepithelial HCO3− movement in the body. NBCn1 also has sodium channel-like activity uncoupled to Na/HCO3 cotransport. We previously reported that NBCn1 interacts with the postsynaptic density protein PSD-95 in the brain. Here, we elucidated the structural determinant and functional consequence of NBCn1/PSD-95 interaction. In rat hippocampal CA3 neurons, NBCn1 was localized to the postsynaptic membranes of both dendritic shafts and spines and occasionally to the presynaptic membranes. A GST/NBCn1 fusion protein containing the C-terminal 131 amino acids of NBCn1 pulled down PSD-95 from rat brain lysates, whereas GST/NBCn1-ΔETSL (deletion of the last four amino acids) and GST/NBCn2 (NCBE) lacking the same ETSL did not. NBCn1 and PSD-95 were coimmunoprecipitated in HEK 293 cells, and their interaction did not affect the efficacy of PSD-95 to bind to the NMDA receptor NR2A. PSD-95 has negligible effects on intracellular pH changes mediated by NBCn1 in HEK 293 cells and Xenopus oocytes. However, PSD-95 increased an ionic conductance produced by NBCn1 channel-like activity. This increase was abolished by NBCn1-ΔETSL or by the peptide containing the last 15 amino acids of NBCn1. Our data suggest that PSD-95 interacts with NBCn1 and increases its channel-like activity while negligibly affecting Na/HCO3 cotransport. The possibility that the channel-like activity occurs via an intermolecular cavity of multimeric NBCn1 proteins is discussed.
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DOI：
10.1111/j.1460-9568.2008.06611.x
发表时间：
2009-02
期刊：
The European journal of neuroscience
影响因子：
--
作者：
Cooper DS;Yang HS;He P;Kim E;Rajbhandari I;Yun CC;Choi I
通讯作者：
Choi I
影响因子：
64.8
作者：
Choi, I;Aalkjaer, C;Boron, WF
通讯作者：
Boron, WF
影响因子：
5.5
作者：
Loiselle, FB;Morgan, PE;Casey, JR
通讯作者：
Casey, JR
影响因子：
37.8
作者：
Boedtkjer, Ebbe;Praetorius, Jeppe;Aalkjaer, Christian
通讯作者：
Aalkjaer, Christian
影响因子：
1.6
作者：
Gill, Harindarpal S.;Boron, Walter F.
通讯作者：
Boron, Walter F.