The role of N-glycosylation in the stability, trafficking and GABA-uptake of GABA-transporter 1 - Terminal N-glycans facilitate efficient GABA-uptake activity of the GABA transporter
文献类型:期刊论文
作者 | Cai, GQ; Salonikidis, PS; Fei, J; Schwarz, W; Schulein, R; Reutter, W; Fan, H |
刊名 | FEBS JOURNAL
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出版日期 | 2005 |
卷号 | 272期号:7页码:1625-1638 |
关键词 | GABA transporter N-glycosylation N-glycan trimming membrane trafficking patch-clamp |
通讯作者 | Fan, H (reprint author), Charite Univ Med Berlin, Inst Mol Biol & Biochem, CBF, Campus Bejamin Franklin,Arnimallee 22, D-14195 Berlin, Germany.,hua.fan@charite.de |
英文摘要 | Neurotransmitter transporters play a major role in achieving low concentrations of their respective transmitter in the synaptic cleft. The GABA transporter GAT1 belongs to the family of Na(+)- and Cl(-)-coupled transport proteins which possess 12 putative transmembrane domains and three N-glycosylation sites in the extracellular loop between transmembrane domain 3 and 4. To study the significance of N-glycosylation, green fluorescence protein (GFP)-tagged wild type GAT1 (NNN) and N-glycosylation defective mutants (DDQ, DGN, DDN and DDG) were expressed in CHO cells. Compared with the wild type, all N-glycosylation mutants showed strongly reduced protein stability and trafficking to the plasma membrane, which however were not affected by 1-deoxymannojirimycin (dMM). This indicates that N-glycosylation, but not terminal trimming of the N-glycans is involved in the attainment of a correctly folded and stable conformation of GAT1. All N-glycosylation mutants were expressed on the plasma membrane, but they displayed markedly reduced GABA-uptake activity. Also, inhibition of oligosaccharide processing by dMM led to reduction of this activity. Further experiments showed that both N-glycosylation mutations and dMM reduced the V(max) value, while not increasing the K(m) value for GABA uptake. Electrical measurements revealed that the reduced transport activity can be partially attributed to a reduced apparent affinity for extracellular Na(+) and slowed kinetics of the transport cycle. This indicates that N-glycans, in particular their terminal trimming, are important for the GABA-uptake activity of GAT1. They play a regulatory role in the GABA translocation by affecting the affinity and the reaction steps associated with the sodium ion binding. |
学科主题 | Biochemistry & Molecular Biology |
类目[WOS] | Biochemistry & Molecular Biology |
关键词[WOS] | AMINOBUTYRIC-ACID TRANSPORTER ; NEUROTRANSMITTER TRANSPORTERS ; RAT-BRAIN ; ENDOPLASMIC-RETICULUM ; CYSTEINE RESIDUES ; MEMBRANE-PROTEINS ; LIVING CELLS ; SIALIC-ACID ; OLIGOSACCHARIDES ; SODIUM |
收录类别 | SCI |
语种 | 英语 |
WOS记录号 | WOS:000227864800007 |
版本 | 出版稿 |
源URL | [http://202.127.25.143/handle/331003/1941] ![]() |
专题 | 上海生化细胞研究所_上海生科院生化细胞研究所 |
推荐引用方式 GB/T 7714 | Cai, GQ,Salonikidis, PS,Fei, J,et al. The role of N-glycosylation in the stability, trafficking and GABA-uptake of GABA-transporter 1 - Terminal N-glycans facilitate efficient GABA-uptake activity of the GABA transporter[J]. FEBS JOURNAL,2005,272(7):1625-1638. |
APA | Cai, GQ.,Salonikidis, PS.,Fei, J.,Schwarz, W.,Schulein, R.,...&Fan, H.(2005).The role of N-glycosylation in the stability, trafficking and GABA-uptake of GABA-transporter 1 - Terminal N-glycans facilitate efficient GABA-uptake activity of the GABA transporter.FEBS JOURNAL,272(7),1625-1638. |
MLA | Cai, GQ,et al."The role of N-glycosylation in the stability, trafficking and GABA-uptake of GABA-transporter 1 - Terminal N-glycans facilitate efficient GABA-uptake activity of the GABA transporter".FEBS JOURNAL 272.7(2005):1625-1638. |
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