Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
J Biol Chem
2013 Feb 15;2887:4549-56. doi: 10.1074/jbc.M112.430215.
Show Gene links
Show Anatomy links
Functional defects in the external and internal thin gates of the γ-aminobutyric acid (GABA) transporter GAT-1 can compensate each other.
Ben-Yona A
,
Kanner BI
.
???displayArticle.abstract???
The GABA transporter GAT-1 belongs to the neurotransmitter:sodium:symporters which are crucial for synaptic transmission. GAT-1 mediates electrogenic transport of GABA together with sodium and chloride. Structure-function studies indicate that the bacterial homologue LeuT, which possess extra- and intracellular thin gates, is an excellent model for this class of neurotransmitter transporters. We recently showed that a conserved aspartate residue of GAT-1, Asp-451, whose LeuT equivalent participates in its thin extracellular gate, is functionally irreplaceable in GAT-1. Only the D451E mutant exhibited residual transport activity but with an elevated apparent sodium affinity as a consequence of an increased proportion of outward-facing transporters. Because during transport the opening and closing of external and internal gates should be tightly coupled, we have addressed the question of whether mutations of the intracellular thin gate residues Arg-44 and Asp-410 can compensate for the effects of their extracellular counterparts. Mutation of Asp-410 to glutamate resulted in impaired transport activity and a reduced apparent affinity for sodium. However, the transport activity of the double mutant D410E/D451E was increased by approximately 10-fold of that of each of the single mutants. Similar compensatory effects were also seen when other combinations of intra- and extracellular thin gate mutants were analyzed. Moreover, the introduction of D410E into the D451E background resulted in lower apparent sodium affinity than that of D451E alone. Our results indicate that a functional interaction of the external and internal gates of GAT-1 is essential for transport.
Ben-Yona,
Transmembrane domain 8 of the {gamma}-aminobutyric acid transporter GAT-1 lines a cytoplasmic accessibility pathway into its binding pocket.
2009, Pubmed
Ben-Yona,
Transmembrane domain 8 of the {gamma}-aminobutyric acid transporter GAT-1 lines a cytoplasmic accessibility pathway into its binding pocket.
2009,
Pubmed
Ben-Yona,
A glutamine residue conserved in the neurotransmitter:sodium:symporters is essential for the interaction of chloride with the GABA transporter GAT-1.
2011,
Pubmed
,
Xenbase
Ben-Yona,
An acidic amino acid transmembrane helix 10 residue conserved in the neurotransmitter:sodium:symporters is essential for the formation of the extracellular gate of the γ-aminobutyric acid (GABA) transporter GAT-1.
2012,
Pubmed
,
Xenbase
Bennett,
Mutation of arginine 44 of GAT-1, a (Na(+) + Cl(-))-coupled gamma-aminobutyric acid transporter from rat brain, impairs net flux but not exchange.
2000,
Pubmed
Bennett,
The membrane topology of GAT-1, a (Na+ + Cl-)-coupled gamma-aminobutyric acid transporter from rat brain.
1997,
Pubmed
Bismuth,
Tyrosine 140 of the gamma-aminobutyric acid transporter GAT-1 plays a critical role in neurotransmitter recognition.
1997,
Pubmed
Borre,
Arginine 445 controls the coupling between glutamate and cations in the neuronal transporter EAAC-1.
2004,
Pubmed
Dodd,
Selective amino acid substitutions convert the creatine transporter to a gamma-aminobutyric acid transporter.
2007,
Pubmed
Forrest,
Mechanism for alternating access in neurotransmitter transporters.
2008,
Pubmed
Fuerst,
Eukaryotic transient-expression system based on recombinant vaccinia virus that synthesizes bacteriophage T7 RNA polymerase.
1986,
Pubmed
Golovanevsky,
The reactivity of the gamma-aminobutyric acid transporter GAT-1 toward sulfhydryl reagents is conformationally sensitive. Identification of a major target residue.
1999,
Pubmed
Hilgemann,
GAT1 (GABA:Na+:Cl-) cotransport function. Database reconstruction with an alternating access model.
1999,
Pubmed
,
Xenbase
Kanner,
Sodium-coupled neurotransmitter transporters.
2008,
Pubmed
Kanner,
Transmembrane domain I of the gamma-aminobutyric acid transporter GAT-1 plays a crucial role in the transition between cation leak and transport modes.
2003,
Pubmed
,
Xenbase
Keynan,
Expression of a cloned gamma-aminobutyric acid transporter in mammalian cells.
1992,
Pubmed
,
Xenbase
Kleinberger-Doron,
Identification of tryptophan residues critical for the function and targeting of the gamma-aminobutyric acid transporter (subtype A).
1994,
Pubmed
Kniazeff,
An intracellular interaction network regulates conformational transitions in the dopamine transporter.
2008,
Pubmed
Krishnamurthy,
X-ray structures of LeuT in substrate-free outward-open and apo inward-open states.
2012,
Pubmed
Kunkel,
Rapid and efficient site-specific mutagenesis without phenotypic selection.
1987,
Pubmed
Loland,
Defining proximity relationships in the tertiary structure of the dopamine transporter. Identification of a conserved glutamic acid as a third coordinate in the endogenous Zn(2+)-binding site.
1999,
Pubmed
Mager,
Steady states, charge movements, and rates for a cloned GABA transporter expressed in Xenopus oocytes.
1993,
Pubmed
,
Xenbase
Mager,
Ion binding and permeation at the GABA transporter GAT1.
1996,
Pubmed
,
Xenbase
Mari,
Role of the conserved glutamine 291 in the rat gamma-aminobutyric acid transporter rGAT-1.
2006,
Pubmed
Nelson,
The family of Na+/Cl- neurotransmitter transporters.
1998,
Pubmed
Norregaard,
Delineation of an endogenous zinc-binding site in the human dopamine transporter.
1998,
Pubmed
Pantanowitz,
Only one of the charged amino acids located in the transmembrane alpha-helices of the gamma-aminobutyric acid transporter (subtype A) is essential for its activity.
1993,
Pubmed
Rosenberg,
The substrates of the gamma-aminobutyric acid transporter GAT-1 induce structural rearrangements around the interface of transmembrane domains 1 and 6.
2008,
Pubmed
Vandenberg,
Molecular basis for substrate discrimination by glycine transporters.
2007,
Pubmed
,
Xenbase
Yamashita,
Crystal structure of a bacterial homologue of Na+/Cl--dependent neurotransmitter transporters.
2005,
Pubmed
Zhang,
The cytoplasmic substrate permeation pathway of serotonin transporter.
2006,
Pubmed
Zhou,
Identification of a lithium interaction site in the gamma-aminobutyric acid (GABA) transporter GAT-1.
2006,
Pubmed