8gnk
CryoEM structure of cytosol-facing, substrate-bound ratGAT1
Structural highlights
FunctionSC6A1_RAT Mediates transport of gamma-aminobutyric acid (GABA) together with sodium and chloride and is responsible for the reuptake of GABA from the synapse (PubMed:18054861, PubMed:1975955). The translocation of GABA, however, may also occur in the reverse direction leading to the release of GABA (PubMed:18054861, PubMed:21775701). The direction and magnitude of GABA transport is a consequence of the prevailing thermodynamic conditions, determined by membrane potential and the intracellular and extracellular concentrations of Na(+), Cl(-) and GABA (PubMed:18054861, PubMed:21775701). Also mediates sodium- and chloride-dependent transport of hypotaurine (By similarity).[UniProtKB:P31648][1] [2] [3] Publication Abstract from PubMedThe inhibitory neurotransmitter gamma-aminobutyric acid (GABA) is cleared from the synaptic cleft by the sodium- and chloride-coupled GABA transporter GAT1. Inhibition of GAT1 prolongs the GABAergic signaling at the synapse and is a strategy to treat certain forms of epilepsy. In this study, we present the cryo-electron microscopy structure of Rattus norvegicus GABA transporter 1 (rGAT1) at a resolution of 3.1 A. The structure elucidation was facilitated by epitope transfer of a fragment-antigen binding (Fab) interaction site from the Drosophila dopamine transporter (dDAT) to rGAT1. The structure reveals rGAT1 in a cytosol-facing conformation, with a linear density in the primary binding site that accommodates a molecule of GABA, a displaced ion density proximal to Na site 1 and a bound chloride ion. A unique insertion in TM10 aids the formation of a compact, closed extracellular gate. Besides yielding mechanistic insights into ion and substrate recognition, our study will enable the rational design of specific antiepileptics. Cryo-EM structure of GABA transporter 1 reveals substrate recognition and transport mechanism.,Nayak SR, Joseph D, Hofner G, Dakua A, Athreya A, Wanner KT, Kanner BI, Penmatsa A Nat Struct Mol Biol. 2023 Jul;30(7):1023-1032. doi: 10.1038/s41594-023-01011-w. , Epub 2023 Jul 3. PMID:37400654[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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