Structure and allosteric inhibition of excitatory amino acid transporter 1

• Published in: Nature (London) 2017-04, Vol.544 (7651), p.446-451
• Main Authors: Canul-Tec, Juan C., Assal, Reda, Cirri, Erica, Legrand, Pierre, Brier, Sébastien, Chamot-Rooke, Julia, Reyes, Nicolas
• Format: Article
• Language: English
• Subjects: 101/58; 631/378/340; 631/45/612/1237; 631/57/2283; 82/16; Allosteric Regulation - drug effects; Allosteric Site; Allosteric Site - drug effects; Amino acids; Binding sites; Crystallization; Crystallography, X-Ray; Deuterium; Deuterium Exchange Measurement; Excitatory Amino Acid Transporter 1; Excitatory Amino Acid Transporter 1 - antagonists & inhibitors; Excitatory Amino Acid Transporter 1 - chemistry; Excitatory Amino Acid Transporter 1 - metabolism; Humanities and Social Sciences; Humans; Life Sciences; Lipids; Mass Spectrometry; Models, Molecular; multidisciplinary; Mutation; Pharmacology; Potassium; Protein Domains; Protein Domains - drug effects; Proteins; Science; Sodium
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature22064

Human members of the solute carrier 1 (SLC1) family of transporters take up excitatory neurotransmitters in the brain and amino acids in peripheral organs. Dysregulation of the function of SLC1 transporters is associated with neurodegenerative disorders and cancer. Here we present crystal structures of a thermostabilized human SLC1 transporter, the excitatory amino acid transporter 1 (EAAT1), with and without allosteric and competitive inhibitors bound. The structures reveal architectural features of the human transporters, such as intra- and extracellular domains that have potential roles in transport function, regulation by lipids and post-translational modifications. The coordination of the allosteric inhibitor in the structures and the change in the transporter dynamics measured by hydrogen–deuterium exchange mass spectrometry reveal a mechanism of inhibition, in which the transporter is locked in the outward-facing states of the transport cycle. Our results provide insights into the molecular mechanisms underlying the function and pharmacology of human SLC1 transporters. High-resolution structures of the thermostabilized human excitatory amino acid transporter EAAT1, alone or in association with its substrate or small molecule inhibitors, reveal architectural features of human SLC1 transporters and an allosteric mechanism of inhibition. Structure of an amino acid transporter Amino acid transporters of the solute carrier 1 (SLC1) family have been associated with several neurological and metabolic disorders in humans, but information about their structure has been limited to a simpler homologue from an archeal microorganism. Nicolas Reyes and colleagues present several high-resolution structures of the human excitatory amino acid transporter 1 (EAAT1), a key component of glutamatergic synapses, alone or in association with its substrate or small inhibitor molecules. The structures reveal mechanistic determinants that are specific to human SLC1 carriers, such as regulation by lipids or post-translational modifications, and present an allosteric pocket that could aid further drug design. On the basis of these structures, researchers will be able to propose how specific mutations affect EAAT1 transport mechanics at a molecular level and therefore suggest more effective treatment approaches.