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Li Y, Guo Y, Bröer A, Dai L, Brӧer S, Yan R. Cryo-EM structure of the human Asc-1 transporter complex. Nat Commun 2024; 15:3036. [PMID: 38589439 PMCID: PMC11001984 DOI: 10.1038/s41467-024-47468-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 04/02/2024] [Indexed: 04/10/2024] Open
Abstract
The Alanine-Serine-Cysteine transporter 1 (Asc-1 or SLC7A10) forms a crucial heterodimeric transporter complex with 4F2hc (SLC3A2) through a covalent disulfide bridge. This complex enables the sodium-independent transport of small neutral amino acids, including L-Alanine (L-Ala), Glycine (Gly), and D-Serine (D-Ser), within the central nervous system (CNS). D-Ser and Gly are two key endogenous glutamate co-agonists that activate N-methyl-d-aspartate (NMDA) receptors by binding to the allosteric site. Mice deficient in Asc-1 display severe symptoms such as tremors, ataxia, and seizures, leading to early postnatal death. Despite its physiological importance, the functional mechanism of the Asc-1-4F2hc complex has remained elusive. Here, we present cryo-electron microscopy (cryo-EM) structures of the human Asc-1-4F2hc complex in its apo state, D-Ser bound state, and L-Ala bound state, resolved at 3.6 Å, 3.5 Å, and 3.4 Å, respectively. Through detailed structural analysis and transport assays, we uncover a comprehensive alternating access mechanism that underlies conformational changes in the complex. In summary, our findings reveal the architecture of the Asc-1 and 4F2hc complex and provide valuable insights into substrate recognition and the functional cycle of this essential transporter complex.
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Affiliation(s)
- Yaning Li
- Department of Biochemistry, Key University Laboratory of Metabolism and Health of Guangdong, School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong Province, China
- Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, Guangdong Province, China
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yingying Guo
- Department of Biochemistry, Key University Laboratory of Metabolism and Health of Guangdong, School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong Province, China
| | - Angelika Bröer
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Lu Dai
- Department of Biochemistry, Key University Laboratory of Metabolism and Health of Guangdong, School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong Province, China
| | - Stefan Brӧer
- Research School of Biology, Australian National University, Canberra, ACT, Australia.
| | - Renhong Yan
- Department of Biochemistry, Key University Laboratory of Metabolism and Health of Guangdong, School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong Province, China.
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Cheng X, Wang Y, Gong G, Shen P, Li Z, Bian J. Design strategies and recent development of bioactive modulators for glutamine transporters. Drug Discov Today 2024; 29:103880. [PMID: 38216118 DOI: 10.1016/j.drudis.2024.103880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 12/25/2023] [Accepted: 01/08/2024] [Indexed: 01/14/2024]
Abstract
Glutamine transporters are integral to the metabolism of glutamine in both healthy tissues and cancerous cells, playing a pivotal role in maintaining amino acid balance, synthesizing biomolecules, and regulating redox equilibrium. Their critical functions in cellular metabolism make them promising targets for oncological therapies. Recent years have witnessed substantial progress in the field of glutamine transporters, marked by breakthroughs in understanding of their protein structures and the discovery of novel inhibitors, prodrugs, and radiotracers. This review provides a comprehensive update on the latest advancements in modulators targeting the glutamine transporter, with special attention given to LAT1 and ASCT2. It also discusses innovative approaches in drug design aimed at these transporters.
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Affiliation(s)
- Xinying Cheng
- School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Yezhi Wang
- School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Guangyue Gong
- School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Pei Shen
- School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Zhiyu Li
- School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China.
| | - Jinlei Bian
- School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China.
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El Hindi K, Brachtendorf S, Hartel JC, Renné C, Birod K, Schilling K, Labocha S, Thomas D, Ferreirós N, Hahnefeld L, Dorochow E, Del Turco D, Deller T, Scholich K, Fuhrmann DC, Weigert A, Brüne B, Geisslinger G, Wittig I, Link KH, Grösch S. Hypoxia induced deregulation of sphingolipids in colon cancer is a prognostic marker for patient outcome. Biochim Biophys Acta Mol Basis Dis 2024; 1870:166906. [PMID: 37802156 DOI: 10.1016/j.bbadis.2023.166906] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 09/26/2023] [Accepted: 09/27/2023] [Indexed: 10/08/2023]
Abstract
Sphingolipids are important for the physicochemical properties of cellular membranes and deregulated in tumors. In human colon cancer tissue ceramide synthase (CerS) 4 and CerS5 are reduced which correlates with a reduced survival probability of late-stage colon cancer patients. Both enzymes are reduced after hypoxia in advanced colorectal cancer (CRC) cells (HCT-116, SW620) but not in non-metastatic CRC cells (SW480, Caco-2). Downregulation of CerS4 or CerS5 in advanced CRC cells enhanced tumor formation in nude mice and organoid growth in vitro. This was accompanied by an enhanced proliferation rate and metabolic changes leading to a shift towards the Warburg effect. In contrast, CerS4 or CerS5 depletion in Caco-2 cells reduced tumor growth in vivo. Lipidomic and proteomic analysis of membrane fractions revealed significant changes in tumor-promoting cellular pathways and cellular transporters. This study identifies CerS4 and CerS5 as prognostic markers for advanced colon cancer patients and provides a comprehensive overview about the associated cellular metabolic changes. We propose that the expression level of CerS4 and CerS5 in colon tumors could serve as a basis for decision-making for personalized treatment of advanced colon cancer patients. Trial registration: The study was accredited by the study board of the Deutsche Krebsgesellschaft (Registration No: St-D203, 2017/06/30, retrospectively registered).
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Affiliation(s)
- Khadija El Hindi
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Faculty of Medicine, Theodor Stern Kai 7, 60590 Frankfurt, Germany
| | - Sebastian Brachtendorf
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Faculty of Medicine, Theodor Stern Kai 7, 60590 Frankfurt, Germany
| | - Jennifer C Hartel
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Faculty of Medicine, Theodor Stern Kai 7, 60590 Frankfurt, Germany; Goethe-University Frankfurt, Department of Life Sciences, 60590 Frankfurt, Germany
| | - Christoph Renné
- Institute of Pathology and Cytology, Group Practice Wiesbaden, Germany
| | - Kerstin Birod
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Faculty of Medicine, Theodor Stern Kai 7, 60590 Frankfurt, Germany
| | - Karin Schilling
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Faculty of Medicine, Theodor Stern Kai 7, 60590 Frankfurt, Germany
| | - Sandra Labocha
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Faculty of Medicine, Theodor Stern Kai 7, 60590 Frankfurt, Germany
| | - Dominique Thomas
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Faculty of Medicine, Theodor Stern Kai 7, 60590 Frankfurt, Germany; Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany; Fraunhofer Cluster of Excellence for Immune-Mediated Diseases CIMD, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany
| | - Nerea Ferreirós
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Faculty of Medicine, Theodor Stern Kai 7, 60590 Frankfurt, Germany
| | - Lisa Hahnefeld
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Faculty of Medicine, Theodor Stern Kai 7, 60590 Frankfurt, Germany; Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany; Fraunhofer Cluster of Excellence for Immune-Mediated Diseases CIMD, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany
| | - Erika Dorochow
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Faculty of Medicine, Theodor Stern Kai 7, 60590 Frankfurt, Germany
| | - Domenico Del Turco
- Goethe-University Frankfurt, Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Faculty of Medicine, Theodor Stern Kai 7, 60596 Frankfurt am Main, Germany
| | - Thomas Deller
- Goethe-University Frankfurt, Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Faculty of Medicine, Theodor Stern Kai 7, 60596 Frankfurt am Main, Germany
| | - Klaus Scholich
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Faculty of Medicine, Theodor Stern Kai 7, 60590 Frankfurt, Germany; Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany
| | - Dominik C Fuhrmann
- Goethe-University Frankfurt, Institute of Biochemistry I, Faculty of Medicine, Theodor-Stern-Kai 7, 60596 Frankfurt, Germany
| | - Andreas Weigert
- Goethe-University Frankfurt, Institute of Biochemistry I, Faculty of Medicine, Theodor-Stern-Kai 7, 60596 Frankfurt, Germany
| | - Bernhard Brüne
- Goethe-University Frankfurt, Institute of Biochemistry I, Faculty of Medicine, Theodor-Stern-Kai 7, 60596 Frankfurt, Germany
| | - Gerd Geisslinger
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Faculty of Medicine, Theodor Stern Kai 7, 60590 Frankfurt, Germany; Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany; Fraunhofer Cluster of Excellence for Immune-Mediated Diseases CIMD, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany
| | - Ilka Wittig
- Goethe-University Frankfurt, Functional Proteomics, Institute of Cardiovascular Physiology, Faculty of Medicine, Frankfurt am Main, Germany
| | - Karl-Heinrich Link
- Asklepios Tumor Center (ATC) and Surgical Center, Asklepios Paulinen Klinik, Wiesbaden 65197, Germany
| | - Sabine Grösch
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Faculty of Medicine, Theodor Stern Kai 7, 60590 Frankfurt, Germany; Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany.
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Krishnan KS, Billups B. ASC Transporters Mediate D-Serine Transport into Astrocytes Adjacent to Synapses in the Mouse Brain. Biomolecules 2023; 13:biom13050819. [PMID: 37238689 DOI: 10.3390/biom13050819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/08/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
D-serine is an important signalling molecule, which activates N-methyl D-aspartate receptors (NMDARs) in conjunction with its fellow co-agonist, the neurotransmitter glutamate. Despite its involvement in plasticity and memory related to excitatory synapses, its cellular source and sink remain a question. We hypothesise that astrocytes, a type of glial cell that surrounds synapses, are likely candidates to control the extracellular concentration of D-Serine by removing it from the synaptic space. Using in situ patch clamp recordings and pharmacological manipulation of astrocytes in the CA1 region of the mouse hippocampal brain slices, we investigated the transport of D-serine across the plasma membrane. We observed the D-serine-induced transport-associated currents upon puff-application of 10 mM D-serine on astrocytes. Further, O-benzyl-L-serine and trans-4-hydroxy-proline, known substrate inhibitors of the alanine serine cysteine transporters (ASCT), reduced D-serine uptake. These results indicate that ASCT is a central mediator of astrocytic D-serine transport and plays a role in regulating its synaptic concentration by sequestration into astrocytes. Similar results were observed in astrocytes of the somatosensory cortex and Bergmann glia in the cerebellum, indicative of a general mechanism expressed across a range of brain areas. This removal of synaptic D-serine and its subsequent metabolic degradation are expected to reduce its extracellular availability, influencing NMDAR activation and NMDAR-dependent synaptic plasticity.
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Affiliation(s)
- Karthik Subramanian Krishnan
- Eccles Institute of Neuroscience, The John Curtin School of Medical Research, The Australian National University, 131 Garran Road, Canberra, ACT 2601, Australia
| | - Brian Billups
- Eccles Institute of Neuroscience, The John Curtin School of Medical Research, The Australian National University, 131 Garran Road, Canberra, ACT 2601, Australia
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