1
|
Hutchinson K, Schlessinger A. Comprehensive Characterization of LAT1 Cholesterol-Binding Sites. J Chem Theory Comput 2024; 20:3349-3358. [PMID: 38597304 DOI: 10.1021/acs.jctc.3c01391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
The human L-type amino acid transporter 1 (LAT1; SLC7A5), is an amino acid exchanger protein, primarily found in the blood-brain barrier, placenta, and testis, where it plays a key role in amino acid homeostasis. Cholesterol is an essential lipid that has been highlighted to play a role in regulating the activity of membrane transporters, such as LAT1, yet little is known about the molecular mechanisms driving this phenomenon. Here we perform a comprehensive computational analysis to investigate cholesterol's role in LAT1 structure and function, focusing on four cholesterol-binding sites (CHOL1-4) identified in a recent LAT1-apo inward-open conformation cryo-EM structure. Through a series of independent molecular dynamics (MD) simulations, molecular docking, MM/GBSA free energy calculations, and other analysis tools, we explored the interactions between LAT1 and cholesterol. Our findings suggest that CHOL3 forms the most stable and favorable interactions with LAT1. Principal component analysis (PCA) and center of mass (COM) distance assessments show that CHOL3 binding stabilizes the inward-open state of LAT1 by preserving the spatial arrangement of the hash and bundle domains. Additionally, we propose an alternative cholesterol-binding site for originally assigned CHOL1. Overall, this study improves the understanding of cholesterol's modulatory effect on LAT1 and proposes candidate sites for the discovery of future allosteric ligands with rational design.
Collapse
Affiliation(s)
- Keino Hutchinson
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Avner Schlessinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
- Department of Artificial Intelligence and Human Health, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| |
Collapse
|
2
|
Galluccio M, Mazza T, Scalise M, Tripicchio M, Scarpelli M, Tolomeo M, Pochini L, Indiveri C. Over-Production of the Human SLC7A10 in E. coli and Functional Assay in Proteoliposomes. Int J Mol Sci 2023; 25:536. [PMID: 38203703 PMCID: PMC10779382 DOI: 10.3390/ijms25010536] [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: 11/30/2023] [Revised: 12/28/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024] Open
Abstract
The human SLC7A10 transporter, also known as ASC-1, catalyzes the transport of some neutral amino acids. It is expressed in astrocytes, neurons, and adipose tissues, playing roles in learning, memory processes, and lipid metabolism, thus being involved in neurological and metabolic pathologies. Structure/function studies on this transporter are still in their infancy. In this study, we present a methodology for producing the recombinant human transporter in E. coli. Its transport function was assayed in proteoliposomes following the uptake of radiolabeled L-serine. After the testing of several growth conditions, the hASC-1 transporter was successfully expressed in BL21(DE3) codon plus RIL in the presence of 0.5% glucose and induced with 0.05 mM IPTG. After solubilization with C12E8 and cholesteryl hemisuccinate and purification by Ni-chelating chromatography, hASC-1 was reconstituted in proteoliposomes. In this experimental system it was able to catalyze an Na+-independent homologous antiport of L-serine. A Km for L-serine transport of 0.24 mM was measured. The experimental model developed in this work represents a reproducible system for the transport assay of hASC-1 in the absence of interferences. This tool will be useful to unveil unknown transport properties of hASC-1 and for testing ligands with possible application in human pharmacology.
Collapse
Affiliation(s)
- Michele Galluccio
- Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, Department DiBEST (Biologia, Ecologia e Scienze della Terra), University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy; (T.M.); (M.S.); (M.T.); (M.S.); (M.T.); (L.P.)
| | - Tiziano Mazza
- Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, Department DiBEST (Biologia, Ecologia e Scienze della Terra), University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy; (T.M.); (M.S.); (M.T.); (M.S.); (M.T.); (L.P.)
| | - Mariafrancesca Scalise
- Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, Department DiBEST (Biologia, Ecologia e Scienze della Terra), University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy; (T.M.); (M.S.); (M.T.); (M.S.); (M.T.); (L.P.)
| | - Martina Tripicchio
- Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, Department DiBEST (Biologia, Ecologia e Scienze della Terra), University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy; (T.M.); (M.S.); (M.T.); (M.S.); (M.T.); (L.P.)
| | - Martina Scarpelli
- Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, Department DiBEST (Biologia, Ecologia e Scienze della Terra), University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy; (T.M.); (M.S.); (M.T.); (M.S.); (M.T.); (L.P.)
| | - Maria Tolomeo
- Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, Department DiBEST (Biologia, Ecologia e Scienze della Terra), University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy; (T.M.); (M.S.); (M.T.); (M.S.); (M.T.); (L.P.)
| | - Lorena Pochini
- Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, Department DiBEST (Biologia, Ecologia e Scienze della Terra), University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy; (T.M.); (M.S.); (M.T.); (M.S.); (M.T.); (L.P.)
- National Research Council (CNR), Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy
| | - Cesare Indiveri
- Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, Department DiBEST (Biologia, Ecologia e Scienze della Terra), University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy; (T.M.); (M.S.); (M.T.); (M.S.); (M.T.); (L.P.)
- National Research Council (CNR), Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy
| |
Collapse
|
3
|
Scanga R, Scalise M, Marino N, Parisi F, Barca D, Galluccio M, Brunocilla C, Console L, Indiveri C. LAT1 (SLC7A5) catalyzes copper(histidinate) transport switching from antiport to uniport mechanism. iScience 2023; 26:107738. [PMID: 37692288 PMCID: PMC10492218 DOI: 10.1016/j.isci.2023.107738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/31/2023] [Accepted: 08/23/2023] [Indexed: 09/12/2023] Open
Abstract
LAT1 (SLC7A5) is one of the most studied membrane transporters due to its relevance to physiology in supplying essential amino acids to brain and fetus, and to pathology being linked to nervous or embryo alterations; moreover, LAT1 over-expression is always associated with cancer development. Thus, LAT1 is exploited as a pro-drug vehicle and as a target for anti-cancer therapy. We here report the identification of a new substrate with pathophysiological implications, i.e., Cu-histidinate, and an unconventional uniport mechanism exploited for the Cu-histidinate transport. Crystals of the monomeric species Cu(His)2 were obtained in our experimental conditions and the actual transport of the complex was evaluated by a combined strategy of bioinformatics, site-directed mutagenesis, radiolabeled transport, and mass spectrometry analysis. The LAT1-mediated transport of Cu(His)2 may have profound implications for both the treatment of copper dysmetabolism diseases, such as the rare Menkes disease, and of cancer as an alternative to platinum-based therapies.
Collapse
Affiliation(s)
- Raffaella Scanga
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, 87036 Arcavacata di Rende, Italy
| | - Mariafrancesca Scalise
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, 87036 Arcavacata di Rende, Italy
| | - Nadia Marino
- MAT-INLAB (Laboratorio di Materiali Molecolari Inorganici), Department of Chemistry and Chemical Technologies (CTC), University of Calabria—UNICAL, Via P. Bucci, 87036 Arcavacata di Rende, Italy
| | - Francesco Parisi
- MAT-INLAB (Laboratorio di Materiali Molecolari Inorganici), Department of Chemistry and Chemical Technologies (CTC), University of Calabria—UNICAL, Via P. Bucci, 87036 Arcavacata di Rende, Italy
| | - Donatella Barca
- Department DiBEST (Biologia, Ecologia e Scienze della Terra), 87036 Arcavacata di Rende, Italy
| | - Michele Galluccio
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, 87036 Arcavacata di Rende, Italy
| | - Chiara Brunocilla
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, 87036 Arcavacata di Rende, Italy
| | - Lara Console
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, 87036 Arcavacata di Rende, Italy
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, 87036 Arcavacata di Rende, Italy
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), 70126 Bari, Italy
| |
Collapse
|
4
|
Insights into the Transport Cycle of LAT1 and Interaction with the Inhibitor JPH203. Int J Mol Sci 2023; 24:ijms24044042. [PMID: 36835453 PMCID: PMC9965313 DOI: 10.3390/ijms24044042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/08/2023] [Accepted: 02/15/2023] [Indexed: 02/19/2023] Open
Abstract
The large Amino Acid Transporter 1 (LAT1) is an interesting target in drug discovery since this transporter is overexpressed in several human cancers. Furthermore, due to its location in the blood-brain barrier (BBB), LAT1 is interesting for delivering pro-drugs to the brain. In this work, we focused on defining the transport cycle of LAT1 using an in silico approach. So far, studies of the interaction of LAT1 with substrates and inhibitors have not considered that the transporter must undergo at least four different conformations to complete the transport cycle. We built outward-open and inward-occluded conformations of LAT1 using an optimized homology modelling procedure. We used these 3D models and the cryo-EM structures in outward-occluded and inward-open conformations to define the substrate/protein interaction during the transport cycle. We found that the binding scores for the substrate depend on the conformation, with the occluded states as the crucial steps affecting the substrate affinity. Finally, we analyzed the interaction of JPH203, a high-affinity inhibitor of LAT1. The results indicate that conformational states must be considered for in silico analyses and early-stage drug discovery. The two built models, together with the available cryo-EM 3D structures, provide important information on the LAT1 transport cycle, which could be used to speed up the identification of potential inhibitors through in silico screening.
Collapse
|
5
|
Austin S, Mekis R, Mohammed SEM, Scalise M, Wang W, Galluccio M, Pfeiffer C, Borovec T, Parapatics K, Vitko D, Dinhopl N, Demaurex N, Bennett KL, Indiveri C, Nowikovsky K. TMBIM5 is the Ca 2+ /H + antiporter of mammalian mitochondria. EMBO Rep 2022; 23:e54978. [PMID: 36321428 PMCID: PMC9724676 DOI: 10.15252/embr.202254978] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 09/07/2022] [Accepted: 10/07/2022] [Indexed: 11/25/2022] Open
Abstract
Mitochondrial Ca2+ ions are crucial regulators of bioenergetics and cell death pathways. Mitochondrial Ca2+ content and cytosolic Ca2+ homeostasis strictly depend on Ca2+ transporters. In recent decades, the major players responsible for mitochondrial Ca2+ uptake and release have been identified, except the mitochondrial Ca2+ /H+ exchanger (CHE). Originally identified as the mitochondrial K+ /H+ exchanger, LETM1 was also considered as a candidate for the mitochondrial CHE. Defining the mitochondrial interactome of LETM1, we identify TMBIM5/MICS1, the only mitochondrial member of the TMBIM family, and validate the physical interaction of TMBIM5 and LETM1. Cell-based and cell-free biochemical assays demonstrate the absence or greatly reduced Na+ -independent mitochondrial Ca2+ release in TMBIM5 knockout or pH-sensing site mutants, respectively, and pH-dependent Ca2+ transport by recombinant TMBIM5. Taken together, we demonstrate that TMBIM5, but not LETM1, is the long-sought mitochondrial CHE, involved in setting and regulating the mitochondrial proton gradient. This finding provides the final piece of the puzzle of mitochondrial Ca2+ transporters and opens the door to exploring its importance in health and disease, and to developing drugs modulating Ca2+ exchange.
Collapse
Affiliation(s)
- Shane Austin
- Department of Internal Medicine I and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
- Present address:
Department of Biological & Chemical SciencesThe University of the West Indies, Cave Hill CampusCave HillBarbados
| | - Ronald Mekis
- Department of Internal Medicine I and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and BiophysicsUniversity of Veterinary Medicine ViennaViennaAustria
| | - Sami E M Mohammed
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and BiophysicsUniversity of Veterinary Medicine ViennaViennaAustria
| | - Mariafrancesca Scalise
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular BiotechnologyUniversity of CalabriaArcavacata di RendeItaly
| | - Wen‐An Wang
- Department of Cell Physiology & MetabolismUniversity of GenevaGenevaSwitzerland
| | - Michele Galluccio
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular BiotechnologyUniversity of CalabriaArcavacata di RendeItaly
| | - Christina Pfeiffer
- Department of Internal Medicine I and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
| | - Tamara Borovec
- Department of Internal Medicine I and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and BiophysicsUniversity of Veterinary Medicine ViennaViennaAustria
| | - Katja Parapatics
- CeMM Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Dijana Vitko
- CeMM Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Nora Dinhopl
- Department of Pathobiology, Institute of PathologyUniversity of Veterinary MedicineViennaAustria
| | - Nicolas Demaurex
- Department of Cell Physiology & MetabolismUniversity of GenevaGenevaSwitzerland
| | - Keiryn L Bennett
- CeMM Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular BiotechnologyUniversity of CalabriaArcavacata di RendeItaly
- CNR Institute of BiomembranesBioenergetics and Molecular Biotechnologies (IBIOM)BariItaly
| | - Karin Nowikovsky
- Department of Internal Medicine I and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and BiophysicsUniversity of Veterinary Medicine ViennaViennaAustria
| |
Collapse
|
6
|
Hutchinson K, Silva DB, Bohlke J, Clausen C, Thomas AA, Bonomi M, Schlessinger A. Describing inhibitor specificity for the amino acid transporter LAT1 from metainference simulations. Biophys J 2022; 121:4476-4491. [PMID: 36369754 PMCID: PMC9748366 DOI: 10.1016/j.bpj.2022.11.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 09/09/2022] [Accepted: 10/31/2022] [Indexed: 11/13/2022] Open
Abstract
The human L-type amino acid transporter 1 (LAT1; SLC7A5) is a membrane transporter of amino acids, thyroid hormones, and drugs such as the Parkinson's disease drug levodopa (L-Dopa). LAT1 is found in the blood-brain barrier, testis, bone marrow, and placenta, and its dysregulation has been associated with various neurological diseases, such as autism and epilepsy, as well as cancer. In this study, we combine metainference molecular dynamics simulations, molecular docking, and experimental testing, to characterize LAT1-inhibitor interactions. We first conducted a series of molecular docking experiments to identify the most relevant interactions between LAT1's substrate-binding site and ligands, including both inhibitors and substrates. We then performed metainference molecular dynamics simulations using cryoelectron microscopy structures in different conformations of LAT1 with the electron density map as a spatial restraint, to explore the inherent heterogeneity in the structures. We analyzed the LAT1 substrate-binding site to map important LAT1-ligand interactions as well as newly described druggable pockets. Finally, this analysis guided the discovery of previously unknown LAT1 ligands using virtual screening and cellular uptake experiments. Our results improve our understanding of LAT1-inhibitor recognition, providing a framework for rational design of future lead compounds targeting this key drug target.
Collapse
Affiliation(s)
- Keino Hutchinson
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Dina Buitrago Silva
- Department of Bioengineering and Therapeutic Sciences University of California, San Francisco, San Francisco, California
| | - Joshua Bohlke
- Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska
| | - Chase Clausen
- Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska
| | - Allen A Thomas
- Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska
| | - Massimiliano Bonomi
- Department of Structural Biology and Chemistry, Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Paris, France.
| | - Avner Schlessinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York.
| |
Collapse
|
7
|
Structural and functional investigation of ABC transporter STE6-2p from Pichia pastoris reveals unexpected interaction with sterol molecules. Proc Natl Acad Sci U S A 2022; 119:e2202822119. [PMID: 36256814 PMCID: PMC9618074 DOI: 10.1073/pnas.2202822119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Adenosine triphosphate (ATP)-binding cassette (ABC) transporters are multidomain transmembrane proteins, which facilitate the transport of various substances across cell membranes using energy derived from ATP hydrolysis. They are important drug targets since they mediate decreased drug susceptibility during pharmacological treatments. For the methylotrophic yeast Pichia pastoris, a model organism that is a widely used host for protein expression, the role and function of its ABC transporters is unexplored. In this work, we investigated the Pichia ABC-B transporter STE6-2p. Functional investigations revealed that STE6-2p is capable of transporting rhodamines in vivo and is active in the presence of verapamil and triazoles in vitro. A phylogenetic analysis displays homology among multidrug resistance (MDR) transporters from pathogenic fungi to human ABC-B transporters. Further, we present high-resolution single-particle electron cryomicroscopy structures of an ABC transporter from P. pastoris in the apo conformation (3.1 Å) and in complex with verapamil and adenylyl imidodiphosphate (AMP-PNP) (3.2 Å). An unknown density between transmembrane helices 4, 5, and 6 in both structures suggests the presence of a sterol-binding site of unknown function.
Collapse
|
8
|
Huang H, Dai Y, Duan Y, Yuan Z, Li Y, Zhang M, Zhu W, Yu H, Zhong W, Feng S. Effective prediction of potential ferroptosis critical genes in clinical colorectal cancer. Front Oncol 2022; 12:1033044. [PMID: 36324584 PMCID: PMC9619366 DOI: 10.3389/fonc.2022.1033044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 09/27/2022] [Indexed: 08/30/2023] Open
Abstract
BACKGROUND Colon cancer is common worldwide, with high morbidity and poor prognosis. Ferroptosis is a novel form of cell death driven by the accumulation of iron-dependent lipid peroxides, which differs from other programmed cell death mechanisms. Programmed cell death is a cancer hallmark, and ferroptosis is known to participate in various cancers, including colon cancer. Novel ferroptosis markers and targeted colon cancer therapies are urgently needed. To this end, we performed a preliminary exploration of ferroptosis-related genes in colon cancer to enable new treatment strategies. METHODS Ferroptosis-related genes in colon cancer were obtained by data mining and screening for differentially expressed genes (DEGs) using bioinformatics analysis tools. We normalized the data across four independent datasets and a ferroptosis-specific database. Identified genes were validated by immunohistochemical analysis of pathological and healthy clinical samples. RESULTS We identified DEGs in colon cancer that are involved in ferroptosis. Among these, five core genes were found: ELAVL1, GPX2, EPAS1, SLC7A5, and HMGB1. Bioinformatics analyses revealed that the expression of all five genes, except for EPAS1, was higher in tumor tissues than in healthy tissues. CONCLUSIONS The preliminary exploration of the five core genes revealed that they are differentially expressed in colon cancer, playing an essential role in ferroptosis. This study provides a foundation for subsequent research on ferroptosis in colon cancer.
Collapse
Affiliation(s)
- Hongliang Huang
- Department of Pharmacy, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangzhou, China
- School of Pharmaceutical Sciences, Guangzhou Medical University, Guangzhou, China
| | - Yuexiang Dai
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou, China
| | - Yingying Duan
- Department of Pharmacy, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangzhou, China
- School of Pharmaceutical Sciences, Guangzhou Medical University, Guangzhou, China
| | - Zhongwen Yuan
- Department of Pharmacy, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangzhou, China
- School of Pharmaceutical Sciences, Guangzhou Medical University, Guangzhou, China
| | - Yanxuan Li
- The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Maomao Zhang
- The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Wenting Zhu
- Department of Pharmacy, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangzhou, China
| | - Hang Yu
- Department of Pharmacy, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangzhou, China
| | - Wenfei Zhong
- Department of Pharmacy, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangzhou, China
| | - Senling Feng
- Department of Pharmacy, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangzhou, China
- School of Pharmaceutical Sciences, Guangzhou Medical University, Guangzhou, China
| |
Collapse
|
9
|
Galluccio M, Scalise M, Pappacoda G, Scarpelli M, Bonanomi M, Gaglio D, Indiveri C. Production of recombinant human xCT (SLC7A11) and reconstitution in proteoliposomes for functional studies. Front Physiol 2022; 13:993626. [PMID: 36148304 PMCID: PMC9485625 DOI: 10.3389/fphys.2022.993626] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/16/2022] [Indexed: 11/13/2022] Open
Abstract
The plasma membrane transporter xCT belongs to the SLC7 family and has the physiological role of mediating the exchange of glutamate and cystine across the cell plasma membrane, being crucial for redox control. The xCT protein forms a heterodimer with the ancillary protein CD98. Over the years, xCT became a hot pharmacological target due to the documented over-expression in virtually all human cancers, which rely on cystine availability for their progression. Notwithstanding, several unknown aspects of xCT biology still exist that require a suitable single protein experimental model, to be addressed. To this aim, the recombinant host Escherichia coli has been exploited to over-express the human isoform of xCT. In this widely used and low-cost system, the optimization for growth and protein production has been achieved by acting on the metabolic needs of the bacterial strains. Then, the His-tagged protein has been purified by Ni2+-chelating chromatography and reconstituted in proteoliposomes for transport activity assays. The expressed protein was in a folded/active state allowing functional and kinetic characterization. Interestingly, the features of the recombinant protein meet those of the native one extracted from intact cells, further confirming the suitability of E. coli as a host for the expression of human proteins. This study opens perspectives for elucidating other molecular aspects of xCT, as well as for studying the interaction with endogenous and exogenous compounds, relevant to human health.
Collapse
Affiliation(s)
- Michele Galluccio
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia Ecologia Scienze della Terra), University of Calabria, Arcavacata di Rende, Italy
| | - Mariafrancesca Scalise
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia Ecologia Scienze della Terra), University of Calabria, Arcavacata di Rende, Italy
| | - Gilda Pappacoda
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia Ecologia Scienze della Terra), University of Calabria, Arcavacata di Rende, Italy
| | - Martina Scarpelli
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia Ecologia Scienze della Terra), University of Calabria, Arcavacata di Rende, Italy
| | - Marcella Bonanomi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
- ISBE.IT/Centre of Systems Biology, Milan, Italy
| | - Daniela Gaglio
- ISBE.IT/Centre of Systems Biology, Milan, Italy
- Institute of Molecular Bioimaging and Physiology (IBFM), National Research Council (CNR), Milan, Italy
| | - Cesare Indiveri
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia Ecologia Scienze della Terra), University of Calabria, Arcavacata di Rende, Italy
- CNR Institute of Biomembranes, Bioenergetics, and Molecular Biotechnologies (IBIOM), Bari, Italy
- *Correspondence: Cesare Indiveri,
| |
Collapse
|
10
|
Galluccio M, Mazza T, Scalise M, Sarubbi MC, Indiveri C. Bacterial over-expression of functionally active human CT2 (SLC22A16) carnitine transporter. Mol Biol Rep 2022; 49:8185-8193. [PMID: 35608746 DOI: 10.1007/s11033-022-07491-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 04/20/2022] [Indexed: 01/11/2023]
Abstract
BACKGROUND Escherichia coli is a widely used tool for the over-expression of human proteins for studying structure and function. The toxicity of human proteins for E. coli often hampers the expression. This study aims to find conditions for the expression of a membrane transporter known as the carnitine transporter CT2. The knowledge on this transporter is scarce, thus obtaining the recombinant protein is very important for further studies. METHODS AND RESULTS The cDNAs coding for human CT2 (hCT2) was cloned in the pH6EX3 vector and different transformed E. coli strains were cultured in absence or in presence of glucose. hCT2 expression was obtained. The protein was purified and reconstituted into proteoliposomes in a functionally active state. CONCLUSIONS Using the appropriate IPTG concentration, together with the addition of glucose, hCT2 has been expressed in E. coli. The protein is active and shows capacity to transport carnitine in proteoliposomes. The results have a great interest in basic biochemistry of membrane transporters and applications to human health since hCT2 is involved in human pathology.
Collapse
Affiliation(s)
- Michele Galluccio
- Department DiBEST Biologia, Ecologia, Scienze Della Terra Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci cubo 4C, 87036, Arcavacata di Rende, Italy
| | - Tiziano Mazza
- Department DiBEST Biologia, Ecologia, Scienze Della Terra Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci cubo 4C, 87036, Arcavacata di Rende, Italy
| | - Mariafrancesca Scalise
- Department DiBEST Biologia, Ecologia, Scienze Della Terra Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci cubo 4C, 87036, Arcavacata di Rende, Italy
| | - Maria Chiara Sarubbi
- Department DiBEST Biologia, Ecologia, Scienze Della Terra Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci cubo 4C, 87036, Arcavacata di Rende, Italy
| | - Cesare Indiveri
- Department DiBEST Biologia, Ecologia, Scienze Della Terra Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci cubo 4C, 87036, Arcavacata di Rende, Italy. .,CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnology IBIOM, via Amendola 122/O, 70126, Bari, Italy.
| |
Collapse
|
11
|
Cappoli N, Jenkinson MD, Russo CD, Dickens D. LAT1, a novel pharmacological target for the treatment of glioblastoma. Biochem Pharmacol 2022; 201:115103. [PMID: 35618000 DOI: 10.1016/j.bcp.2022.115103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 05/18/2022] [Accepted: 05/18/2022] [Indexed: 11/02/2022]
Abstract
The L-Type Amino Acid transporter, LAT1 (SLC7A5), has a crucial role in mediating amino acid uptake into the cells, thus modulating cell growth and proliferation as well as other intracellular functions. Different studies have reported a central role of LAT1 in glioblastoma development and progression, suggesting that the modulation of its activity could be a novel therapeutic strategy. LAT1 also has an important role in the peripheral immune system, by regulating the activation status of several immune cells through modulation of the mechanistic target of rapamycin kinase. In glioblastoma (GBM), the blood-brain barrier is disrupted, which allows the recruitment of peripheral immune cells to the tumour site. These cells, together with resident microglia, contribute to cancer growth and progression. Currently, little is known about the function of LAT1 in the reprogramming of the immune component of the tumour microenvironment in the context of GBM. In this article, we review the available data on the role of LAT1 in the regulation of GBM biology, including its potential role in the tumour microenvironment, particularly in infiltrating-peripheral immune cells and resident microglial cells. In addition, we review the available data on the main pharmacological inhibitors of LAT1, aiming to evaluate their possible role as novel therapeutics for GBM.
Collapse
Affiliation(s)
- Natalia Cappoli
- Department of Healthcare Surveillance and Bioethics, Section of Pharmacology, Università Cattolica del Sacro Cuore-Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Michael D Jenkinson
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology (ISMIB), University of Liverpool, Liverpool, United Kingdom; Department of Neurosurgery, The Walton Centre NHS Foundation Trust, Liverpool, United Kingdom
| | - Cinzia Dello Russo
- Department of Healthcare Surveillance and Bioethics, Section of Pharmacology, Università Cattolica del Sacro Cuore-Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology (ISMIB), University of Liverpool, Liverpool, United Kingdom.
| | - David Dickens
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology (ISMIB), University of Liverpool, Liverpool, United Kingdom
| |
Collapse
|
12
|
Galluccio M, Console L, Pochini L, Scalise M, Giangregorio N, Indiveri C. Strategies for Successful Over-Expression of Human Membrane Transport Systems Using Bacterial Hosts: Future Perspectives. Int J Mol Sci 2022; 23:ijms23073823. [PMID: 35409183 PMCID: PMC8998559 DOI: 10.3390/ijms23073823] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/28/2022] [Accepted: 03/28/2022] [Indexed: 02/06/2023] Open
Abstract
Ten percent of human genes encode for membrane transport systems, which are key components in maintaining cell homeostasis. They are involved in the transport of nutrients, catabolites, vitamins, and ions, allowing the absorption and distribution of these compounds to the various body regions. In addition, roughly 60% of FDA-approved drugs interact with membrane proteins, among which are transporters, often responsible for pharmacokinetics and side effects. Defects of membrane transport systems can cause diseases; however, knowledge of the structure/function relationships of transporters is still limited. Among the expression of hosts that produce human membrane transport systems, E. coli is one of the most favorable for its low cultivation costs, fast growth, handiness, and extensive knowledge of its genetics and molecular mechanisms. However, the expression in E. coli of human membrane proteins is often toxic due to the hydrophobicity of these proteins and the diversity in structure with respect to their bacterial counterparts. Moreover, differences in codon usage between humans and bacteria hamper translation. This review summarizes the many strategies exploited to achieve the expression of human transport systems in bacteria, providing a guide to help people who want to deal with this topic.
Collapse
Affiliation(s)
- Michele Galluccio
- Unit of Biochemistry and Molecular Biotechnology, Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, Via P. Bucci 4c, Arcavacata di Rende, 87036 Cosenza, Italy; (M.G.); (L.C.); (L.P.); (M.S.)
| | - Lara Console
- Unit of Biochemistry and Molecular Biotechnology, Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, Via P. Bucci 4c, Arcavacata di Rende, 87036 Cosenza, Italy; (M.G.); (L.C.); (L.P.); (M.S.)
| | - Lorena Pochini
- Unit of Biochemistry and Molecular Biotechnology, Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, Via P. Bucci 4c, Arcavacata di Rende, 87036 Cosenza, Italy; (M.G.); (L.C.); (L.P.); (M.S.)
| | - Mariafrancesca Scalise
- Unit of Biochemistry and Molecular Biotechnology, Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, Via P. Bucci 4c, Arcavacata di Rende, 87036 Cosenza, Italy; (M.G.); (L.C.); (L.P.); (M.S.)
| | - Nicola Giangregorio
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnology (IBIOM), National Research Council (CNR), Via Amendola 165/A, 70126 Bari, Italy;
| | - Cesare Indiveri
- Unit of Biochemistry and Molecular Biotechnology, Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, Via P. Bucci 4c, Arcavacata di Rende, 87036 Cosenza, Italy; (M.G.); (L.C.); (L.P.); (M.S.)
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnology (IBIOM), National Research Council (CNR), Via Amendola 165/A, 70126 Bari, Italy;
- Correspondence:
| |
Collapse
|
13
|
Scanga R, Scalise M, Rovella F, Regina TMR, Galluccio M, Indiveri C. The Nutraceutical Alliin From Garlic Is a Novel Substrate of the Essential Amino Acid Transporter LAT1 (SLC7A5). Front Pharmacol 2022; 13:877576. [PMID: 35401172 PMCID: PMC8987110 DOI: 10.3389/fphar.2022.877576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 03/04/2022] [Indexed: 12/19/2022] Open
Abstract
The plasma membrane transporter LAT1 (SLC7A5) is a crucial player for cell homeostasis because it is responsible for providing cells with essential amino acids and hormones. LAT1 forms a functional heterodimer with the cell surface antigen heavy chain CD98 (also known as 4F2hc and SLC3A2), a type II membrane glycoprotein, which is essential for LAT1 stability and localization to the plasma membrane. The relevance of LAT1 for human metabolism is also related to its altered expression in human diseases, such as cancer and diabetes. These features boosted research toward molecules that are able to interact with LAT1; in this respect, the recent resolution of the LAT1-CD98 3D structure by Cryo-EM has opened important perspectives in the study of the interaction with different molecules in order to identify new drugs to be used in therapy or new substrates of natural origin to be employed as adjuvants and food supplements. In this work, the interaction of LAT1 with alliin, a garlic derivative, has been investigated by using a combined approach of bioinformatics and in vitro transport assays. Alliin is a nutraceutical that has several beneficial effects on human health, such as antidiabetic, anticarcinogenic, antioxidant, and anti-inflammatory properties. The computational analysis suggested that alliin interacts with the substrate binding site of LAT1, to which alliin was docked. These data were then confirmed by the competitive type inhibition measured in proteoliposomes. Interestingly, in the same experimental model, alliin was also revealed to be a substrate of LAT1.
Collapse
Affiliation(s)
- Raffaella Scanga
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze Della Terra), University of Calabria, Arcavacata di Rende, Italy
| | - Mariafrancesca Scalise
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze Della Terra), University of Calabria, Arcavacata di Rende, Italy
| | - Filomena Rovella
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze Della Terra), University of Calabria, Arcavacata di Rende, Italy
| | - Teresa Maria Rosaria Regina
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze Della Terra), University of Calabria, Arcavacata di Rende, Italy
| | - Michele Galluccio
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze Della Terra), University of Calabria, Arcavacata di Rende, Italy
| | - Cesare Indiveri
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze Della Terra), University of Calabria, Arcavacata di Rende, Italy
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Bari, Italy
- *Correspondence: Cesare Indiveri,
| |
Collapse
|
14
|
Structural basis for substrate specificity of heteromeric transporters of neutral amino acids. Proc Natl Acad Sci U S A 2021; 118:2113573118. [PMID: 34848541 DOI: 10.1073/pnas.2113573118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2021] [Indexed: 11/18/2022] Open
Abstract
Despite having similar structures, each member of the heteromeric amino acid transporter (HAT) family shows exquisite preference for the exchange of certain amino acids. Substrate specificity determines the physiological function of each HAT and their role in human diseases. However, HAT transport preference for some amino acids over others is not yet fully understood. Using cryo-electron microscopy of apo human LAT2/CD98hc and a multidisciplinary approach, we elucidate key molecular determinants governing neutral amino acid specificity in HATs. A few residues in the substrate-binding pocket determine substrate preference. Here, we describe mutations that interconvert the substrate profiles of LAT2/CD98hc, LAT1/CD98hc, and Asc1/CD98hc. In addition, a region far from the substrate-binding pocket critically influences the conformation of the substrate-binding site and substrate preference. This region accumulates mutations that alter substrate specificity and cause hearing loss and cataracts. Here, we uncover molecular mechanisms governing substrate specificity within the HAT family of neutral amino acid transporters and provide the structural bases for mutations in LAT2/CD98hc that alter substrate specificity and that are associated with several pathologies.
Collapse
|
15
|
Chemical Approaches for Studying the Biology and Pharmacology of Membrane Transporters: The Histidine/Large Amino Acid Transporter SLC7A5 as a Benchmark. Molecules 2021; 26:molecules26216562. [PMID: 34770970 PMCID: PMC8588388 DOI: 10.3390/molecules26216562] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 11/17/2022] Open
Abstract
The localization of membrane transporters at the forefront of natural barriers makes these proteins very interesting due to their involvement in the absorption and distribution of nutrients and xenobiotics, including drugs. Over the years, structure/function relationship studies have been performed employing several strategies, including chemical modification of exposed amino acid residues. These approaches are very meaningful when applied to membrane transporters, given that these proteins are characterized by both hydrophobic and hydrophilic domains with a different degree of accessibility to employed chemicals. Besides basic features, the chemical targeting approaches can disclose information useful for pharmacological applications as well. An eminent example of this picture is the histidine/large amino acid transporter SLC7A5, known as LAT1 (Large Amino Acid Transporter 1). This protein is crucial in cell life because it is responsible for mediating the absorption and distribution of essential amino acids in peculiar body districts, such as the blood brain barrier and placenta. Furthermore, LAT1 can recognize a large variety of molecules of pharmacological interest and is also considered a hot target for drugs due to its over-expression in virtually all human cancers. Therefore, it is not surprising that the chemical targeting approach, coupled with bioinformatics, site-directed mutagenesis and transport assays, proved fundamental in describing features of LAT1 such as the substrate binding site, regulatory domains and interactions with drugs that will be discussed in this review. The results on LAT1 can be considered to have general applicability to other transporters linked with human diseases.
Collapse
|
16
|
Pichia pastoris and the Recombinant Human Heterodimeric Amino Acid Transporter 4F2hc-LAT1: From Clone Selection to Pure Protein. Methods Protoc 2021; 4:mps4030051. [PMID: 34449687 PMCID: PMC8396027 DOI: 10.3390/mps4030051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/20/2021] [Accepted: 07/21/2021] [Indexed: 12/12/2022] Open
Abstract
Heterodimeric amino acid transporters (HATs) are protein complexes composed of two subunits, a heavy and a light subunit belonging to the solute carrier (SLC) families SLC3 and SLC7. HATs transport amino acids and derivatives thereof across the plasma membrane. The human HAT 4F2hc-LAT1 is composed of the type-II membrane N-glycoprotein 4F2hc (SLC3A2) and the L-type amino acid transporter LAT1 (SLC7A5). 4F2hc-LAT1 is medically relevant, and its dysfunction and overexpression are associated with autism and tumor progression. Here, we provide a general applicable protocol on how to screen for the best membrane transport protein-expressing clone in terms of protein amount and function using Pichia pastoris as expression host. Furthermore, we describe an overexpression and purification procedure for the production of the HAT 4F2hc-LAT1. The isolated heterodimeric complex is pure, correctly assembled, stable, binds the substrate L-leucine, and is thus properly folded. Therefore, this Pichia pastoris-derived recombinant human 4F2hc-LAT1 sample can be used for downstream biochemical and biophysical characterizations.
Collapse
|
17
|
Kantipudi S, Fotiadis D. Yeast Cell-Based Transport Assay for the Functional Characterization of Human 4F2hc-LAT1 and -LAT2, and LAT1 and LAT2 Substrates and Inhibitors. Front Mol Biosci 2021; 8:676854. [PMID: 34124158 PMCID: PMC8193492 DOI: 10.3389/fmolb.2021.676854] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 05/06/2021] [Indexed: 01/04/2023] Open
Abstract
In mammalian cells, the L-type amino acid transporters (LATs) LAT1 (SLC7A5) and LAT2 (SLC7A8) form heterodimeric amino acid transporters (HATs) with the ancillary protein 4F2hc and are involved in the cellular uptake of specific amino acids. The HAT 4F2hc-LAT1 is found upregulated in various cancer cell types, while 4F2hc-LAT2 is a transporter for non-cancer cells. Preclinical studies have highlighted that 4F2hc-LAT1 plays an important role in tumor progression representing a valid anticancer target. Consequently, current research is focusing on the development of potent and specific human 4F2hc-LAT1 inhibitors. On the other hand, 4F2hc-LAT2 is emerging as target of other diseases, thus also gaining clinical interest. To determine affinity and specificity of substrates and inhibitors for 4F2hc-LAT1 or 4F2hc-LAT2, robust transport cell assays are indispensable. We have optimized and validated a transport assay using cells of the methylotrophic yeast Pichia pastoris stably overexpressing the human HATs 4F2hc-LAT1 or -LAT2, and the LATs LAT1 or LAT2 alone. The radioligand [3H]L-leucine was used as reporter and the substrates L-leucine, triiodothyronine (T3) and thyroxine (T4) as well as the inhibitors BCH and JPH203 (KYT-0353) for assay validation. Obtained half-maximal inhibitory concentrations also provided new insights, e.g., into the LAT specificity of the potent inhibitor JPH203 and on the potency of the thyroid hormones T3 and T4 to inhibit transport through human 4F2hc-LAT2. The LAT1 and LAT2 assays are of particular interest to determine possible implications and influences of 4F2hc in ligand binding and transport. In summary, the presented assays are valuable for characterization of ligands, e.g., towards 4F2hc-LAT1 specificity, and can also be applied for compound screening. Finally, our established approach and assay would also be applicable to other HATs and LATs of interest.
Collapse
Affiliation(s)
- Satish Kantipudi
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Dimitrios Fotiadis
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| |
Collapse
|
18
|
Errasti-Murugarren E, Bartoccioni P, Palacín M. Membrane Protein Stabilization Strategies for Structural and Functional Studies. MEMBRANES 2021; 11:membranes11020155. [PMID: 33671740 PMCID: PMC7926488 DOI: 10.3390/membranes11020155] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 02/15/2021] [Accepted: 02/18/2021] [Indexed: 02/07/2023]
Abstract
Accounting for nearly two-thirds of known druggable targets, membrane proteins are highly relevant for cell physiology and pharmacology. In this regard, the structural determination of pharmacologically relevant targets would facilitate the intelligent design of new drugs. The structural biology of membrane proteins is a field experiencing significant growth as a result of the development of new strategies for structure determination. However, membrane protein preparation for structural studies continues to be a limiting step in many cases due to the inherent instability of these molecules in non-native membrane environments. This review describes the approaches that have been developed to improve membrane protein stability. Membrane protein mutagenesis, detergent selection, lipid membrane mimics, antibodies, and ligands are described in this review as approaches to facilitate the production of purified and stable membrane proteins of interest for structural and functional studies.
Collapse
Affiliation(s)
- Ekaitz Errasti-Murugarren
- Laboratory of Amino acid Transporters and Disease, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, 08028 Barcelona, Spain;
- CIBERER (Centro Español en Red de Biomedicina de Enfermedades Raras), 28029 Barcelona, Spain
- Correspondence: (E.E.-M.); (M.P.)
| | - Paola Bartoccioni
- Laboratory of Amino acid Transporters and Disease, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, 08028 Barcelona, Spain;
- CIBERER (Centro Español en Red de Biomedicina de Enfermedades Raras), 28029 Barcelona, Spain
| | - Manuel Palacín
- Laboratory of Amino acid Transporters and Disease, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, 08028 Barcelona, Spain;
- CIBERER (Centro Español en Red de Biomedicina de Enfermedades Raras), 28029 Barcelona, Spain
- Department of Biochemistry and Molecular Biomedicine, Universitat de Barcelona, 08028 Barcelona, Spain
- Correspondence: (E.E.-M.); (M.P.)
| |
Collapse
|
19
|
Granitzer S, Widhalm R, Forsthuber M, Ellinger I, Desoye G, Hengstschläger M, Zeisler H, Salzer H, Gundacker C. Amino Acid Transporter LAT1 (SLC7A5) Mediates MeHg-Induced Oxidative Stress Defense in the Human Placental Cell Line HTR-8/SVneo. Int J Mol Sci 2021; 22:ijms22041707. [PMID: 33567754 PMCID: PMC7915079 DOI: 10.3390/ijms22041707] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/02/2021] [Accepted: 02/05/2021] [Indexed: 12/25/2022] Open
Abstract
The placental barrier can protect the fetus from contact with harmful substances. The potent neurotoxin methylmercury (MeHg), however, is very efficiently transported across the placenta. Our previous data suggested that L-type amino acid transporter (LAT)1 is involved in placental MeHg uptake, accepting MeHg-L-cysteine conjugates as substrate due to structural similarity to methionine. The aim of the present study was to investigate the antioxidant defense of placental cells to MeHg exposure and the role of LAT1 in this response. When trophoblast-derived HTR-8/SVneo cells were LAT1 depleted by siRNA-mediated knockdown, they accumulated less MeHg. However, they were more susceptible to MeHg-induced toxicity. This was evidenced in decreased cell viability at a usually noncytotoxic concentration of 0.03 µM MeHg (~6 µg/L). Treatment with ≥0.3 µM MeHg increased cytotoxicity, apoptosis rate, and oxidative stress of HTR-8/SVneo cells. These effects were enhanced under LAT1 knockdown. Reduced cell number was seen when MeHg-exposed cells were cultured in medium low in cysteine, a constituent of the tripeptide glutathione (GSH). Because LAT1-deficient HTR-8/SVneo cells have lower GSH levels than control cells (independent of MeHg treatment), we conclude that LAT1 is essential for de novo synthesis of GSH, required to counteract oxidative stress. Genetic predisposition to decreased LAT1 function combined with MeHg exposure could increase the risk of placental damage.
Collapse
Affiliation(s)
- Sebastian Granitzer
- Karl-Landsteiner Private University for Health Sciences, A-3500 Krems, Austria; (S.G.); (R.W.)
- Institute of Medical Genetics, Medical University of Vienna, A-1090 Vienna, Austria; (M.F.); (M.H.)
| | - Raimund Widhalm
- Karl-Landsteiner Private University for Health Sciences, A-3500 Krems, Austria; (S.G.); (R.W.)
- Institute of Medical Genetics, Medical University of Vienna, A-1090 Vienna, Austria; (M.F.); (M.H.)
| | - Martin Forsthuber
- Institute of Medical Genetics, Medical University of Vienna, A-1090 Vienna, Austria; (M.F.); (M.H.)
| | - Isabella Ellinger
- Department of Pathophysiology and Allergy Research, Medical University of Vienna, A-1090 Vienna, Austria;
| | - Gernot Desoye
- Department of Obstetrics and Gynecology, Medical University of Graz, A-8036 Graz, Austria;
| | - Markus Hengstschläger
- Institute of Medical Genetics, Medical University of Vienna, A-1090 Vienna, Austria; (M.F.); (M.H.)
| | - Harald Zeisler
- Department of Obstetrics and Gynecology, Medical University Vienna, A-1090 Vienna, Austria;
| | - Hans Salzer
- Clinical Department of Pediatrics and Adolescent Medicine, University Hospital Tulln, A-3430 Tulln, Austria;
| | - Claudia Gundacker
- Institute of Medical Genetics, Medical University of Vienna, A-1090 Vienna, Austria; (M.F.); (M.H.)
- Correspondence: ; Tel.: +43-1-40160-56503
| |
Collapse
|
20
|
Wei Z, Liu X, Cheng C, Yu W, Yi P. Metabolism of Amino Acids in Cancer. Front Cell Dev Biol 2021; 8:603837. [PMID: 33511116 PMCID: PMC7835483 DOI: 10.3389/fcell.2020.603837] [Citation(s) in RCA: 168] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 11/30/2020] [Indexed: 12/13/2022] Open
Abstract
Metabolic reprogramming has been widely recognized as a hallmark of malignancy. The uptake and metabolism of amino acids are aberrantly upregulated in many cancers that display addiction to particular amino acids. Amino acids facilitate the survival and proliferation of cancer cells under genotoxic, oxidative, and nutritional stress. Thus, targeting amino acid metabolism is becoming a potential therapeutic strategy for cancer patients. In this review, we will systematically summarize the recent progress of amino acid metabolism in malignancy and discuss their interconnection with mammalian target of rapamycin complex 1 (mTORC1) signaling, epigenetic modification, tumor growth and immunity, and ferroptosis. Finally, we will highlight the potential therapeutic applications.
Collapse
Affiliation(s)
- Zhen Wei
- Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Medicine, Brain Science and Advanced Technology Institute, Wuhan University of Science and Technology, Wuhan, China
| | - Xiaoyi Liu
- Department of Obstetrics and Gynecology, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Chunming Cheng
- Department of Radiation Oncology, James Comprehensive Cancer Center and College of Medicine at The Ohio State University, Columbus, OH, United States
| | - Wei Yu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Ping Yi
- Department of Obstetrics and Gynecology, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, China
| |
Collapse
|