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Ni M, Yue Z, Tian M, Luo X, Wang W, Shi H, Luo J, Deng L, Li C. Leucine-Mediated SLC7A5 Promotes Milk Protein and Milk Fat Synthesis through mTOR Signaling Pathway in Goat Mammary Epithelial Cells. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:13728-13739. [PMID: 38807030 PMCID: PMC11192034 DOI: 10.1021/acs.jafc.4c02087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/18/2024] [Accepted: 05/22/2024] [Indexed: 05/30/2024]
Abstract
The SLC7A5 gene encodes a Na+ and pH-independent transporter protein that regulates cell growth by regulating the uptake of AA. This study, utilizing RNA-seq, aimed to explore the effect of SLC7A5 on the synthesis of milk proteins and fats in goat mammary epithelial cells (GMECs) through gene interference and overexpression techniques. The results demonstrated that the overexpression of SLC7A5 resulted in a significant increase in the expression of CSN1S1, SCD, CEBPB, ACACA, αS1-casein, p-S6K, and p-S6. The levels of p-S6K and p-S6 gradually increased as the AA/Leu stimulation time lengthened. The overexpression of SLC7A5 rescued the role of Torin1 in GMECs. In conclusion, SLC7A5 plays a crucial role in promoting the synthesis of milk proteins and milk fats through the mTOR signaling pathway in GMECs, providing a theoretical foundation for improving the quality of goat milk.
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Affiliation(s)
- Mengke Ni
- College of Animal Science
and Technology, Northwest A&F University, Yangling 712100, China
| | - Ziting Yue
- College of Animal Science
and Technology, Northwest A&F University, Yangling 712100, China
| | - Min Tian
- College of Animal Science
and Technology, Northwest A&F University, Yangling 712100, China
| | - Xinran Luo
- College of Animal Science
and Technology, Northwest A&F University, Yangling 712100, China
| | - Wanting Wang
- College of Animal Science
and Technology, Northwest A&F University, Yangling 712100, China
| | - Huaiping Shi
- College of Animal Science
and Technology, Northwest A&F University, Yangling 712100, China
| | - Jun Luo
- College of Animal Science
and Technology, Northwest A&F University, Yangling 712100, China
| | - Lu Deng
- College of Animal Science
and Technology, Northwest A&F University, Yangling 712100, China
| | - Cong Li
- College of Animal Science
and Technology, Northwest A&F University, Yangling 712100, China
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2
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Lee B, Lee SY, Han DH, Park HD. Interpretation of SLC3A1 and SLC7A9 variants in cystinuria patients: The significance of the PM3 criterion and protein stability. Urolithiasis 2023; 51:94. [PMID: 37439839 PMCID: PMC10345071 DOI: 10.1007/s00240-023-01466-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 06/27/2023] [Indexed: 07/14/2023]
Abstract
Cystinuria is a genetic disorder caused by defects in the b0,+ transporter system, which is composed of rBAT and b0,+AT coded by SLC3A1 and SLC7A9, respectively. Variants in SLC3A1 and SLC7A9 follow autosomal recessive inheritance and autosomal dominant inheritance with reduced penetrance, respectively, which complicates the interpretation of cystinuria-related variants. Here, we report seven different SLC3A1 variants and six different SLC7A9 variants. Among these variants were two novel variants previously not reported: SLC3A1 c.223C > T and SLC7A9 c.404A > G. In silico analysis using REVEL correlated well with the functional loss upon SLC7A9 variants with scores of 0.8560-0.9200 and 0.4970-0.5239 for severe and mild decrease in transport activity, respectively. In addition, DynaMut2 was able to predict a decreased protein expression level resulting from the SLC7A9 variant c.313G > A with a ΔΔGStability -2.93 kcal/mol. Our study adds to the literature as additional cases of a variant allow applying the PM3 criterion with higher strength level. In addition, we suggest the clinical utility of REVEL and DynaMut2 in interpreting SLC3A1 and SLC7A9 variants. While a decreased protein expression level is not embraced in the current variant interpretation guidelines, we believe in silico protein stability predicting tools could serve as evidence of protein function loss.
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Affiliation(s)
- Beomki Lee
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, Korea
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Soo-Youn Lee
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, Korea
| | - Deok Hyun Han
- Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, Korea.
| | - Hyung-Doo Park
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, Korea.
- Department of Medical Device Management and Research, SAIHST, Sungkyunkwan University, Seoul, 06355, Korea.
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3
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Clinical Characteristics and In Silico Analysis of Cystinuria Caused by a Novel SLC3A1 Mutation. Genes (Basel) 2022; 13:genes13112173. [DOI: 10.3390/genes13112173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/27/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022] Open
Abstract
Cystinuria is a genetically inherited disorder of renal and intestinal transport, featured as a high concentration of cystine in the urine. Cumulative cystine in urine would cause the formation of kidney stones, which further leads to renal colic and dysfunction. Gene screens have found that mutations in SLC3A1 or SLC7A9 gene are responsible for most cases of cystinuria, for encoding defective cystine transporters. Here, we presented the genotypic and phenotypic characteristics of one unique case of a three-generation Chinese family. The proband developed severe urolithiasis combined with renal damage. The radiography and computed tomography (CT) scan showed calculus in the left pelvic kidney. Postoperative stone analysis revealed that the stones were mainly composed of cystine. Therefore, to explore its pathogenesis, next-generation Whole Exome Sequencing (WES) and Sanger sequencing identify the proband mutated gene of the proband’s family. In this article, we reported novel compound heterozygous mutations (c.818G>A and c.1011G>A) of the SLC3A1 gene in a 5-year-old child suffering from a cystine stone from a three-generation family. Bioinformatic analysis was used to predict the pathogenicity and conservation of the target mutation. Conservative sequence and evolutionary conservation analysis indicated that cystine273 and proline337 were highly conserved among species, and both mutations listed here (Cys273Tyr and Pro337Pro) were pathogenic. To conclude, our study expands the phenotypic and genotypic spectrum of SLC3A1 and indicates that genetic screening should be considered in the clinic to provide more effective and precise treatment for cystinuria.
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4
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Cibrian D, Baixauli F, Palacin M. Editorial: Amino Acid Transport and Metabolism During Homeostasis and Inflammation. Front Immunol 2022; 12:833258. [PMID: 35111170 PMCID: PMC8801421 DOI: 10.3389/fimmu.2021.833258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 12/29/2021] [Indexed: 11/18/2022] Open
Affiliation(s)
- Danay Cibrian
- Vascular Pathophysiology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Francesc Baixauli
- Department of Immunometabolism, Max Planck Institute for Immunobiology and Epigenetics, Freiburg, Germany
| | - Manuel Palacin
- Institute for Research in Biomedicine (IRB-Barcelona) within the Barcelona Institute of Science and Technology (BIST), U731 CIBERER and Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Barcelona, Spain
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5
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Yair S, Lee KM, Coop G. The timing of human adaptation from Neanderthal introgression. Genetics 2021; 218:iyab052. [PMID: 33787889 PMCID: PMC8128397 DOI: 10.1093/genetics/iyab052] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 02/26/2021] [Indexed: 12/26/2022] Open
Abstract
Admixture has the potential to facilitate adaptation by providing alleles that are immediately adaptive in a new environment or by simply increasing the long-term reservoir of genetic diversity for future adaptation. A growing number of cases of adaptive introgression are being identified in species across the tree of life, however the timing of selection, and therefore the importance of the different evolutionary roles of admixture, is typically unknown. Here, we investigate the spatio-temporal history of selection favoring Neanderthal-introgressed alleles in modern human populations. Using both ancient and present-day samples of modern humans, we integrate the known demographic history of populations, namely population divergence and migration, with tests for selection. We model how a sweep placed along different branches of an admixture graph acts to modify the variance and covariance in neutral allele frequencies among populations at linked loci. Using a method based on this model of allele frequencies, we study previously identified cases of adaptive Neanderthal introgression. From these, we identify cases in which Neanderthal-introgressed alleles were quickly beneficial and other cases in which they persisted at low frequency for some time. For some of the alleles that persisted at low frequency, we show that selection likely independently favored them later on in geographically separated populations. Our work highlights how admixture with ancient hominins has contributed to modern human adaptation and contextualizes observed levels of Neanderthal ancestry in present-day and ancient samples.
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Affiliation(s)
- Sivan Yair
- Center for Population Biology, University of California, Davis, Davis, CA 95616, USA
- Department of Evolution and Ecology, University of California, Davis, Davis, CA 95616, USA
| | - Kristin M Lee
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Graham Coop
- Center for Population Biology, University of California, Davis, Davis, CA 95616, USA
- Department of Evolution and Ecology, University of California, Davis, Davis, CA 95616, USA
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6
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Morio H, Reien Y, Hirayama Y, Hashimoto H, Anzai N. Protein kinase C activation upregulates human L-type amino acid transporter 2 function. J Physiol Sci 2021; 71:11. [PMID: 33789576 PMCID: PMC10716992 DOI: 10.1186/s12576-021-00795-0] [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: 10/13/2020] [Accepted: 03/05/2021] [Indexed: 11/10/2022]
Abstract
L-type amino acid transporter 2 (LAT2) is a Na+-independent neutral amino acid transporter, whose function regulation system remains unclarified. Since protein kinase C (PKC) is known to regulate the functions of various transporters, we investigated whether human LAT2 (hLAT2) function is regulated by PKC. In mouse proximal tubule S2 cells, hLAT2 transport activity was upregulated by PKC activation. However, we found that the mRNA and protein expression of hLAT2 was not affected by PKC activation and that the upregulation was independent of the three potential PKC consensus sites in the hLAT2 amino acid sequence. Moreover, we found that PKC activation upregulated the Vmax value for hLAT2-mediated alanine transport, which was not accompanied by the induction of hLAT2 membrane insertion. In conclusion, we showed that hLAT2 function is upregulated by PKC activation, which is not related to either the de novo synthesis, the phosphorylation or the membrane insertion of hLAT2.
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Affiliation(s)
- Hanae Morio
- Department of Pharmacology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuou-ku, Chiba, 260-8670, Japan
| | - Yoshie Reien
- Department of Pharmacology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuou-ku, Chiba, 260-8670, Japan
| | - Yuri Hirayama
- Department of Pharmacology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuou-ku, Chiba, 260-8670, Japan
| | - Hirofumi Hashimoto
- Department of Pharmacology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuou-ku, Chiba, 260-8670, Japan
| | - Naohiko Anzai
- Department of Pharmacology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuou-ku, Chiba, 260-8670, Japan.
- Department of Pharmacology and Toxicology, School of Medicine, Dokkyo Medical University, 880 Kitakobayashi, Mibu-cho, Shimotsuga-gun, Tochigi, 321-0293, Japan.
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7
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Fairweather SJ, Shah N, Brӧer S. Heteromeric Solute Carriers: Function, Structure, Pathology and Pharmacology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 21:13-127. [PMID: 33052588 DOI: 10.1007/5584_2020_584] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Solute carriers form one of three major superfamilies of membrane transporters in humans, and include uniporters, exchangers and symporters. Following several decades of molecular characterisation, multiple solute carriers that form obligatory heteromers with unrelated subunits are emerging as a distinctive principle of membrane transporter assembly. Here we comprehensively review experimentally established heteromeric solute carriers: SLC3-SLC7 amino acid exchangers, SLC16 monocarboxylate/H+ symporters and basigin/embigin, SLC4A1 (AE1) and glycophorin A exchanger, SLC51 heteromer Ost α-Ost β uniporter, and SLC6 heteromeric symporters. The review covers the history of the heteromer discovery, transporter physiology, structure, disease associations and pharmacology - all with a focus on the heteromeric assembly. The cellular locations, requirements for complex formation, and the functional role of dimerization are extensively detailed, including analysis of the first complete heteromer structures, the SLC7-SLC3 family transporters LAT1-4F2hc, b0,+AT-rBAT and the SLC6 family heteromer B0AT1-ACE2. We present a systematic analysis of the structural and functional aspects of heteromeric solute carriers and conclude with common principles of their functional roles and structural architecture.
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Affiliation(s)
- Stephen J Fairweather
- Research School of Biology, Australian National University, Canberra, ACT, Australia. .,Resarch School of Chemistry, Australian National University, Canberra, ACT, Australia.
| | - Nishank Shah
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Stefan Brӧer
- Research School of Biology, Australian National University, Canberra, ACT, Australia.
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8
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Transport of L-Arginine Related Cardiovascular Risk Markers. J Clin Med 2020; 9:jcm9123975. [PMID: 33302555 PMCID: PMC7764698 DOI: 10.3390/jcm9123975] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 12/15/2022] Open
Abstract
L-arginine and its derivatives, asymmetric and symmetric dimethylarginine (ADMA and SDMA) and L-homoarginine, have emerged as cardiovascular biomarkers linked to cardiovascular outcomes and various metabolic and functional pathways such as NO-mediated endothelial function. Cellular uptake and efflux of L-arginine and its derivatives are facilitated by transport proteins. In this respect the cationic amino acid transporters CAT1 and CAT2 (SLC7A1 and SLC7A2) and the system y+L amino acid transporters (SLC7A6 and SLC7A7) have been most extensively investigated, so far, but the number of transporters shown to mediate the transport of L-arginine and its derivatives is constantly increasing. In the present review we assess the growing body of evidence regarding the function, expression, and clinical relevance of these transporters and their possible relation to cardiovascular diseases.
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9
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Oda K, Lee Y, Wiriyasermkul P, Tanaka Y, Takemoto M, Yamashita K, Nagamori S, Nishizawa T, Nureki O. Consensus mutagenesis approach improves the thermal stability of system x c - transporter, xCT, and enables cryo-EM analyses. Protein Sci 2020; 29:2398-2407. [PMID: 33016372 PMCID: PMC7679960 DOI: 10.1002/pro.3966] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 09/26/2020] [Accepted: 09/29/2020] [Indexed: 12/20/2022]
Abstract
System xc− is an amino acid antiporter that imports L‐cystine into cells and exports intracellular L‐glutamate, at a 1:1 ratio. As L‐cystine is an essential precursor for glutathione synthesis, system xc− supports tumor cell growth through glutathione‐based oxidative stress resistance and is considered as a potential therapeutic target for cancer treatment. System xc− consists of two subunits, the light chain subunit SLC7A11 (xCT) and the heavy chain subunit SLC3A2 (also known as CD98hc or 4F2hc), which are linked by a conserved disulfide bridge. Although the recent structures of another SLC7 member, L‐type amino acid transporter 1 (LAT1) in complex with CD98hc, have provided the structural basis toward understanding the amino acid transport mechanism, the detailed molecular mechanism of xCT remains unknown. To revealthe molecular mechanism, we performed single‐particle analyses of the xCT‐CD98hc complex. As wild‐type xCT‐CD98hc displayed poor stability and could not be purified to homogeneity, we applied a consensus mutagenesis approach to xCT. The consensus mutated construct exhibited increased stability as compared to the wild‐type, and enabled the cryoelectron microscopy (cryo‐EM) map to be obtained at 6.2 Å resolution by single‐particle analysis. The cryo‐EM map revealed sufficient electron density to assign secondary structures. In the xCT structure, the hash and arm domains are well resolved, whereas the bundle domain shows some flexibility. CD98hc is positioned next to the xCT transmembrane domain. This study provides the structural basis of xCT, and our consensus‐based strategy could represent a good choice toward solving unstable protein structures.
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Affiliation(s)
- Kazumasa Oda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan
| | - Yongchan Lee
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Pattama Wiriyasermkul
- Department of Collaborative Research for Bio-Molecular Dynamics, Nara Medical University, Nara, Japan
| | - Yoko Tanaka
- Department of Collaborative Research for Bio-Molecular Dynamics, Nara Medical University, Nara, Japan
| | - Mizuki Takemoto
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan
| | - Keitaro Yamashita
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan
| | - Shushi Nagamori
- Department of Collaborative Research for Bio-Molecular Dynamics, Nara Medical University, Nara, Japan
| | - Tomohiro Nishizawa
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan
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10
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Structural basis for amino acid exchange by a human heteromeric amino acid transporter. Proc Natl Acad Sci U S A 2020; 117:21281-21287. [PMID: 32817565 DOI: 10.1073/pnas.2008111117] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Heteromeric amino acid transporters (HATs) comprise a group of membrane proteins that belong to the solute carrier (SLC) superfamily. They are formed by two different protein components: a light chain subunit from an SLC7 family member and a heavy chain subunit from the SLC3 family. The light chain constitutes the transport subunit whereas the heavy chain mediates trafficking to the plasma membrane and maturation of the functional complex. Mutation, malfunction, and dysregulation of HATs are associated with a wide range of pathologies or represent the direct cause of inherited and acquired disorders. Here we report the cryogenic electron microscopy structure of the neutral and basic amino acid transport complex (b[0,+]AT1-rBAT) which reveals a heterotetrameric protein assembly composed of two heavy and light chain subunits, respectively. The previously uncharacterized interaction between two HAT units is mediated via dimerization of the heavy chain subunits and does not include participation of the light chain subunits. The b(0,+)AT1 transporter adopts a LeuT fold and is captured in an inward-facing conformation. We identify an amino-acid-binding pocket that is formed by transmembrane helices 1, 6, and 10 and conserved among SLC7 transporters.
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11
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Metabolic Pathways That Control Skin Homeostasis and Inflammation. Trends Mol Med 2020; 26:975-986. [PMID: 32371170 DOI: 10.1016/j.molmed.2020.04.004] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 04/03/2020] [Accepted: 04/08/2020] [Indexed: 12/27/2022]
Abstract
Keratinocytes and skin immune cells are actively metabolizing nutrients present in their microenvironment. This is particularly important in common chronic inflammatory skin diseases such as psoriasis and atopic dermatitis, characterized by hyperproliferation of keratinocytes and expansion of inflammatory cells, thus suggesting increased cell nutritional requirements. Proliferating inflammatory cells and keratinocytes express high levels of glucose transporter (GLUT)1, l-type amino acid transporter (LAT)1, and cationic amino acid transporters (CATs). Main metabolic regulators such as hypoxia-inducible factor (HIF)-1α, MYC, and mechanistic target of rapamycin (mTOR) control immune cell activation, proliferation, and cytokine release. Here, we provide an updated perspective regarding the potential role of nutrient transporters and metabolic pathways that could be common to immune cells and keratinocytes, to control psoriasis and atopic dermatitis.
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12
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Yan R, Li Y, Shi Y, Zhou J, Lei J, Huang J, Zhou Q. Cryo-EM structure of the human heteromeric amino acid transporter b 0,+AT-rBAT. SCIENCE ADVANCES 2020; 6:eaay6379. [PMID: 32494597 PMCID: PMC7159911 DOI: 10.1126/sciadv.aay6379] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 01/22/2020] [Indexed: 05/16/2023]
Abstract
Heteromeric amino acid transporters (HATs) catalyze the transmembrane movement of amino acids, comprising two subunits, a heavy chain and a light chain, linked by a disulfide bridge. The b0,+AT (SLC7A9) is a representative light chain of HATs, forming heterodimer with rBAT, a heavy chain which mediates the membrane trafficking of b0,+AT. The b0,+AT-rBAT complex is an obligatory exchanger, which mediates the influx of cystine and cationic amino acids and the efflux of neutral amino acids in kidney and small intestine. Here, we report the cryo-EM structure of the human b0,+AT-rBAT complex alone and in complex with arginine substrate at resolution of 2.7 and 2.3 Å, respectively. The overall structure of b0,+AT-rBAT exists as a dimer of heterodimer consistent with the previous study. A ligand molecule is bound to the substrate binding pocket, near which an occluded pocket is identified, to which we found that it is important for substrate transport.
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Affiliation(s)
- Renhong Yan
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Yaning Li
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yi Shi
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Jiayao Zhou
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jianlin Lei
- Technology Center for Protein Sciences, Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jing Huang
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Qiang Zhou
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
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13
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Asc-1 Transporter (SLC7A10): Homology Models And Molecular Dynamics Insights Into The First Steps Of The Transport Mechanism. Sci Rep 2020; 10:3731. [PMID: 32111919 PMCID: PMC7048771 DOI: 10.1038/s41598-020-60617-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 02/14/2020] [Indexed: 12/02/2022] Open
Abstract
The alanine-serine-cysteine transporter Asc-1 regulates the synaptic availability of d-serine and glycine (the two co-agonists of the NMDA receptor) and is regarded as an important drug target. To shuttle the substrate from the extracellular space to the cytoplasm, this transporter undergoes multiple distinct conformational states. In this work, homology modeling, substrate docking and molecular dynamics simulations were carried out to learn more about the transition between the “outward-open” and “outward-open occluded” states. We identified a transition state involving the highly-conserved unwound TM6 region in which the Phe243 flips close to the d-serine substrate without major movements of TM6. This feature and those of other key residues are proposed to control the binding site and substrate translocation. Competitive inhibitors ACPP, LuAE00527 and SMLC were docked and their binding modes at the substrate binding site corroborated the key role played by Phe243 of TM6. For ACPP and LuAE00527, strong hydrophobic interactions with this residue hinder its mobility and prevent the uptake and the efflux of substrates. As for SMLC, the weaker interactions maintain the flexibility of Phe243 and the efflux process. Overall, we propose a molecular basis for the inhibition of substrate translocation of the Asc-1 transporter that should be valuable for rational drug design.
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14
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Patel D, Kharkar PS, Gandhi NS, Kaur E, Dutt S, Nandave M. Novel analogs of sulfasalazine as system x c - antiporter inhibitors: Insights from the molecular modeling studies. Drug Dev Res 2019; 80:758-777. [PMID: 31199023 DOI: 10.1002/ddr.21557] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 04/16/2019] [Accepted: 05/27/2019] [Indexed: 02/05/2023]
Abstract
System xc - (Sxc - ), a cystine-glutamate antiporter, is established as an interesting target for the treatment of several pathologies including epileptic seizures, glioma, neurodegenerative diseases, and multiple sclerosis. Erastin, sorafenib, and sulfasalazine (SSZ) are a few of the established inhibitors of Sxc - . However, its pharmacological inhibition with novel and potent agents is still very much required due to potential issues, for example, potency, bioavailability, and blood-brain barrier (BBB) permeability, with the current lead molecules such as SSZ. Therefore, in this study, we report the synthesis and structure-activity relationships (SAR) of SSZ derivatives along with molecular docking and dynamics simulations using the developed homology model of xCT chain of Sxc - antiporter. The generated homology model attempted to address the limitations of previously reported comparative protein models, thereby increasing the confidence in the computational modeling studies. The main objective of the present study was to derive a suitable lead structure from SSZ eliminating its potential issues for the treatment of glioblastoma multiforme (GBM), a deadly and malignant grade IV astrocytoma. The designed compounds with favorable Sxc - inhibitory activity following in vitro Sxc - inhibition studies, showed moderately potent cytotoxicity in patient-derived human glioblastoma cells, thereby generating potential interest in these compounds. The xCT-ligand model can be further optimized in search of potent lead molecules for novel drug discovery and development studies.
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Affiliation(s)
- Dhavalkumar Patel
- Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, SVKM's NMIMS (Deemed to be University), Vile Parle (West), Mumbai, Maharashtra, India
| | - Prashant S Kharkar
- Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, SVKM's NMIMS (Deemed to be University), Vile Parle (West), Mumbai, Maharashtra, India
| | - Neha S Gandhi
- School of Mathematical Sciences and Institute for Health and Biomedical Innovation, Queensland University of Technology, Gardens Point Campus, Brisbane, Queensland, Australia
| | - Ekjot Kaur
- Shilpee Dutt Laboratory, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, Maharashtra, India
| | - Shilpee Dutt
- Shilpee Dutt Laboratory, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, Maharashtra, India
| | - Mukesh Nandave
- Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, SVKM's NMIMS (Deemed to be University), Vile Parle (West), Mumbai, Maharashtra, India.,Department of Pharmacology, Delhi Pharmaceutical Sciences and Research University, New Delhi, India
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15
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Cryo-EM structure of the human L-type amino acid transporter 1 in complex with glycoprotein CD98hc. Nat Struct Mol Biol 2019; 26:510-517. [DOI: 10.1038/s41594-019-0237-7] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 04/26/2019] [Indexed: 02/07/2023]
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16
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Torrecillas IR, Conde-Ceide S, de Lucas AI, Garcı́a Molina A, Trabanco AA, Lavreysen H, Pardo L, Tresadern G. Inhibition of the Alanine-Serine-Cysteine-1 Transporter by BMS-466442. ACS Chem Neurosci 2019; 10:2510-2517. [PMID: 30821959 DOI: 10.1021/acschemneuro.9b00019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Experiment and modeling were combined to understand inhibition of the alanine-serine-cysteine-1 (asc1) transporter. The structure-activity relationship (SAR) was explored with synthesis of analogues of BMS-466442. Direct target interaction and binding site location between TM helices 6 and 10 were confirmed via site directed mutagenesis. Computational modeling suggested the inhibitor binds via competitive occupation of the orthosteric site while also blocking the movement of TM helices that are required for transport.
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Affiliation(s)
- Ivan R. Torrecillas
- Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina, Universitat Autonoma de Barcelona, 08193, Bellaterra, Spain
| | - Susana Conde-Ceide
- Medicinal Chemistry, Janssen Research & Development, Calle Jarama 75A, Toledo 45007, Spain
| | - Ana Isabel de Lucas
- Medicinal Chemistry, Janssen Research & Development, Calle Jarama 75A, Toledo 45007, Spain
| | | | - Andrés A. Trabanco
- Medicinal Chemistry, Janssen Research & Development, Calle Jarama 75A, Toledo 45007, Spain
| | | | - Leonardo Pardo
- Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina, Universitat Autonoma de Barcelona, 08193, Bellaterra, Spain
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17
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Transport of cystine across xC− antiporter. Arch Biochem Biophys 2019; 664:117-126. [DOI: 10.1016/j.abb.2019.01.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 01/30/2019] [Accepted: 01/31/2019] [Indexed: 01/17/2023]
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18
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Abstract
The small intestine mediates the absorption of amino acids after ingestion of protein and sustains the supply of amino acids to all tissues. The small intestine is an important contributor to plasma amino acid homeostasis, while amino acid transport in the large intestine is more relevant for bacterial metabolites and fluid secretion. A number of rare inherited disorders have contributed to the identification of amino acid transporters in epithelial cells of the small intestine, in particular cystinuria, lysinuric protein intolerance, Hartnup disorder, iminoglycinuria, and dicarboxylic aminoaciduria. These are most readily detected by analysis of urine amino acids, but typically also affect intestinal transport. The genes underlying these disorders have all been identified. The remaining transporters were identified through molecular cloning techniques to the extent that a comprehensive portrait of functional cooperation among transporters of intestinal epithelial cells is now available for both the basolateral and apical membranes. Mouse models of most intestinal transporters illustrate their contribution to amino acid homeostasis and systemic physiology. Intestinal amino acid transport activities can vary between species, but these can now be explained as differences of amino acid transporter distribution along the intestine. © 2019 American Physiological Society. Compr Physiol 9:343-373, 2019.
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Affiliation(s)
- Stefan Bröer
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Stephen J Fairweather
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
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19
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Bröer A, Fairweather S, Bröer S. Disruption of Amino Acid Homeostasis by Novel ASCT2 Inhibitors Involves Multiple Targets. Front Pharmacol 2018; 9:785. [PMID: 30072900 PMCID: PMC6060247 DOI: 10.3389/fphar.2018.00785] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 06/27/2018] [Indexed: 12/02/2022] Open
Abstract
The glutamine transporter ASCT2 (SLC1A5) is actively investigated as an oncological target, but the field lacks efficient ASCT2 inhibitors. A new group of ASCT2 inhibitors, 2-amino-4-bis(aryloxybenzyl)aminobutanoic acids (AABA), were developed recently and shown to suppress tumor growth in preclinical in vivo models. To test its specificity, we deleted ASCT2 in two human cancer cell lines. Surprisingly, growth of parental and ASCT2-knockout cells was equally sensitive to AABA compounds. AABA compounds inhibited glutamine transport in cells lacking ASCT2, but not in parental cells. Deletion of ASCT2 and amino acid (AA) depletion induced expression of SNAT2 (SLC38A2), the activity of which was inhibited by AABA compounds. They also potently inhibited isoleucine uptake via LAT1 (SLC7A5), a transporter that is upregulated in cancer cells together with ASCT2. Inhibition of SNAT2 and LAT1 was confirmed by recombinant expression in Xenopus laevis oocytes. The reported reduction of tumor growth in pre-clinical models may be explained by a significant disruption of AA homeostasis.
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Affiliation(s)
- Angelika Bröer
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Stephen Fairweather
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Stefan Bröer
- Research School of Biology, Australian National University, Canberra, ACT, Australia
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20
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Krause G, Hinz KM. Thyroid hormone transport across L-type amino acid transporters: What can molecular modelling tell us? Mol Cell Endocrinol 2017; 458:68-75. [PMID: 28341457 DOI: 10.1016/j.mce.2017.03.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/20/2017] [Accepted: 03/20/2017] [Indexed: 12/15/2022]
Abstract
Thyroid hormones (THs) and their derivatives require transmembrane transporters (TTs) to mediate their translocation across the cell membrane. Among these TTs, the L-type amino acid transporters (LAT) not only transport amino acids (AAs) but also certain THs and their derivatives. This review summarizes available knowledge concerning structure function patterns of the TH transport by LAT1 and LAT2. For example, LAT2 imports 3,3'-T2 and T3, but not rT3 and T4. In contrast to amino acids, THs are not at all exported by LAT2. Homology modelling of LAT1 and LAT2 is based on available crystal structures from the same superfamily the amino acid/polyamine/organocation transporter (APC). Molecular model guided mutagenesis has been used to predict substrate interaction sites. A common recognition feature for amino acid- and TH-derivatives has been suggested in an interior cavity of LAT1 and LAT2. Therein additional distinct molecular determinants that are responsible for the bidirectional AA transport but allowing only unidirectional import of particular THs have been confirmed for LAT2 by mutagenesis. Characterized substrate features that are needed for TH translocation and distinct LAT2 properties will be highlighted to understand the molecular import and export mechanisms of this transporter in more detail.
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Affiliation(s)
- Gerd Krause
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Berlin, Germany.
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21
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Abstract
Glycine, besides exerting essential metabolic functions, is an important inhibitory neurotransmitter in caudal areas of the central nervous system and also a positive neuromodulator at excitatory glutamate-mediated synapses. Glial cells provide metabolic support to neurons and modulate synaptic activity. Six transporters belonging to three solute carrier families (SLC6, SLC38, and SLC7) are capable of transporting glycine across the glial plasma membrane. The unique glial glycine-selective transporter GlyT1 (SLC6) is the main regulator of synaptic glycine concentrations, assisted by the neuronal GlyT2. The five additional glycine transporters ATB0,+, SNAT1, SNAT2, SNAT5, and LAT2 display broad amino acid specificity and have differential contributions to glial glycine transport. Glial glycine transporters are divergent in sequence but share a similar architecture displaying the 5 + 5 inverted fold originally characterized in the leucine transporter LeuT. The availability of protein crystals solved at high resolution for prokaryotic and, more recently, eukaryotic homologues of this superfamily has advanced significantly our understanding of the mechanism of glycine transport.
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