1
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Link CJ, Marques O, Knopf JD, Lemberg MK, Muckenthaler MU. E3 ubiquitin ligases SMURF1 and HECW1 regulate hepcidin-induced degradation of ferroportin in HeLa cells. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119803. [PMID: 39117288 DOI: 10.1016/j.bbamcr.2024.119803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 06/08/2024] [Accepted: 07/21/2024] [Indexed: 08/10/2024]
Affiliation(s)
- Camille J Link
- Heidelberg University, Medical Faculty Heidelberg, Department of Anesthesiology, Im Neuenheimer Feld 420, 69120 Heidelberg; Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Oriana Marques
- Department of Pediatric Hematology, Oncology and Immunology, University of Heidelberg, Heidelberg, Germany.; Molecular Medicine Partnership Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Julia D Knopf
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Marius K Lemberg
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany; Center for Biochemistry and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Martina U Muckenthaler
- Department of Pediatric Hematology, Oncology and Immunology, University of Heidelberg, Heidelberg, Germany.; Molecular Medicine Partnership Unit, European Molecular Biology Laboratory, Heidelberg, Germany; German Centre for Cardiovascular Research, Partner Site Heidelberg, Germany.; Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, Im Neuenheimer Feld 350, 69120 Heidelberg, Germany.
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2
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Ongey EL, Banerjee A. In vitro reconstitution of transition metal transporters. J Biol Chem 2024; 300:107589. [PMID: 39032653 PMCID: PMC11381811 DOI: 10.1016/j.jbc.2024.107589] [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: 02/24/2024] [Revised: 06/28/2024] [Accepted: 07/03/2024] [Indexed: 07/23/2024] Open
Abstract
Transition metal ions are critically important across all kingdoms of life. The chemical properties of iron, copper, zinc, manganese, cobalt, and nickel make them very attractive for use as cofactors in metalloenzymes and/or metalloproteins. Their versatile chemistry in aqueous solution enables them to function both as electron donors and acceptors, and thus participate in both reduction and oxidation reactions respectively. Transition metal ions can also function as nonredox multidentate coordination sites that play essential roles in macromolecular structure and function. Malfunction in transition metal transport and homeostasis has been linked to a wide number of human diseases including cancer, diabetes, and neurodegenerative disorders. Transition metal transporters are central players in the physiology of transition metals whereby they move transition metals in and out of cellular compartments. In this review, we provide a comprehensive overview of in vitro reconstitution of the activity of integral membrane transition metal transporters and discuss strategies that have been successfully implemented to overcome the challenges. We also discuss recent advances in our understanding of transition metal transport mechanisms and the techniques that are currently used to decipher the molecular basis of transport activities of these proteins. Deep mechanistic insights into transition metal transport systems will be essential to understand their malfunction in human diseases and target them for potential therapeutic strategies.
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Affiliation(s)
- Elvis L Ongey
- Cell Biology and Neurobiology Branch, National Institutes of Child Health and Human, Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Anirban Banerjee
- Cell Biology and Neurobiology Branch, National Institutes of Child Health and Human, Development, National Institutes of Health, Bethesda, Maryland, USA.
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3
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Uguen K, Le Tertre M, Tchernitchko D, Elbahnsi A, Maestri S, Gourlaouen I, Férec C, Ka C, Callebaut I, Le Gac G. The dual loss and gain of function of the FPN1 iron exporter results in the ferroportin disease phenotype. HGG ADVANCES 2024; 5:100335. [PMID: 39039793 PMCID: PMC11343060 DOI: 10.1016/j.xhgg.2024.100335] [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: 03/13/2024] [Revised: 07/16/2024] [Accepted: 07/16/2024] [Indexed: 07/24/2024] Open
Abstract
Heterozygous mutations in SLC40A1, encoding a multi-pass membrane protein of the major facilitator superfamily known as ferroportin 1 (FPN1), are responsible for two distinct hereditary iron-overload diseases: ferroportin disease, which is associated with reduced FPN1 activity (i.e., decrease in cellular iron export), and SLC40A1-related hemochromatosis, which is associated with abnormally high FPN1 activity (i.e., resistance to hepcidin). Here, we report three SLC40A1 missense variants with opposite functional consequences. In cultured cells, the p.Arg40Gln and p.Ser47Phe substitutions partially reduced the ability of FPN1 to export iron and also partially reduced its sensitivity to hepcidin. The p.Ala350Val substitution had more profound effects, resulting in low FPN1 iron egress and weak FPN1/hepcidin interaction. Structural analyses helped to differentiate the first two substitutions, which are predicted to cause local instabilities, and the third, which is thought to prevent critical rigid-body movements that are essential to the iron transport cycle. The phenotypic traits observed in a total of 12 affected individuals are highly suggestive of ferroportin disease. Our findings dismantle the classical dualism of FPN1 loss versus gain of function, highlight some specific and unexpected functions of FPN1 transmembrane helices in the molecular mechanism of iron export and its regulation by hepcidin, and extend the spectrum of rare genetic variants that may cause ferroportin disease.
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Affiliation(s)
- Kevin Uguen
- University Brest, Inserm, EFS, UMR 1078, GGB, 29200 Brest, France; CHU de Brest, 29200 Brest, France
| | - Marlène Le Tertre
- University Brest, Inserm, EFS, UMR 1078, GGB, 29200 Brest, France; CHU de Brest, 29200 Brest, France
| | - Dimitri Tchernitchko
- CHU Paris Nord-Val de Seine - Hôpital Xavier Bichat-Claude Bernard, 75018 Paris, France; Centre de Recherche sur l'Inflammation, Inserm U1149, 75018 Paris, France
| | - Ahmad Elbahnsi
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France
| | - Sandrine Maestri
- University Brest, Inserm, EFS, UMR 1078, GGB, 29200 Brest, France
| | | | - Claude Férec
- University Brest, Inserm, EFS, UMR 1078, GGB, 29200 Brest, France; CHU de Brest, 29200 Brest, France; Association Gaétan Saleün, 29200 Brest, France
| | - Chandran Ka
- University Brest, Inserm, EFS, UMR 1078, GGB, 29200 Brest, France; CHU de Brest, 29200 Brest, France; Laboratory of Excellence GR-Ex, 75015 Paris, France
| | - Isabelle Callebaut
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France
| | - Gérald Le Gac
- University Brest, Inserm, EFS, UMR 1078, GGB, 29200 Brest, France; CHU de Brest, 29200 Brest, France; Laboratory of Excellence GR-Ex, 75015 Paris, France.
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4
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Galy B, Conrad M, Muckenthaler M. Mechanisms controlling cellular and systemic iron homeostasis. Nat Rev Mol Cell Biol 2024; 25:133-155. [PMID: 37783783 DOI: 10.1038/s41580-023-00648-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 99.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2023] [Indexed: 10/04/2023]
Abstract
In mammals, hundreds of proteins use iron in a multitude of cellular functions, including vital processes such as mitochondrial respiration, gene regulation and DNA synthesis or repair. Highly orchestrated regulatory systems control cellular and systemic iron fluxes ensuring sufficient iron delivery to target proteins is maintained, while limiting its potentially deleterious effects in iron-mediated oxidative cell damage and ferroptosis. In this Review, we discuss how cells acquire, traffick and export iron and how stored iron is mobilized for iron-sulfur cluster and haem biogenesis. Furthermore, we describe how these cellular processes are fine-tuned by the combination of various sensory and regulatory systems, such as the iron-regulatory protein (IRP)-iron-responsive element (IRE) network, the nuclear receptor co-activator 4 (NCOA4)-mediated ferritinophagy pathway, the prolyl hydroxylase domain (PHD)-hypoxia-inducible factor (HIF) axis or the nuclear factor erythroid 2-related factor 2 (NRF2) regulatory hub. We further describe how these pathways interact with systemic iron homeostasis control through the hepcidin-ferroportin axis to ensure appropriate iron fluxes. This knowledge is key for the identification of novel therapeutic opportunities to prevent diseases of cellular and/or systemic iron mismanagement.
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Affiliation(s)
- Bruno Galy
- German Cancer Research Center (DKFZ), Division of Virus-associated Carcinogenesis (F170), Heidelberg, Germany
| | - Marcus Conrad
- Helmholtz Zentrum München, Institute of Metabolism and Cell Death, Neuherberg, Germany
| | - Martina Muckenthaler
- Department of Paediatric Hematology, Oncology and Immunology, University of Heidelberg, Heidelberg, Germany.
- Molecular Medicine Partnership Unit, University of Heidelberg, Heidelberg, Germany.
- German Centre for Cardiovascular Research (DZHK), Partner site Heidelberg/Mannheim, Heidelberg, Germany.
- Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany.
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5
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Bo Y, Mu L, Yang Z, Li W, Jin M. Research progress on ferroptosis in gliomas (Review). Oncol Lett 2024; 27:36. [PMID: 38108075 PMCID: PMC10722542 DOI: 10.3892/ol.2023.14169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 10/24/2023] [Indexed: 12/19/2023] Open
Abstract
Glioma is the most prevalent type of brain tumor characterized by a poor 5-year survival rate and a high mortality rate. Malignant gliomas are commonly treated by surgery, chemotherapy and radiotherapy. However, due to toxicity and resistance to chemoradiotherapy, these treatments can be ineffective. Anxiety and depression are highly prevalent in patients with glioma, adversely affecting disease prognosis and posing societal concerns. Ferroptosis is a type of non-apoptotic, iron-dependent cell death characterized by the accumulation of lethal reactive oxygen species produced by iron metabolism, and it serves a key role in numerous diseases. Regulation of iron phagocytosis may serve as a therapeutic strategy for the development of novel glioma treatments. The present review discusses the mechanisms underlying the occurrence and regulation of ferroptosis, its role in the genesis and evolution of gliomas, and its association with glioma-related anxiety and depression. By exploring potential targets for glioma treatment, the present review provides a theoretical basis for the development of novel therapeutic strategies against glioma.
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Affiliation(s)
- Yujie Bo
- Department of Neurosurgery, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China
| | - Luyan Mu
- Department of Neurosurgery, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China
| | - Zhao Yang
- Department of Neurosurgery, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China
| | - Wenhao Li
- Department of Neurosurgery, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China
| | - Ming Jin
- Department of Neurosurgery, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China
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6
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Jormakka M. Structural insights into ferroportin mediated iron transport. Biochem Soc Trans 2023; 51:BST20230594. [PMID: 38115725 DOI: 10.1042/bst20230594] [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: 10/25/2023] [Revised: 12/08/2023] [Accepted: 12/11/2023] [Indexed: 12/21/2023]
Abstract
Iron is a vital trace element for almost all organisms, and maintaining iron homeostasis is critical for human health. In mammals, the only known gatekeeper between intestinally absorbed iron and circulatory blood plasma is the membrane transporter ferroportin (Fpn). As such, dysfunction of Fpn or its regulation is a key driver of iron-related pathophysiology. This review focuses on discussing recent insights from high-resolution structural studies of the Fpn protein family. While these studies have unveiled crucial details of Fpn regulation and structural architecture, the associated functional studies have also at times provided conflicting data provoking more questions than answers. Here, we summarize key findings and illuminate important remaining questions and contradictions.
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Affiliation(s)
- Mika Jormakka
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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7
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Ginzburg Y, An X, Rivella S, Goldfarb A. Normal and dysregulated crosstalk between iron metabolism and erythropoiesis. eLife 2023; 12:e90189. [PMID: 37578340 PMCID: PMC10425177 DOI: 10.7554/elife.90189] [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: 06/16/2023] [Accepted: 08/06/2023] [Indexed: 08/15/2023] Open
Abstract
Erythroblasts possess unique characteristics as they undergo differentiation from hematopoietic stem cells. During terminal erythropoiesis, these cells incorporate large amounts of iron in order to generate hemoglobin and ultimately undergo enucleation to become mature red blood cells, ultimately delivering oxygen in the circulation. Thus, erythropoiesis is a finely tuned, multifaceted process requiring numerous properly timed physiological events to maintain efficient production of 2 million red blood cells per second in steady state. Iron is required for normal functioning in all human cells, the erythropoietic compartment consuming the majority in light of the high iron requirements for hemoglobin synthesis. Recent evidence regarding the crosstalk between erythropoiesis and iron metabolism sheds light on the regulation of iron availability by erythroblasts and the consequences of insufficient as well as excess iron on erythroid lineage proliferation and differentiation. In addition, significant progress has been made in our understanding of dysregulated iron metabolism in various congenital and acquired malignant and non-malignant diseases. Finally, we report several actual as well as theoretical opportunities for translating the recently acquired robust mechanistic understanding of iron metabolism regulation to improve management of patients with disordered erythropoiesis, such as anemia of chronic inflammation, β-thalassemia, polycythemia vera, and myelodysplastic syndromes.
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Affiliation(s)
- Yelena Ginzburg
- Division of Hematology and Medical Oncology, The Tisch Cancer Institute, Icahn School of Medicine at Mount SinaiNew YorkUnited States
| | - Xiuli An
- LFKRI, New York Blood CenterNew YorkUnited States
| | - Stefano Rivella
- Department of Pediatrics, Division of Hematology, The Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
- Cell and Molecular Biology affinity group (CAMB), University of PennsylvaniaPhiladelphiaUnited States
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics at the Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
- Penn Center for Musculoskeletal Disorders at the Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
- Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
- Institute for Regenerative Medicine at University of PennsylvaniaPhiladelphiaUnited States
- RNA Institute at University of PennsylvaniaPhiladelphiaUnited States
| | - Adam Goldfarb
- Department of Pathology, University of VirginiaCharlottesvilleUnited States
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8
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Liu D, Luo Y, Zheng Y, Ji R, Zhou Y. Effect of elevated serum ferritin on the risk of death in patients with decompensated cirrhosis: a meta-analysis. Eur J Gastroenterol Hepatol 2023; 35:795-802. [PMID: 37161969 DOI: 10.1097/meg.0000000000002566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
It is still debatable whether serum ferritin is a potential prognostic marker in patients with decompensated cirrhosis. In this meta-analysis, we hope to investigate the relationship between elevated serum ferritin and the risk of death in patients with decompensated cirrhosis. We systematically searched PubMed, Embase, Web of Science, Cochrane Library, CNKI, SinoMed, WAN FANG, and ClinicalTrials.gov without language restrictions from inception to 3 October 2022, and finally identified a total of eight eligible studies with 1829 patients. The pooled prevalence of elevated serum ferritin in decompensated cirrhosis was 40.6% [95% confidence interval (CI) 32.1-49.2%], and it was higher in males, patients with alcohol-associated liver disease, those with Child-Pugh grade C, those with hepatic encephalopathy, and nonsurvivors. Nonsurvivors had significantly higher serum ferritin levels than survivors [mean difference 247.90; 95% CI, 130.97-364.84]. With a pooled unadjusted hazard ratio of 2.38 (95% CI, 1.78-3.18), high serum ferritin was associated with an increased risk of death in patients with decompensated cirrhosis, with low heterogeneity among the included studies. In conclusion, high serum ferritin levels were associated with mortality in patients with decompensated cirrhosis. More prospective and homogeneous clinical studies are required to validate our findings.
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Affiliation(s)
- Dan Liu
- The First Clinical Medical College, Lanzhou University
- Department of Gastroenterology
- Key Laboratory for Gastrointestinal Diseases of Gansu Province, The First Hospital of Lanzhou University, Lanzhou, China
| | - Yuxin Luo
- The First Clinical Medical College, Lanzhou University
- Department of Gastroenterology
- Key Laboratory for Gastrointestinal Diseases of Gansu Province, The First Hospital of Lanzhou University, Lanzhou, China
| | - Ya Zheng
- Department of Gastroenterology
- Key Laboratory for Gastrointestinal Diseases of Gansu Province, The First Hospital of Lanzhou University, Lanzhou, China
| | - Rui Ji
- Department of Gastroenterology
- Key Laboratory for Gastrointestinal Diseases of Gansu Province, The First Hospital of Lanzhou University, Lanzhou, China
| | - Yongning Zhou
- Department of Gastroenterology
- Key Laboratory for Gastrointestinal Diseases of Gansu Province, The First Hospital of Lanzhou University, Lanzhou, China
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9
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Ohta K, Ito M, Chida T, Nakashima K, Sakai S, Kanegae Y, Kawasaki H, Aoshima T, Takabayashi S, Takahashi H, Kawata K, Shoji I, Sawasaki T, Suda T, Suzuki T. Role of hepcidin upregulation and proteolytic cleavage of ferroportin 1 in hepatitis C virus-induced iron accumulation. PLoS Pathog 2023; 19:e1011591. [PMID: 37585449 PMCID: PMC10461841 DOI: 10.1371/journal.ppat.1011591] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 08/28/2023] [Accepted: 07/31/2023] [Indexed: 08/18/2023] Open
Abstract
Hepatitis C virus (HCV) is a pathogen characterized not only by its persistent infection leading to the development of cirrhosis and hepatocellular carcinoma (HCC), but also by metabolic disorders such as lipid and iron dysregulation. Elevated iron load is commonly observed in the livers of patients with chronic hepatitis C, and hepatic iron overload is a highly profibrogenic and carcinogenic factor that increases the risk of HCC. However, the underlying mechanisms of elevated iron accumulation in HCV-infected livers remain to be fully elucidated. Here, we observed iron accumulation in cells and liver tissues under HCV infection and in mice expressing viral proteins from recombinant adenoviruses. We established two molecular mechanisms that contribute to increased iron load in cells caused by HCV infection. One is the transcriptional induction of hepcidin, the key hormone for modulating iron homeostasis. The transcription factor cAMP-responsive element-binding protein hepatocyte specific (CREBH), which was activated by HCV infection, not only directly recognizes the hepcidin promoter but also induces bone morphogenetic protein 6 (BMP6) expression, resulting in an activated BMP-SMAD pathway that enhances hepcidin promoter activity. The other is post-translational regulation of the iron-exporting membrane protein ferroportin 1 (FPN1), which is cleaved between residues Cys284 and Ala285 in the intracytoplasmic loop region of the central portion mediated by HCV NS3-4A serine protease. We propose that host transcriptional activation triggered by endoplasmic reticulum stress and FPN1 cleavage by viral protease work in concert to impair iron efflux, leading to iron accumulation in HCV-infected cells.
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Affiliation(s)
- Kazuyoshi Ohta
- 2nd Department of Internal Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
- Department of Microbiology and Immunology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Masahiko Ito
- Department of Microbiology and Immunology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Takeshi Chida
- Department of Regional Medical Care Support, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Kenji Nakashima
- Department of Microbiology and Immunology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Satoshi Sakai
- Department of Molecular Biology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Yumi Kanegae
- Core Research Facilities, Research Center for Medical Sciences, The Jikei University School of Medicine, Tokyo, Japan
| | - Hideya Kawasaki
- Institute for NanoSuit Research, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Takuya Aoshima
- Laboratory Animal Facilities & Services, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Shuji Takabayashi
- Laboratory Animal Facilities & Services, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Hirotaka Takahashi
- Division of Cell-Free Science, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan
| | - Kazuhito Kawata
- 2nd Department of Internal Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Ikuo Shoji
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Tatsuya Sawasaki
- Division of Cell-Free Science, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan
| | - Takafumi Suda
- 2nd Department of Internal Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Tetsuro Suzuki
- Department of Microbiology and Immunology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
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10
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Amadei M, Niro A, Fullone MR, Miele R, Polticelli F, Musci G, Bonaccorsi di Patti MC. Genetic Incorporation of Dansylalanine in Human Ferroportin to Probe the Alternating Access Mechanism of Iron Transport. Int J Mol Sci 2023; 24:11919. [PMID: 37569293 PMCID: PMC10418311 DOI: 10.3390/ijms241511919] [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: 06/23/2023] [Revised: 07/17/2023] [Accepted: 07/24/2023] [Indexed: 08/13/2023] Open
Abstract
Ferroportin (Fpn), a member of the major facilitator superfamily (MFS) of transporters, is the only known iron exporter found in mammals and plays a crucial role in regulating cellular and systemic iron levels. MFSs take on different conformational states during the transport cycle: inward open, occluded, and outward open. However, the precise molecular mechanism of iron translocation by Fpn remains unclear, with conflicting data proposing different models. In this work, amber codon suppression was employed to introduce dansylalanine (DA), an environment-sensitive fluorescent amino acid, into specific positions of human Fpn (V46, Y54, V161, Y331) predicted to undergo major conformational changes during metal translocation. The results obtained indicate that different mutants exhibit distinct fluorescence spectra depending on the position of the fluorophore within the Fpn structure, suggesting that different local environments can be probed. Cobalt titration experiments revealed fluorescence quenching and blue-shifts of λmax in Y54DA, V161DA, and Y331DA, while V46DA exhibited increased fluorescence and blue-shift of λmax. These observations suggest metal-induced conformational transitions, interpreted in terms of shifts from an outward-open to an occluded conformation. Our study highlights the potential of genetically incorporating DA into Fpn, enabling the investigation of conformational changes using fluorescence spectroscopy. This approach holds great promise for the study of the alternating access mechanism of Fpn and advancing our understanding of the molecular basis of iron transport.
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Affiliation(s)
- Matteo Amadei
- Department of Biochemical Sciences ‘A. Rossi Fanelli’, Sapienza University of Rome, 00185 Rome, Italy; (M.A.); (M.R.F.); (R.M.)
| | - Antonella Niro
- Department of Biosciences and Territory, University of Molise, 86090 Pesche, Italy; (A.N.); (G.M.)
| | - Maria Rosaria Fullone
- Department of Biochemical Sciences ‘A. Rossi Fanelli’, Sapienza University of Rome, 00185 Rome, Italy; (M.A.); (M.R.F.); (R.M.)
| | - Rossella Miele
- Department of Biochemical Sciences ‘A. Rossi Fanelli’, Sapienza University of Rome, 00185 Rome, Italy; (M.A.); (M.R.F.); (R.M.)
| | | | - Giovanni Musci
- Department of Biosciences and Territory, University of Molise, 86090 Pesche, Italy; (A.N.); (G.M.)
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11
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Ray S, Gaudet R. Structures and coordination chemistry of transporters involved in manganese and iron homeostasis. Biochem Soc Trans 2023; 51:897-923. [PMID: 37283482 PMCID: PMC10330786 DOI: 10.1042/bst20210699] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/23/2023] [Accepted: 05/25/2023] [Indexed: 06/08/2023]
Abstract
A repertoire of transporters plays a crucial role in maintaining homeostasis of biologically essential transition metals, manganese, and iron, thus ensuring cell viability. Elucidating the structure and function of many of these transporters has provided substantial understanding into how these proteins help maintain the optimal cellular concentrations of these metals. In particular, recent high-resolution structures of several transporters bound to different metals enable an examination of how the coordination chemistry of metal ion-protein complexes can help us understand metal selectivity and specificity. In this review, we first provide a comprehensive list of both specific and broad-based transporters that contribute to cellular homeostasis of manganese (Mn2+) and iron (Fe2+ and Fe3+) in bacteria, plants, fungi, and animals. Furthermore, we explore the metal-binding sites of the available high-resolution metal-bound transporter structures (Nramps, ABC transporters, P-type ATPase) and provide a detailed analysis of their coordination spheres (ligands, bond lengths, bond angles, and overall geometry and coordination number). Combining this information with the measured binding affinity of the transporters towards different metals sheds light into the molecular basis of substrate selectivity and transport. Moreover, comparison of the transporters with some metal scavenging and storage proteins, which bind metal with high affinity, reveal how the coordination geometry and affinity trends reflect the biological role of individual proteins involved in the homeostasis of these essential transition metals.
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Affiliation(s)
- Shamayeeta Ray
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, U.S.A
| | - Rachelle Gaudet
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, U.S.A
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12
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Azucenas CR, Ruwe TA, Bonamer JP, Qiao B, Ganz T, Jormakka M, Nemeth E, Mackenzie B. Comparative analysis of the functional properties of human and mouse ferroportin. Am J Physiol Cell Physiol 2023; 324:C1110-C1118. [PMID: 36939203 PMCID: PMC10191125 DOI: 10.1152/ajpcell.00063.2023] [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: 02/22/2023] [Revised: 03/16/2023] [Accepted: 03/16/2023] [Indexed: 03/21/2023]
Abstract
Ferroportin (Fpn)-expressed at the plasma membrane of macrophages, enterocytes, and hepatocytes-mediates the transfer of cellular iron into the blood plasma. Under the control of the iron-regulatory hormone hepcidin, Fpn serves a critical role in systemic iron homeostasis. Although we have previously characterized human Fpn, a great deal of research in iron homeostasis and disorders uses mouse models. By way of example, the flatiron mouse, a model of classical ferroportin disease, bears the mutation H32R in Fpn and is characterized by systemic iron deficiency and macrophage iron retention. The flatiron mouse also appears to exhibit a manganese phenotype, raising the possibility that mouse Fpn serves a role in manganese metabolism. At odds with this observation, we have found that human Fpn does not transport manganese, so we considered the possibility that a species difference could explain this discrepancy. We tested the hypothesis that mouse but not human Fpn can transport manganese and performed a comparative analysis of mouse and human Fpn. We examined the functional properties of human Fpn, mouse Fpn, and mutant mouse Fpn by using radiotracer assays in RNA-injected Xenopus oocytes. We found that neither mouse nor human Fpn transports manganese. Mouse and human Fpn share identical properties with respect to substrate profile, calcium dependence, optimal pH, and hepcidin sensitivity. We have also demonstrated that Fpn is not an ATPase pump. Our findings validate the use of mouse models of ferroportin function in iron homeostasis and disease.
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Affiliation(s)
- Corbin R Azucenas
- Department of Pharmacology & Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
- Medical Sciences Program, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
- Systems Biology & Physiology Program, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
| | - T Alex Ruwe
- Department of Pharmacology & Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
- Systems Biology & Physiology Program, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
| | - John P Bonamer
- Department of Pharmacology & Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
| | - Bo Qiao
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, United States
| | - Tomas Ganz
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, United States
- Department of Pathology, David Geffen School of Medicine at UCLA, Los Angeles, California, United States
| | - Mika Jormakka
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Elizabeta Nemeth
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, United States
| | - Bryan Mackenzie
- Department of Pharmacology & Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
- Medical Sciences Program, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
- Systems Biology & Physiology Program, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
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13
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Ginzburg YZ. Hepcidin and its multiple partners: Complex regulation of iron metabolism in health and disease. VITAMINS AND HORMONES 2023; 123:249-284. [PMID: 37717987 DOI: 10.1016/bs.vh.2023.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
The peptide hormone hepcidin is central to the regulation of iron metabolism, influencing the movement of iron into the circulation and determining total body iron stores. Its effect on a cellular level involves binding ferroportin, the main iron export protein, preventing iron egress and leading to iron sequestration within ferroportin-expressing cells. Hepcidin expression is enhanced by iron loading and inflammation and suppressed by erythropoietic stimulation. Aberrantly increased hepcidin leads to systemic iron deficiency and/or iron restricted erythropoiesis as occurs in anemia of chronic inflammation. Furthermore, insufficiently elevated hepcidin occurs in multiple diseases associated with iron overload such as hereditary hemochromatosis and iron loading anemias. Abnormal iron metabolism as a consequence of hepcidin dysregulation is an underlying factor resulting in pathophysiology of multiple diseases and several agents aimed at manipulating this pathway have been designed, with some already in clinical trials. In this chapter, we assess the complex regulation of hepcidin, delineate the many binding partners involved in its regulation, and present an update on the development of hepcidin agonists and antagonists in various clinical scenarios.
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Affiliation(s)
- Yelena Z Ginzburg
- Tisch Cancer Institute, Division of Hematology and Medical Oncology, Icahn School of Medicine at Mount Sinai, New York, NY, United Sates.
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14
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Lehmann EF, Liziczai M, Drożdżyk K, Altermatt P, Langini C, Manolova V, Sundstrom H, Dürrenberger F, Dutzler R, Manatschal C. Structures of ferroportin in complex with its specific inhibitor vamifeport. eLife 2023; 12:e83053. [PMID: 36943194 PMCID: PMC10030120 DOI: 10.7554/elife.83053] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 02/27/2023] [Indexed: 03/18/2023] Open
Abstract
A central regulatory mechanism of iron homeostasis in humans involves ferroportin (FPN), the sole cellular iron exporter, and the peptide hormone hepcidin, which inhibits Fe2+ transport and induces internalization and degradation of FPN. Dysregulation of the FPN/hepcidin axis leads to diverse pathological conditions, and consequently, pharmacological compounds that inhibit FPN-mediated iron transport are of high clinical interest. Here, we describe the cryo-electron microscopy structures of human FPN in complex with synthetic nanobodies and vamifeport (VIT-2763), the first clinical-stage oral FPN inhibitor. Vamifeport competes with hepcidin for FPN binding and is currently in clinical development for β-thalassemia and sickle cell disease. The structures display two distinct conformations of FPN, representing outward-facing and occluded states of the transporter. The vamifeport site is located in the center of the protein, where the overlap with hepcidin interactions underlies the competitive relationship between the two molecules. The introduction of point mutations in the binding pocket of vamifeport reduces its affinity to FPN, emphasizing the relevance of the structural data. Together, our study reveals conformational rearrangements of FPN that are of potential relevance for transport, and it provides initial insight into the pharmacological targeting of this unique iron efflux transporter.
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Affiliation(s)
| | - Márton Liziczai
- Department of Biochemistry, University of ZurichZürichSwitzerland
| | | | | | - Cassiano Langini
- Department of Biochemistry, University of ZurichZürichSwitzerland
| | | | | | | | - Raimund Dutzler
- Department of Biochemistry, University of ZurichZürichSwitzerland
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15
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Abstract
Hepcidin, the iron-regulatory hormone, determines plasma iron concentrations and total body iron content. Hepcidin, secreted by hepatocytes, functions by controlling the activity of the cellular iron exporter ferroportin, which delivers iron to plasma from intestinal iron absorption and from iron stores. Hepcidin concentration in plasma is increased by iron loading and inflammation and is suppressed by erythropoietic stimulation and during pregnancy. Hepcidin deficiency causes iron overload in hemochromatosis and anemias with ineffective erythropoiesis. Hepcidin excess causes iron-restrictive anemias including anemia of inflammation. The development of hepcidin diagnostics and therapeutic agonists and antagonists should improve the treatment of iron disorders.
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Affiliation(s)
- Elizabeta Nemeth
- Center for Iron Disorders, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, USA;
| | - Tomas Ganz
- Center for Iron Disorders, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, USA;
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16
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Roterman I, Stapor K, Konieczny L. The Contribution of Hydrophobic Interactions to Conformational Changes of Inward/Outward Transmembrane Transport Proteins. MEMBRANES 2022; 12:membranes12121212. [PMID: 36557119 PMCID: PMC9784565 DOI: 10.3390/membranes12121212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/27/2022] [Accepted: 11/27/2022] [Indexed: 05/21/2023]
Abstract
Proteins transporting ions or other molecules across the membrane, whose proper concentration is required to maintain homeostasis, perform very sophisticated biological functions. The symport and antiport active transport can be performed only by the structures specially prepared for this purpose. In the present work, such structures in both In and Out conformations have been analyzed with respect to the hydrophobicity distribution using the FOD-M model. This allowed for identifying the role of individual protein chain fragments in the stabilization of the specific cell membrane environment as well as the contribution of hydrophobic interactions to the conformational changes between In/Out conformations.
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Affiliation(s)
- Irena Roterman
- Department of Bioinformatics and Telemedicine, Jagiellonian University—Medical College Medyczna 7, 30-688 Kraków, Poland
- Correspondence:
| | - Katarzyna Stapor
- Department of Applied Informatics, Faculty of Automatic, Electronics and Computer Science, Silesian University of Technology, Akademicka 16, 44-100 Gliwice, Poland
| | - Leszek Konieczny
- Chair of Medical Biochemistry—Jagiellonian University—Medical College, Kopernika 7, 31-034 Kraków, Poland
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17
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Kawabata T. Iron-Induced Oxidative Stress in Human Diseases. Cells 2022; 11:cells11142152. [PMID: 35883594 PMCID: PMC9324531 DOI: 10.3390/cells11142152] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/30/2022] [Accepted: 07/04/2022] [Indexed: 11/16/2022] Open
Abstract
Iron is responsible for the regulation of several cell functions. However, iron ions are catalytic and dangerous for cells, so the cells sequester such redox-active irons in the transport and storage proteins. In systemic iron overload and local pathological conditions, redox-active iron increases in the human body and induces oxidative stress through the formation of reactive oxygen species. Non-transferrin bound iron is a candidate for the redox-active iron in extracellular space. Cells take iron by the uptake machinery such as transferrin receptor and divalent metal transporter 1. These irons are delivered to places where they are needed by poly(rC)-binding proteins 1/2 and excess irons are stored in ferritin or released out of the cell by ferroportin 1. We can imagine transit iron pool in the cell from iron import to the export. Since the iron in the transit pool is another candidate for the redox-active iron, the size of the pool may be kept minimally. When a large amount of iron enters cells and overflows the capacity of iron binding proteins, the iron behaves as a redox-active iron in the cell. This review focuses on redox-active iron in extracellular and intracellular spaces through a biophysical and chemical point of view.
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Affiliation(s)
- Teruyuki Kawabata
- Department of Applied Physics, Postgraduate School of Science, Okayama University of Science, Okayama 700-0005, Japan
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18
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Utilization of AlphaFold2 to Predict MFS Protein Conformations after Selective Mutation. Int J Mol Sci 2022; 23:ijms23137235. [PMID: 35806248 PMCID: PMC9266783 DOI: 10.3390/ijms23137235] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/23/2022] [Accepted: 06/26/2022] [Indexed: 02/05/2023] Open
Abstract
The major facilitator superfamily (MFS) is the largest secondary transporter family and is responsible for transporting a broad range of substrates across the biomembrane. These proteins are involved in a series of conformational changes during substrate transport. To decipher the transport mechanism, it is necessary to obtain structures of these different conformations. At present, great progress has been made in predicting protein structure based on coevolutionary information. In this study, AlphaFold2 was used to predict different conformational structures for 69 MFS transporters of E. coli after the selective mutation of residues at the interface between the N- and C-terminal domains. The predicted structures for these mutants had small RMSD values when compared to structures obtained using X-ray crystallography, which indicates that AlphaFold2 predicts the structure of MSF transporters with high accuracy. In addition, different conformations of other transporter family proteins have been successfully predicted based on mutation methods. This study provides a structural basis to study the transporting mechanism of the MFS transporters and a method to probe dynamic conformation changes of transporter family proteins when performing their function.
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19
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Prabu R, Mohanty A, Balakrishnan SS, Jayalakshmi G, Sundar K. Molecular docking and simulation of IcaC protein as O-succinyltransferase function in staphylococcus epidermidis biofilm formation. Curr Res Struct Biol 2022; 4:78-86. [PMID: 35399651 PMCID: PMC8987812 DOI: 10.1016/j.crstbi.2022.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/19/2022] [Accepted: 03/13/2022] [Indexed: 12/04/2022] Open
Abstract
Intercellular adhesion (IcaADBC) operon is necessary for PNAG (Polyβ-1,6-N-acetyl-D-glucosamine) biosynthesis of biofilm formation in Staphylococcus epidermidis. IcaC protein has a wide range of functions in terms of growth phase variation, migration, transposon insertion, PNAG modification, biofilm formation. Unusual TTTA signature motifs were identified from nucleotide sequence. Asparagine-linked glycosylation consensus motifs were identified at position 169 and 240. S. epidermidis was a close evolutionary association with S. haemolyticus and other Staphylococcus spp. Due to the non-availability of crystal structure, protein threading procedure was selected for constructing a full length IcaC three-dimensional structure. QMEANBrane structure quality assessment with model scores −100000 range within predicted integral membrane structure. IcaC motif constitutes 18 transmembrane helix, 37 helix-helix interaction, 8 beta turn, 2 gamma turn. Binding free energy was calculated with their succinate ligand docking form hydrogen bond with critical amino acids showed ΔG score −2.574 kJ/mol using Schrödinger. Serine (Ser96), Glutamic acid (Glu99), Tryptophan (Trp191) were active site amino acids form the catalytic core required for O-succinyltransferase function. Molecular dynamics simulation (MDS) was performed to evaluate the stability of IcaC protein and IcaC-Succinate binding complexes with the active site amino acids throughout trajectories captured with time scale 100 ns simulation period using GROMACS 4.5. Structural characterization of Intercellular adhesion (IcaC) protein from Staphylococcus epidermidis. Understanding of nucleotide, protein signature sequence, secondary structure motifs and phylogenetic association among Staphylococcus sp. homologs. IcaC-Succinate docking and molecular dynamics simulation for determined structural stability of protein.
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20
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Wang L, Zhang J, Wang D, Song C. Membrane contact probability: An essential and predictive character for the structural and functional studies of membrane proteins. PLoS Comput Biol 2022; 18:e1009972. [PMID: 35353812 PMCID: PMC9000120 DOI: 10.1371/journal.pcbi.1009972] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/11/2022] [Accepted: 02/25/2022] [Indexed: 11/20/2022] Open
Abstract
One of the unique traits of membrane proteins is that a significant fraction of their hydrophobic amino acids is exposed to the hydrophobic core of lipid bilayers rather than being embedded in the protein interior, which is often not explicitly considered in the protein structure and function predictions. Here, we propose a characteristic and predictive quantity, the membrane contact probability (MCP), to describe the likelihood of the amino acids of a given sequence being in direct contact with the acyl chains of lipid molecules. We show that MCP is complementary to solvent accessibility in characterizing the outer surface of membrane proteins, and it can be predicted for any given sequence with a machine learning-based method by utilizing a training dataset extracted from MemProtMD, a database generated from molecular dynamics simulations for the membrane proteins with a known structure. As the first of many potential applications, we demonstrate that MCP can be used to systematically improve the prediction precision of the protein contact maps and structures. The distribution of residues on protein surfaces is largely determined by the surrounding environment. For soluble proteins, most of the residues on the outer surface are hydrophilic, and people use the quantity “solvent accessibility” to describe and predict these surface residues. In contrast, for membrane proteins that are embedded in a lipid bilayer, many of their surface residues are hydrophobic and membrane-contacting, but there is yet a widely-accepted quantity for the description or prediction of this characteristic property. Here, we propose a new quantity termed “membrane contact probability (MCP)”, which can be used to describe and predict the membrane-contacting surface residues of proteins. We also propose a machine learning-based method to predict MCP from protein sequences, utilizing the dataset generated by physics-based computer simulations. We demonstrate that a quantity such as MCP is helpful for protein structure prediction, and we believe that it will find broad applications in the structure and function studies of membrane proteins.
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Affiliation(s)
- Lei Wang
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary studies, Peking University, Beijing, China
| | - Jiangguo Zhang
- School of Life Sciences, Peking University, Beijing, China
| | - Dali Wang
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary studies, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Chen Song
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary studies, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- * E-mail:
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21
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Ehsan M, Wang H, Cecchetti C, Mortensen JS, Du Y, Hariharan P, Nygaard A, Lee HJ, Ghani L, Guan L, Loland CJ, Byrne B, Kobilka BK, Chae PS. Maltose-bis(hydroxymethyl)phenol (MBPs) and Maltose-tris(hydroxymethyl)phenol (MTPs) Amphiphiles for Membrane Protein Stability. ACS Chem Biol 2021; 16:1779-1790. [PMID: 34445864 DOI: 10.1021/acschembio.1c00578] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Membrane protein structures provide a fundamental understanding of their molecular actions and are of importance for drug development. Detergents are widely used to solubilize, stabilize, and crystallize membrane proteins, but membrane proteins solubilized in conventional detergents are prone to denaturation and aggregation. Thus, developing novel detergents with enhanced efficacy for protein stabilization remains important. We report herein the design and synthesis of a class of phenol-derived maltoside detergents. Using two different linkers, we prepared two sets of new detergents, designated maltose-bis(hydroxymethyl)phenol (MBPs) and maltose-tris(hydroxymethyl)phenol (MTPs). The evaluation of these detergents with three transporters and two G-protein coupled receptors allowed us to identify a couple of new detergents (MBP-C9 and MTP-C12) that consistently conferred enhanced stability to all tested proteins compared to a gold standard detergent (DDM). Furthermore, the data analysis based on the detergent structures provides key detergent features responsible for membrane protein stabilization that together will facilitate the future design of novel detergents.
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Affiliation(s)
- Muhammad Ehsan
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 155-88, South Korea
| | - Haoqing Wang
- Department of Molecular and Cellular Physiology, Stanford University, California 94305, United States
| | - Cristina Cecchetti
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Jonas S. Mortensen
- Department of Neuroscience, University of Copenhagen, DK-2200, Copenhagen, Denmark
| | - Yang Du
- Department of Molecular and Cellular Physiology, Stanford University, California 94305, United States
| | - Parameswaran Hariharan
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States
| | - Andreas Nygaard
- Department of Neuroscience, University of Copenhagen, DK-2200, Copenhagen, Denmark
| | - Ho Jin Lee
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 155-88, South Korea
| | - Lubna Ghani
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 155-88, South Korea
| | - Lan Guan
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States
| | - Claus J. Loland
- Department of Neuroscience, University of Copenhagen, DK-2200, Copenhagen, Denmark
| | - Bernadette Byrne
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Brian K. Kobilka
- Department of Molecular and Cellular Physiology, Stanford University, California 94305, United States
| | - Pil Seok Chae
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 155-88, South Korea
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22
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Zhou F, Yang Y, Chemuru S, Cui W, Liu S, Gross M, Li W. Footprinting Mass Spectrometry of Membrane Proteins: Ferroportin Reconstituted in Saposin A Picodiscs. Anal Chem 2021; 93:11370-11378. [PMID: 34383472 DOI: 10.1021/acs.analchem.1c02325] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Membrane proteins participate in a broad range of cellular processes and represent more than 60% of drug targets. One approach to their structural analyses is mass spectrometry (MS)-based footprinting including hydrogen/deuterium exchange (HDX), fast photochemical oxidation of proteins (FPOP), and residue-specific chemical modification. Studying membrane proteins usually requires their isolation from the native lipid environment, after which they often become unstable. To overcome this problem, we are pursuing a novel methodology of incorporating membrane proteins into saposin A picodiscs for MS footprinting. We apply different footprinting approaches to a model membrane protein, mouse ferroportin, in picodiscs and achieve high coverage that enables the analysis of the ferroportin structure. FPOP footprinting shows extensive labeling of the extramembrane regions of ferroportin and protection at its transmembrane regions, suggesting that the membrane folding of ferroportin is maintained throughout the labeling process. In contrast, an amphipathic reagent, N-ethylmaleimide (NEM), efficiently labels cysteine residues in both extramembrane and transmembrane regions, thereby affording complementary footprinting coverage. Finally, optimization of sample treatment gives a peptic-map of ferroportin in picodiscs with 92% sequence coverage, setting the stage for HDX. These results, taken together, show that picodiscs are a new platform broadly applicable to mass spectrometry studies of membrane proteins.
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Affiliation(s)
- Fengbo Zhou
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Yihu Yang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Saketh Chemuru
- Department of Chemistry, Washington University, St. Louis, Missouri 63110, United States
| | - Weidong Cui
- Department of Chemistry, Washington University, St. Louis, Missouri 63110, United States
| | - Shixuan Liu
- Department of Chemistry, Washington University, St. Louis, Missouri 63110, United States
| | - Michael Gross
- Department of Chemistry, Washington University, St. Louis, Missouri 63110, United States
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, United States
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23
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Cysteine Mutants of the Major Facilitator Superfamily-Type Transporter CcoA Provide Insight into Copper Import. mBio 2021; 12:e0156721. [PMID: 34281385 PMCID: PMC8406296 DOI: 10.1128/mbio.01567-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
CcoA belongs to the widely distributed bacterial copper (Cu) importer subfamily CalT (CcoA-like Transporters) of the Major Facilitator Superfamily (MFS) and provides cytoplasmic Cu needed for cbb3-type cytochrome c oxidase (cbb3-Cox) biogenesis. Earlier studies have supported a 12-transmembrane helix (TMH) topology of CcoA with the well-conserved Met233xxxMet237 and His261xxxMet265 motifs in its TMH7 and TMH8, respectively. Of these residues, Met233 and His261 are essential for Cu uptake and cbb3-Cox production, whereas Met237 and Met265 contribute partly to these processes. CcoA also contains five Cys residues of unknown role and, remarkably, its structural models predict that three of these are exposed to the highly oxidizing periplasm. Here, we first demonstrate that elimination of both Met237 and Met265 completely abolishes Cu uptake and cbb3-Cox production, indicating that CcoA requires at least one of these two Met residues for activity. Second, using scanning mutagenesis to probe plausible metal-interacting Met, His, and Cys residues of CcoA, we found that the periplasm-exposed Cys49 located at the end of TMH2, the Cys247 on a surface loop between TMH7 and THM8, and the C367 located at the end of TMH11 are important for CcoA function. Analyses of the single and double Cys mutants revealed the occurrence of a disulfide bond in CcoA in vivo, possibly related to conformational changes it undergoes during Cu import as MFS-type transporter. Our overall findings suggest a model linking Cu import for cbb3-Cox biogenesis with a thiol:disulfide oxidoreduction step, advancing our understanding of the mechanisms of CcoA function.
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24
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Kim LJ, Tsuyuki KM, Hu F, Park EY, Zhang J, Iraheta JG, Chia JC, Huang R, Tucker AE, Clyne M, Castellano C, Kim A, Chung DD, DaVeiga CT, Parsons EM, Vatamaniuk OK, Jeong J. Ferroportin 3 is a dual-targeted mitochondrial/chloroplast iron exporter necessary for iron homeostasis in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:215-236. [PMID: 33884692 PMCID: PMC8316378 DOI: 10.1111/tpj.15286] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 04/10/2021] [Indexed: 05/26/2023]
Abstract
Mitochondria and chloroplasts are organelles with high iron demand that are particularly susceptible to iron-induced oxidative stress. Despite the necessity of strict iron regulation in these organelles, much remains unknown about mitochondrial and chloroplast iron transport in plants. Here, we propose that Arabidopsis ferroportin 3 (FPN3) is an iron exporter that is dual-targeted to mitochondria and chloroplasts. FPN3 is expressed in shoots, regardless of iron conditions, but its transcripts accumulate under iron deficiency in roots. fpn3 mutants cannot grow as well as the wild type under iron-deficient conditions and their shoot iron levels are lower compared with the wild type. Analyses of iron homeostasis gene expression in fpn3 mutants and inductively coupled plasma mass spectrometry (ICP-MS) measurements show that iron levels in the mitochondria and chloroplasts are increased relative to the wild type, consistent with the proposed role of FPN3 as a mitochondrial/plastid iron exporter. In iron-deficient fpn3 mutants, abnormal mitochondrial ultrastructure was observed, whereas chloroplast ultrastructure was not affected, implying that FPN3 plays a critical role in the mitochondria. Overall, our study suggests that FPN3 is essential for optimal iron homeostasis.
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Affiliation(s)
- Leah J. Kim
- Department of Biology, Amherst College, Amherst, Massachusetts 01002
| | | | - Fengling Hu
- Department of Biology, Amherst College, Amherst, Massachusetts 01002
| | - Emily Y. Park
- Department of Biology, Amherst College, Amherst, Massachusetts 01002
| | - Jingwen Zhang
- Department of Biology, Amherst College, Amherst, Massachusetts 01002
| | | | - Ju-Chen Chia
- Soil and Crop Sciences Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853
| | - Rong Huang
- Cornell High Energy Synchrotron Source, Ithaca, New York 14853
| | - Avery E. Tucker
- Department of Biology, Amherst College, Amherst, Massachusetts 01002
| | - Madeline Clyne
- Department of Biology, Amherst College, Amherst, Massachusetts 01002
| | - Claire Castellano
- Department of Biology, Amherst College, Amherst, Massachusetts 01002
| | - Angie Kim
- Department of Biology, Amherst College, Amherst, Massachusetts 01002
| | - Daniel D. Chung
- Department of Biology, Amherst College, Amherst, Massachusetts 01002
| | | | | | - Olena K. Vatamaniuk
- Soil and Crop Sciences Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853
| | - Jeeyon Jeong
- Department of Biology, Amherst College, Amherst, Massachusetts 01002
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Hepcidin-Ferroportin Interaction Controls Systemic Iron Homeostasis. Int J Mol Sci 2021; 22:ijms22126493. [PMID: 34204327 PMCID: PMC8235187 DOI: 10.3390/ijms22126493] [Citation(s) in RCA: 200] [Impact Index Per Article: 66.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/14/2021] [Accepted: 06/14/2021] [Indexed: 12/13/2022] Open
Abstract
Despite its abundance in the environment, iron is poorly bioavailable and subject to strict conservation and internal recycling by most organisms. In vertebrates, the stability of iron concentration in plasma and extracellular fluid, and the total body iron content are maintained by the interaction of the iron-regulatory peptide hormone hepcidin with its receptor and cellular iron exporter ferroportin (SLC40a1). Ferroportin exports iron from duodenal enterocytes that absorb dietary iron, from iron-recycling macrophages in the spleen and the liver, and from iron-storing hepatocytes. Hepcidin blocks iron export through ferroportin, causing hypoferremia. During iron deficiency or after hemorrhage, hepcidin decreases to allow iron delivery to plasma through ferroportin, thus promoting compensatory erythropoiesis. As a host defense mediator, hepcidin increases in response to infection and inflammation, blocking iron delivery through ferroportin to blood plasma, thus limiting iron availability to invading microbes. Genetic diseases that decrease hepcidin synthesis or disrupt hepcidin binding to ferroportin cause the iron overload disorder hereditary hemochromatosis. The opposite phenotype, iron restriction or iron deficiency, can result from genetic or inflammatory overproduction of hepcidin.
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Insights into the Role of the Discontinuous TM7 Helix of Human Ferroportin through the Prism of the Asp325 Residue. Int J Mol Sci 2021; 22:ijms22126412. [PMID: 34203920 PMCID: PMC8232785 DOI: 10.3390/ijms22126412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/09/2021] [Accepted: 06/11/2021] [Indexed: 11/16/2022] Open
Abstract
The negatively charged Asp325 residue has proved to be essential for iron export by human (HsFPN1) and primate Philippine tarsier (TsFpn) ferroportin, but its exact role during the iron transport cycle is still to be elucidated. It has been posited as being functionally equivalent to the metal ion-coordinating residue His261 in the C-lobe of the bacterial homolog BbFpn, but the two residues arise in different sequence motifs of the discontinuous TM7 transmembrane helix. Furthermore, BbFpn is not subject to extracellular regulation, contrary to its mammalian orthologues which are downregulated by hepcidin. To get further insight into the molecular mechanisms related to iron export in mammals in which Asp325 is involved, we investigated the behavior of the Asp325Ala, Asp325His, and Asp325Asn mutants in transiently transfected HEK293T cells, and performed a comparative structural analysis. Our biochemical studies clearly distinguished between the Asp325Ala and Asp325His mutants, which result in a dramatic decrease in plasma membrane expression of FPN1, and the Asp325Asn mutant, which alters iron egress without affecting protein localization. Analysis of the 3D structures of HsFPN1 and TsFpn in the outward-facing (OF) state indicated that Asp325 does not interact directly with metal ions but is involved in the modulation of Cys326 metal-binding capacity. Moreover, models of the architecture of mammalian proteins in the inward-facing (IF) state suggested that Asp325 may form an inter-lobe salt-bridge with Arg40 (TM1) when not interacting with Cys326. These findings allow to suggest that Asp325 may be important for fine-tuning iron recognition in the C-lobe, as well as for local structural changes during the IF-to-OF transition at the extracellular gate level. Inability to form a salt-bridge between TM1 and TM7b during iron translocation could lead to protein instability, as shown by the Asp325Ala and Asp325His mutants.
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Colucci S, Marques O, Altamura S. 20 years of Hepcidin: How far we have come. Semin Hematol 2021; 58:132-144. [PMID: 34389105 DOI: 10.1053/j.seminhematol.2021.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/12/2021] [Accepted: 05/31/2021] [Indexed: 12/20/2022]
Abstract
Twenty years ago the discovery of hepcidin deeply changed our understanding of the regulation of systemic iron homeostasis. It is now clear that hepcidin orchestrates systemic iron levels by controlling the amount of iron exported into the bloodstream through ferroportin. Hepcidin expression is increased in situations where systemic iron levels should be reduced, such as in iron overload and infection. Conversely, hepcidin is repressed during iron deficiency, hypoxia or expanded erythropoiesis, to increase systemic iron availability and sustain erythropoiesis. In this review, we will focus on molecular mechanisms of hepcidin regulation and on the pathological consequences of their disruption.
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Affiliation(s)
- Silvia Colucci
- Department of Pediatric Hematology, Oncology and Immunology - University of Heidelberg, Heidelberg, Germany.; Molecular Medicine Partnership Unit, EMBL and University of Heidelberg, Heidelberg, Germany
| | - Oriana Marques
- Department of Pediatric Hematology, Oncology and Immunology - University of Heidelberg, Heidelberg, Germany.; Molecular Medicine Partnership Unit, EMBL and University of Heidelberg, Heidelberg, Germany
| | - Sandro Altamura
- Department of Pediatric Hematology, Oncology and Immunology - University of Heidelberg, Heidelberg, Germany.; Molecular Medicine Partnership Unit, EMBL and University of Heidelberg, Heidelberg, Germany..
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28
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Human ferroportin mediates proton-coupled active transport of iron. Blood Adv 2021; 4:4758-4768. [PMID: 33007076 DOI: 10.1182/bloodadvances.2020001864] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 08/27/2020] [Indexed: 12/14/2022] Open
Abstract
As the sole iron exporter in humans, ferroportin controls systemic iron homeostasis through exporting iron into the blood plasma. The molecular mechanism of how ferroportin exports iron under various physiological settings remains unclear. Here we found that purified ferroportin incorporated into liposomes preferentially transports Fe2+ and exhibits lower affinities of transporting other divalent metal ions. The iron transport by ferroportin is facilitated by downhill proton gradients at the same direction. Human ferroportin is also capable of transporting protons, and this activity is tightly coupled to the iron transport. Remarkably, ferroportin can conduct active transport uphill against the iron gradient, with favorable charge potential providing the driving force. Targeted mutagenesis suggests that the iron translocation site is located at the pore region of human ferroportin. Together, our studies enhance the mechanistic understanding by which human ferroportin transports iron and suggest that a combination of electrochemical gradients regulates iron export.
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29
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Drew D, North RA, Nagarathinam K, Tanabe M. Structures and General Transport Mechanisms by the Major Facilitator Superfamily (MFS). Chem Rev 2021; 121:5289-5335. [PMID: 33886296 PMCID: PMC8154325 DOI: 10.1021/acs.chemrev.0c00983] [Citation(s) in RCA: 168] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Indexed: 12/12/2022]
Abstract
The major facilitator superfamily (MFS) is the largest known superfamily of secondary active transporters. MFS transporters are responsible for transporting a broad spectrum of substrates, either down their concentration gradient or uphill using the energy stored in the electrochemical gradients. Over the last 10 years, more than a hundred different MFS transporter structures covering close to 40 members have provided an atomic framework for piecing together the molecular basis of their transport cycles. Here, we summarize the remarkable promiscuity of MFS members in terms of substrate recognition and proton coupling as well as the intricate gating mechanisms undergone in achieving substrate translocation. We outline studies that show how residues far from the substrate binding site can be just as important for fine-tuning substrate recognition and specificity as those residues directly coordinating the substrate, and how a number of MFS transporters have evolved to form unique complexes with chaperone and signaling functions. Through a deeper mechanistic description of glucose (GLUT) transporters and multidrug resistance (MDR) antiporters, we outline novel refinements to the rocker-switch alternating-access model, such as a latch mechanism for proton-coupled monosaccharide transport. We emphasize that a full understanding of transport requires an elucidation of MFS transporter dynamics, energy landscapes, and the determination of how rate transitions are modulated by lipids.
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Affiliation(s)
- David Drew
- Department
of Biochemistry and Biophysics, Stockholm
University, SE 106 91 Stockholm, Sweden
| | - Rachel A. North
- Department
of Biochemistry and Biophysics, Stockholm
University, SE 106 91 Stockholm, Sweden
| | - Kumar Nagarathinam
- Center
of Structural and Cell Biology in Medicine, Institute of Biochemistry, University of Lübeck, D-23538, Lübeck, Germany
| | - Mikio Tanabe
- Structural
Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Oho 1-1, Tsukuba, Ibaraki 305-0801, Japan
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30
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Evidence for dimerization of ferroportin in a human hepatic cell line using proximity ligation assays. Biosci Rep 2021; 40:222672. [PMID: 32301493 PMCID: PMC7201565 DOI: 10.1042/bsr20191499] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 04/08/2020] [Accepted: 04/16/2020] [Indexed: 12/30/2022] Open
Abstract
Mutations in the only known iron exporter ferroportin (FPN) in humans are associated with the autosomal dominantly inherited iron overload disorder ferroportin disease or type IV hereditary hemochromatosis (HH). While our knowledge of the central role of FPN in iron homeostasis has grown in the last 20 years, there exist some questions surrounding the structure and membrane topology of FPN with conflicting data on whether this receptor acts as a monomer or a multimer. To investigate and determine if FPN dimerization occurs in cells, we used novel tools including a variety of different FPN constructs expressing different tagged versions of the protein, a novel antibody that only detects cell surface FPN and proximity ligation assays. The results of the present study suggest that both the carboxy- and amino-termini of the FPN protein are intracellular. We also show that exogenously transfected FPN forms dimers; these dimers can be formed between the wild-type and mutant FPN proteins. This is the first study to examine the intracellular dimerization of FPN protein. Using proximity ligation assays, we show intracellular localization of FPN dimers and the interaction between FPN and hepcidin proteins as well. These results have important implications in the field of iron metabolism and add to our knowledge about FPN membrane topology and physiology of iron transport. This will be of importance in understanding the clinical implications of FPN mutations and of interest to future research aimed at targeting FPN expression to modulate iron homeostasis.
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31
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Liu Q, Wu J, Zhang X, Wu X, Zhao Y, Ren J. Iron homeostasis and disorders revisited in the sepsis. Free Radic Biol Med 2021; 165:1-13. [PMID: 33486088 DOI: 10.1016/j.freeradbiomed.2021.01.025] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/31/2020] [Accepted: 01/11/2021] [Indexed: 12/26/2022]
Abstract
Sepsis is a life-threatening condition caused by a dysregulated host-response to inflammation, although it currently lacks a fully elucidated pathobiology. Iron is a crucial trace element that is essential for fundamental processes in both humans and bacteria. During sepsis, iron metabolism is altered, including increased iron transport and uptake into cells and decreased iron export. The intracellular sequestration of iron limits its availability to circulating pathogens, which serves as a conservative strategy against the pathogens. Although iron retention has been showed to have protective protect effects, an increase in labile iron may cause oxidative injury and cell death (e.g., pyroptosis, ferroptosis) as the condition progresses. Moreover, iron disorders are substantial and correlate with the severity of sepsis. This also suggests that iron may be useful as a diagnostic marker for evaluating the severity and predicting the outcome of the disease. Further knowledge about these disorders could help in evaluating how drugs targeting iron homeostasis can be optimally applied to improve the treatment of patients with sepsis. Here, we present a comprehensive review of recent advances in the understanding of iron metabolism, focusing on the regulatory mechanisms and iron-mediated injury in sepsis.
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Affiliation(s)
- Qinjie Liu
- Research Institute of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, PR China.
| | - Jie Wu
- Department of General Surgery, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, 210002, PR China.
| | - Xufei Zhang
- Research Institute of General Surgery, Jinling Hospital, Nanjing Medical University, Nanjing, 210002, PR China.
| | - Xiuwen Wu
- Research Institute of General Surgery, Jinling Hospital, Nanjing, 210002, PR China.
| | - Yun Zhao
- Department of General Surgery, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, 210002, PR China.
| | - Jianan Ren
- Research Institute of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, PR China; Department of General Surgery, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, 210002, PR China; Research Institute of General Surgery, Jinling Hospital, Nanjing Medical University, Nanjing, 210002, PR China.
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32
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Das M, Mahler F, Hariharan P, Wang H, Du Y, Mortensen JS, Patallo EP, Ghani L, Glück D, Lee HJ, Byrne B, Loland CJ, Guan L, Kobilka BK, Keller S, Chae PS. Diastereomeric Cyclopentane-Based Maltosides (CPMs) as Tools for Membrane Protein Study. J Am Chem Soc 2020; 142:21382-21392. [PMID: 33315387 PMCID: PMC8015409 DOI: 10.1021/jacs.0c09629] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Amphiphilic agents, called detergents, are invaluable tools for studying membrane proteins. However, membrane proteins encapsulated by conventional head-to-tail detergents tend to denature or aggregate, necessitating the development of structurally distinct molecules with improved efficacy. Here, a novel class of diastereomeric detergents with a cyclopentane core unit, designated cyclopentane-based maltosides (CPMs), were prepared and evaluated for their ability to solubilize and stabilize several model membrane proteins. A couple of CPMs displayed enhanced behavior compared with the benchmark conventional detergent, n-dodecyl-β-d-maltoside (DDM), for all the tested membrane proteins including two G-protein-coupled receptors (GPCRs). Furthermore, CPM-C12 was notable for its ability to confer enhanced membrane protein stability compared with the previously developed conformationally rigid NBMs [J. Am. Chem. Soc. 2017, 139, 3072] and LMNG. The effect of the individual CPMs on protein stability varied depending on both the detergent configuration (cis/trans) and alkyl chain length, allowing us draw conclusions on the detergent structure-property-efficacy relationship. Thus, this study not only provides novel detergent tools useful for membrane protein research but also reports on structural features of the detergents critical for detergent efficacy in stabilizing membrane proteins.
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Affiliation(s)
- Manabendra Das
- Department of Bionanotechnology, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 155-88, Korea
- Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
| | - Florian Mahler
- Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
| | - Parameswaran Hariharan
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States
| | - Haoqing Wang
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, United States
| | - Yang Du
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, United States
| | - Jonas S Mortensen
- Department of Neuroscience, University of Copenhagen, Copenhagen DK-2200, Denmark
| | - Eugenio Pérez Patallo
- Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
| | - Lubna Ghani
- Department of Bionanotechnology, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 155-88, Korea
| | - David Glück
- Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
| | - Ho Jin Lee
- Department of Bionanotechnology, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 155-88, Korea
| | - Bernadette Byrne
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Claus J Loland
- Department of Neuroscience, University of Copenhagen, Copenhagen DK-2200, Denmark
| | - Lan Guan
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States
| | - Brian K Kobilka
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, United States
| | - Sandro Keller
- Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
- Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Humboldtstr. 50/III, 8010 Graz, Austria
- Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Pil Seok Chae
- Department of Bionanotechnology, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 155-88, Korea
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33
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Rishi G, Subramaniam VN. Biology of the iron efflux transporter, ferroportin. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2020; 123:1-16. [PMID: 33485480 DOI: 10.1016/bs.apcsb.2020.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Iron, the most common metal in the earth, is also an essential component for almost all living organisms. While these organisms require iron for many biological processes, too much or too little iron itself poses many issues; this is most easily recognized in human beings. The control of body iron levels is thus an important metabolic process which is regulated essentially by controlling the expression, activity and levels of the iron transporter ferroportin. Ferroportin is the only known iron exporter. The function and activity of ferroportin is influenced by its interaction with the iron-regulatory peptide hepcidin, which itself is regulated by many factors. Here we review the current state of understanding of the mechanisms that regulate ferroportin and its function.
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Affiliation(s)
- Gautam Rishi
- Hepatogenomics Research Group, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - V Nathan Subramaniam
- Hepatogenomics Research Group, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, QLD, Australia
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34
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Deshpande CN, Azucenas CR, Qiao B, Nomura N, Xin V, Font J, Iwata S, Ganz T, Nemeth E, Mackenzie B, Jormakka M. Isolation and thermal stabilization of mouse ferroportin. FEBS Open Bio 2020; 11:26-34. [PMID: 33190422 PMCID: PMC7780100 DOI: 10.1002/2211-5463.13039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 10/30/2020] [Accepted: 11/12/2020] [Indexed: 12/03/2022] Open
Abstract
Ferroportin (Fpn) is an essential mammalian iron transporter that is negatively regulated by the hormone hepcidin. Our current molecular understanding of Fpn‐mediated iron efflux and regulation is limited due to a lack of biochemical, biophysical and high‐resolution structural studies. A critical step towards understanding the transport mechanism of Fpn is to obtain sufficient quantities of pure and stable protein for downstream studies. As such, we detail here an expression and purification protocol for mouse Fpn yielding milligram quantities of pure protein. We have generated deletion constructs exhibiting enhanced thermal stability and which retained iron‐transport activity and hepcidin responsiveness, providing a platform for further biophysical studies of Fpn.
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Affiliation(s)
| | - Corbin R Azucenas
- Department of Pharmacology & Systems Physiology, University of Cincinnati College of Medicine, OH.,Medical Sciences Baccalaureate Program, University of Cincinnati College of Medicine, OH, USA
| | - Bo Qiao
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Norimichi Nomura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Japan
| | - Vicky Xin
- Structural Biology Program, Centenary Institute, Sydney, NSW, Australia
| | - Josep Font
- Structural Biology Program, Centenary Institute, Sydney, NSW, Australia
| | - So Iwata
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Japan
| | - Tomas Ganz
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Department of Pathology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Elizabeta Nemeth
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Bryan Mackenzie
- Medical Sciences Baccalaureate Program, University of Cincinnati College of Medicine, OH, USA.,Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Mika Jormakka
- Structural Biology Program, Centenary Institute, Sydney, NSW, Australia
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35
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The role of cellular iron deficiency in controlling iron export. Biochim Biophys Acta Gen Subj 2020; 1865:129829. [PMID: 33340587 DOI: 10.1016/j.bbagen.2020.129829] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 11/25/2020] [Accepted: 12/14/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Iron export via the transport protein ferroportin (Fpn) plays a critical role in the regulation of dietary iron absorption and iron recycling in macrophages. Fpn plasma membrane expression is controlled by the hepatic iron-regulated hormone hepcidin in response to high iron availability and inflammation. Hepcidin binds to the central cavity of the Fpn transporter to block iron export either directly or by inducing Fpn internalization and lysosomal degradation. Here, we investigated whether iron deficiency affects Fpn protein turnover. METHODS We ectopically expressed Fpn in HeLa cells and used cycloheximide chase experiments to study basal and hepcidin-induced Fpn degradation under extracellular and intracellular iron deficiency. CONCLUSIONS/GENERAL SIGNIFICANCE We show that iron deficiency does not affect basal Fpn turnover but causes a significant delay in hepcidin-induced degradation when cytosolic iron levels are low. These data have important mechanistic implications supporting the hypothesis that iron export is required for efficient targeting of Fpn by hepcidin. Additionally, we show that Fpn degradation is not involved in protecting cells from intracellular iron deficiency.
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36
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Sorribes-Dauden R, Peris D, Martínez-Pastor MT, Puig S. Structure and function of the vacuolar Ccc1/VIT1 family of iron transporters and its regulation in fungi. Comput Struct Biotechnol J 2020; 18:3712-3722. [PMID: 33304466 PMCID: PMC7714665 DOI: 10.1016/j.csbj.2020.10.044] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/28/2020] [Accepted: 10/31/2020] [Indexed: 02/06/2023] Open
Abstract
Iron is an essential micronutrient for most living beings since it participates as a redox active cofactor in many biological processes including cellular respiration, lipid biosynthesis, DNA replication and repair, and ribosome biogenesis and recycling. However, when present in excess, iron can participate in Fenton reactions and generate reactive oxygen species that damage cells at the level of proteins, lipids and nucleic acids. Organisms have developed different molecular strategies to protect themselves against the harmful effects of high concentrations of iron. In the case of fungi and plants, detoxification mainly occurs by importing cytosolic iron into the vacuole through the Ccc1/VIT1 iron transporter. New sequenced genomes and bioinformatic tools are facilitating the functional characterization, evolution and ecological relevance of metabolic pathways and homeostatic networks across the Tree of Life. Sequence analysis shows that Ccc1/VIT1 homologs are widely distributed among organisms with the exception of animals. The recent elucidation of the crystal structure of a Ccc1/VIT1 plant ortholog has enabled the identification of both conserved and species-specific motifs required for its metal transport mechanism. Moreover, recent studies in the yeast Saccharomyces cerevisiae have also revealed that multiple transcription factors including Yap5 and Msn2/Msn4 contribute to the expression of CCC1 in high-iron conditions. Interestingly, Malaysian S. cerevisiae strains express a partially functional Ccc1 protein that renders them sensitive to iron. Different regulatory mechanisms have been described for non-Saccharomycetaceae Ccc1 homologs. The characterization of Ccc1/VIT1 proteins is of high interest in the development of biofortified crops and the protection against microbial-derived diseases.
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Key Words
- BLOSUM, BLOcks SUbstitution Matrix
- CBC, CCAAT-binding core complex
- CRD, Cysteine-rich domain
- CS, Consistency score
- Ccc1
- Cg, Candida glabrata
- Eg, Eucalyptus grandis
- Fe, Iron
- Fungi
- H, Helix
- Hap, Heme activator protein
- ISC, Iron-sulfur luster
- Iron detoxification
- Iron regulation
- Iron transport
- MAFFT, Multiple Alignment using Fast Fourier Transform
- MBD, Metal-binding domain
- ML, Maximum-likelihood
- NRAMP, Natural Resistance-Associated Macrophage Protein
- Plants
- ROS, Reactive oxygen species
- TMD, Transmembrane domain
- VIT, Vacuolar iron transporter
- VIT1
- VTL, Vacuolar iron transporter-like
- Vacuole
- YRE, Yap response elements
- Yeast
- bZIP, basic leucine-zipper
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Affiliation(s)
- Raquel Sorribes-Dauden
- Departamento de Bioquímica y Biología Molecular, Universitat de València, Burjassot, Valencia, Spain
| | - David Peris
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | | | - Sergi Puig
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
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37
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Structural basis of ion transport and inhibition in ferroportin. Nat Commun 2020; 11:5686. [PMID: 33173040 PMCID: PMC7655804 DOI: 10.1038/s41467-020-19458-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 10/15/2020] [Indexed: 01/01/2023] Open
Abstract
Ferroportin is an iron exporter essential for releasing cellular iron into circulation. Ferroportin is inhibited by a peptide hormone, hepcidin. In humans, mutations in ferroportin lead to ferroportin diseases that are often associated with accumulation of iron in macrophages and symptoms of iron deficiency anemia. Here we present the structures of the ferroportin from the primate Philippine tarsier (TsFpn) in the presence and absence of hepcidin solved by cryo-electron microscopy. TsFpn is composed of two domains resembling a clamshell and the structure defines two metal ion binding sites, one in each domain. Both structures are in an outward-facing conformation, and hepcidin binds between the two domains and reaches one of the ion binding sites. Functional studies show that TsFpn is an electroneutral H+/Fe2+ antiporter so that transport of each Fe2+ is coupled to transport of two H+ in the opposite direction. Perturbing either of the ion binding sites compromises the coupled transport of H+ and Fe2+. These results establish the structural basis of metal ion binding, transport and inhibition in ferroportin and provide a blueprint for targeting ferroportin in pharmacological intervention of ferroportin diseases. Ferroportin is an iron exporter essential for releasing cellular iron into circulation and is inhibited by a peptide hormone, hepcidin. Here authors present cryo-EM structures of the ferroportin from the primate Philippine tarsier (TsFpn) with and without hepcidin and show that TsFpn is an electroneutral H+ /Fe2+ antiporter.
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38
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Krzywoszyńska K, Witkowska D, Świątek-Kozłowska J, Szebesczyk A, Kozłowski H. General Aspects of Metal Ions as Signaling Agents in Health and Disease. Biomolecules 2020; 10:biom10101417. [PMID: 33036384 PMCID: PMC7600656 DOI: 10.3390/biom10101417] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/30/2020] [Accepted: 10/02/2020] [Indexed: 02/07/2023] Open
Abstract
This review focuses on the current knowledge on the involvement of metal ions in signaling processes within the cell, in both physiological and pathological conditions. The first section is devoted to the recent discoveries on magnesium and calcium-dependent signal transduction-the most recognized signaling agents among metals. The following sections then describe signaling pathways where zinc, copper, and iron play a key role. There are many systems in which changes in intra- and extra-cellular zinc and copper concentrations have been linked to important downstream events, especially in nervous signal transduction. Iron signaling is mostly related with its homeostasis. However, it is also involved in a recently discovered type of programmed cell death, ferroptosis. The important differences in metal ion signaling, and its disease-leading alterations, are also discussed.
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Affiliation(s)
- Karolina Krzywoszyńska
- Institute of Health Sciences, University of Opole, 68 Katowicka St., 45-060 Opole, Poland; (J.Ś.-K.); (A.S.); (H.K.)
- Correspondence: (K.K.); (D.W.); Tel.: +48-77-44-23-549 (K.K); +48-77-44-23-548 (D.W.)
| | - Danuta Witkowska
- Institute of Health Sciences, University of Opole, 68 Katowicka St., 45-060 Opole, Poland; (J.Ś.-K.); (A.S.); (H.K.)
- Correspondence: (K.K.); (D.W.); Tel.: +48-77-44-23-549 (K.K); +48-77-44-23-548 (D.W.)
| | - Jolanta Świątek-Kozłowska
- Institute of Health Sciences, University of Opole, 68 Katowicka St., 45-060 Opole, Poland; (J.Ś.-K.); (A.S.); (H.K.)
| | - Agnieszka Szebesczyk
- Institute of Health Sciences, University of Opole, 68 Katowicka St., 45-060 Opole, Poland; (J.Ś.-K.); (A.S.); (H.K.)
| | - Henryk Kozłowski
- Institute of Health Sciences, University of Opole, 68 Katowicka St., 45-060 Opole, Poland; (J.Ś.-K.); (A.S.); (H.K.)
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie St., 50-383 Wrocław, Poland
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Escudero V, Abreu I, Tejada-Jiménez M, Rosa-Núñez E, Quintana J, Prieto RI, Larue C, Wen J, Villanova J, Mysore KS, Argüello JM, Castillo-Michel H, Imperial J, González-Guerrero M. Medicago truncatula Ferroportin2 mediates iron import into nodule symbiosomes. THE NEW PHYTOLOGIST 2020; 228:194-209. [PMID: 32367515 DOI: 10.1111/nph.16642] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 04/27/2020] [Indexed: 06/11/2023]
Abstract
Iron is an essential cofactor for symbiotic nitrogen fixation, required by many of the enzymes involved, including signal transduction proteins, O2 homeostasis systems, and nitrogenase itself. Consequently, host plants have developed a transport network to deliver essential iron to nitrogen-fixing nodule cells. Ferroportin family members in model legume Medicago truncatula were identified and their expression was determined. Yeast complementation assays, immunolocalization, characterization of a tnt1 insertional mutant line, and synchrotron-based X-ray fluorescence assays were carried out in the nodule-specific M. truncatula ferroportin Medicago truncatula nodule-specific gene Ferroportin2 (MtFPN2) is an iron-efflux protein. MtFPN2 is located in intracellular membranes in the nodule vasculature and in inner nodule tissues, as well as in the symbiosome membranes in the interzone and early-fixation zone of the nodules. Loss-of-function of MtFPN2 alters iron distribution and speciation in nodules, reducing nitrogenase activity and biomass production. Using promoters with different tissular activity to drive MtFPN2 expression in MtFPN2 mutants, we determined that expression in the inner nodule tissues is sufficient to restore the phenotype, while confining MtFPN2 expression to the vasculature did not improve the mutant phenotype. These data indicate that MtFPN2 plays a primary role in iron delivery to nitrogen-fixing bacteroids in M. truncatula nodules.
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Affiliation(s)
- Viviana Escudero
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid, Pozuelo de Alarcón (Madrid), 28223, Spain
| | - Isidro Abreu
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid, Pozuelo de Alarcón (Madrid), 28223, Spain
| | - Manuel Tejada-Jiménez
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid, Pozuelo de Alarcón (Madrid), 28223, Spain
| | - Elena Rosa-Núñez
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid, Pozuelo de Alarcón (Madrid), 28223, Spain
| | - Julia Quintana
- Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Rosa Isabel Prieto
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid, Pozuelo de Alarcón (Madrid), 28223, Spain
| | - Camille Larue
- EcoLab, CNRS, Université de Toulouse, Toulouse, 31326, France
| | - Jiangqi Wen
- Noble Research Institute, Ardmore, OK, 73401, USA
| | - Julie Villanova
- ID16 Beamline. European Synchrotron Radiation Facility, Grenoble, 38043, France
| | | | | | | | - Juan Imperial
- Instituto de Ciencias Agrarias, Consejo Superior de Investigaciones Científicas, Madrid, 28006, Spain
| | - Manuel González-Guerrero
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid, Pozuelo de Alarcón (Madrid), 28223, Spain
- Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Madrid, 28040, Spain
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40
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Tortosa V, Bonaccorsi di Patti MC, Iacovelli F, Pasquadibisceglie A, Falconi M, Musci G, Polticelli F. Dynamical Behavior of the Human Ferroportin Homologue from Bdellovibrio bacteriovorus: Insight into the Ligand Recognition Mechanism. Int J Mol Sci 2020; 21:E6785. [PMID: 32947891 PMCID: PMC7555787 DOI: 10.3390/ijms21186785] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/14/2020] [Accepted: 09/15/2020] [Indexed: 01/07/2023] Open
Abstract
Members of the major facilitator superfamily of transporters (MFS) play an essential role in many physiological processes such as development, neurotransmission, and signaling. Aberrant functions of MFS proteins are associated with several diseases, including cancer, schizophrenia, epilepsy, amyotrophic lateral sclerosis and Alzheimer's disease. MFS transporters are also involved in multidrug resistance in bacteria and fungi. The structures of most MFS members, especially those of members with significant physiological relevance, are yet to be solved. The lack of structural and functional information impedes our detailed understanding, and thus the pharmacological targeting, of these transporters. To improve our knowledge on the mechanistic principles governing the function of MSF members, molecular dynamics (MD) simulations were performed on the inward-facing and outward-facing crystal structures of the human ferroportin homologue from the Gram-negative bacterium Bdellovibrio bacteriovorus (BdFpn). Several simulations with an excess of iron ions were also performed to explore the relationship between the protein's dynamics and the ligand recognition mechanism. The results reinforce the existence of the alternating-access mechanism already described for other MFS members. In addition, the reorganization of salt bridges, some of which are conserved in several MFS members, appears to be a key molecular event facilitating the conformational change of the transporter.
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Affiliation(s)
- Valentina Tortosa
- Department of Sciences, Roma Tre University, 00146 Rome, Italy; (V.T.); (A.P.)
| | | | - Federico Iacovelli
- Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy; (F.I.); (M.F.)
| | | | - Mattia Falconi
- Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy; (F.I.); (M.F.)
| | - Giovanni Musci
- Department Biosciences and Territory, University of Molise, 86090 Pesche, Italy;
| | - Fabio Polticelli
- Department of Sciences, Roma Tre University, 00146 Rome, Italy; (V.T.); (A.P.)
- National Institute of Nuclear Physics, Roma Tre Section, 00146 Rome, Italy
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Billesbølle CB, Azumaya CM, Kretsch RC, Powers AS, Gonen S, Schneider S, Arvedson T, Dror RO, Cheng Y, Manglik A. Structure of hepcidin-bound ferroportin reveals iron homeostatic mechanisms. Nature 2020; 586:807-811. [PMID: 32814342 PMCID: PMC7906036 DOI: 10.1038/s41586-020-2668-z] [Citation(s) in RCA: 157] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 07/15/2020] [Indexed: 01/01/2023]
Abstract
The serum iron level in humans is tightly controlled by the action of the hormone hepcidin on the iron efflux transporter ferroportin. Hepcidin regulates iron absorption and recycling by inducing ferroportin internalization and degradation1. Aberrant ferroportin activity can lead to diseases of iron overload, like hemochromatosis, or iron limitation anemias2. Here, we determined cryogenic electron microscopy (cryo-EM) structures of ferroportin in lipid nanodiscs, both in the apo state and in complex with cobalt, an iron mimetic, and hepcidin. These structures and accompanying molecular dynamics simulations identify two metal binding sites within the N- and C-domains of ferroportin. Hepcidin binds ferroportin in an outward-open conformation and completely occludes the iron efflux pathway to inhibit transport. The carboxy-terminus of hepcidin directly contacts the divalent metal in the ferroportin C-domain. We further show that hepcidin binding to ferroportin is coupled to iron binding, with an 80-fold increase in hepcidin affinity in the presence of iron. These results suggest a model for hepcidin regulation of ferroportin, where only iron loaded ferroportin molecules are targeted for degradation. More broadly, our structural and functional insights are likely to enable more targeted manipulation of the hepcidin-ferroportin axis in disorders of iron homeostasis.
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Affiliation(s)
- Christian B Billesbølle
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Caleigh M Azumaya
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Rachael C Kretsch
- Department of Computer Science, Stanford University, Stanford, CA, USA.,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.,Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA.,Biophysics Program, Stanford University, Stanford, CA, USA
| | - Alexander S Powers
- Department of Computer Science, Stanford University, Stanford, CA, USA.,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.,Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA.,Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Shane Gonen
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.,Howard Hughes Medical Institute, University of California San Francisco, San Francisco, CA, USA.,Department of Molecular Biology and Biochemistry, University of California, Irvine, Biological Sciences III, Irvine, CA, USA
| | - Simon Schneider
- Institute of Biochemistry, Goethe University Frankfurt, Max-von-Laue-Straße 9, Frankfurt am Main, Germany
| | - Tara Arvedson
- Department of Oncology Research, Amgen Inc., South San Francisco, CA, USA
| | - Ron O Dror
- Department of Computer Science, Stanford University, Stanford, CA, USA.,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.,Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA.,Biophysics Program, Stanford University, Stanford, CA, USA
| | - Yifan Cheng
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA. .,Howard Hughes Medical Institute, University of California San Francisco, San Francisco, CA, USA.
| | - Aashish Manglik
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA. .,Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA, USA.
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42
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Viveiros A, Panzer M, Baumgartner N, Schaefer B, Finkenstedt A, Henninger B, Theurl I, Nachbaur K, Weiss G, Haubner R, Decristoforo C, Tilg H, Zoller H. Reduced iron export associated with hepcidin resistance can explain the iron overload spectrum in ferroportin disease. Liver Int 2020; 40:1941-1951. [PMID: 32450003 PMCID: PMC7496278 DOI: 10.1111/liv.14539] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 05/14/2020] [Accepted: 05/18/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND & AIMS Ferroportin disease (FD) and hemochromatosis type 4 (HH4) are associated with variants in the ferroportin-encoding gene SLC40A1. Both phenotypes are characterized by iron overload despite being caused by distinct variants that either mediate reduced cellular iron export in FD or resistance against hepcidin-induced inactivation of ferroportin in HH4. The aim of this study was to assess if reduced iron export also confers hepcidin resistance and causes iron overload in FD associated with the R178Q variant. METHODS The ferroportin disease variants R178Q andA77D and the HH4-variant C326Y were overexpressed in HEK-293T cells and subcellular localization was characterized by confocal microscopy and flow cytometry. Iron export and cytosolic ferritin were measured as markers of iron transport and radioligand binding studies were performed. The hepcidin-ferroportin axis was assessed by ferritin/hepcidin correlation in patients with different iron storage diseases. RESULTS In the absence of hepcidin, the R178Q and A77D variants exported less iron when compared to normal and C326Y ferroportin. In the presence of hepcidin, the R178Q and C326Y, but not the A77D-variant, exported more iron than cells expressing normal ferroportin. Regression analysis of serum hepcidin and ferritin in patients with iron overload are compatible with hepcidin deficiency in HFE hemochromatosis and hepcidin resistance in R178Q FD. CONCLUSIONS These results support a novel concept that in certain FD variants reduced iron export and hepcidin resistance could be interlinked. Evasion of mutant ferroportin from hepcidin-mediated regulation could result in uncontrolled iron absorption and iron overload despite reduced transport function.
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Affiliation(s)
- André Viveiros
- Department of Medicine IMedical University and University Hospital of InnsbruckInnsbruckAustria
| | - Marlene Panzer
- Department of Medicine IMedical University and University Hospital of InnsbruckInnsbruckAustria
| | - Nadja Baumgartner
- Department of Medicine IMedical University and University Hospital of InnsbruckInnsbruckAustria
| | - Benedikt Schaefer
- Department of Medicine IMedical University and University Hospital of InnsbruckInnsbruckAustria
| | - Armin Finkenstedt
- Department of Medicine IMedical University and University Hospital of InnsbruckInnsbruckAustria
| | - Benjamin Henninger
- Department of RadiologyMedical University and University Hospital of InnsbruckInnsbruckAustria
| | - Igor Theurl
- Department of Medicine IIMedical University and University Hospital of InnsbruckInnsbruckAustria
| | - Karin Nachbaur
- Department of Medicine IMedical University and University Hospital of InnsbruckInnsbruckAustria
| | - Günter Weiss
- Department of Medicine IIMedical University and University Hospital of InnsbruckInnsbruckAustria
| | - Roland Haubner
- Department of Nuclear MedicineMedical University and University Hospital of InnsbruckInnsbruckAustria
| | - Clemens Decristoforo
- Department of Nuclear MedicineMedical University and University Hospital of InnsbruckInnsbruckAustria
| | - Herbert Tilg
- Department of Medicine IMedical University and University Hospital of InnsbruckInnsbruckAustria
| | - Heinz Zoller
- Department of Medicine IMedical University and University Hospital of InnsbruckInnsbruckAustria
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43
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Ehsan M, Katsube S, Cecchetti C, Du Y, Mortensen JS, Wang H, Nygaard A, Ghani L, Loland CJ, Kobilka BK, Byrne B, Guan L, Chae PS. New Malonate-Derived Tetraglucoside Detergents for Membrane Protein Stability. ACS Chem Biol 2020; 15:1697-1707. [PMID: 32501004 DOI: 10.1021/acschembio.0c00316] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Membrane proteins are widely studied in detergent micelles, a membrane-mimetic system formed by amphiphilic compounds. However, classical detergents have serious limitations in their utility, particularly for unstable proteins such as eukaryotic membrane proteins and membrane protein complexes, and thus, there is an unmet need for novel amphiphiles with enhanced ability to stabilize membrane proteins. Here, we developed a new class of malonate-derived detergents with four glucosides, designated malonate-derived tetra-glucosides (MTGs), and compared these new detergents with previously reported octyl glucose neopentyl glycol (OGNG) and n-dodecyl-β-d-maltoside (DDM). When tested with two G-protein coupled receptors (GPCRs) and three transporters, a couple of MTGs consistently conferred enhanced stability to all tested proteins compared to DDM and OGNG. As a result of favorable behaviors for a range of membrane proteins, these MTGs have substantial potential for membrane protein research. This study additionally provides a new detergent design principle based on the effect of a polar functional group (i.e., ether) on protein stability depending on its position in the detergent scaffold.
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Affiliation(s)
- Muhammad Ehsan
- Department of Bionanotechnology, Hanyang University, Ansan, 15588, Korea
| | - Satoshi Katsube
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States
| | - Cristina Cecchetti
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Yang Du
- School of Life and Health Sciences, Kobilka Institute of Innovative Drug Discovery, Chinese University of Hong Kong, 2001 Longxiang Avenue, Shenzhen, Guangdong 518172, China
| | - Jonas S. Mortensen
- Department of Neuroscience, University of Copenhagen, Copenhagen, DK-2200, Denmark
| | - Haoqing Wang
- Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, United States
| | - Andreas Nygaard
- Department of Neuroscience, University of Copenhagen, Copenhagen, DK-2200, Denmark
| | - Lubna Ghani
- Department of Bionanotechnology, Hanyang University, Ansan, 15588, Korea
| | - Claus J. Loland
- Department of Neuroscience, University of Copenhagen, Copenhagen, DK-2200, Denmark
| | - Brian K. Kobilka
- Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, United States
| | - Bernadette Byrne
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Lan Guan
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States
| | - Pil Seok Chae
- Department of Bionanotechnology, Hanyang University, Ansan, 15588, Korea
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44
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Wang SC, Davejan P, Hendargo KJ, Javadi-Razaz I, Chou A, Yee DC, Ghazi F, Lam KJK, Conn AM, Madrigal A, Medrano-Soto A, Saier MH. Expansion of the Major Facilitator Superfamily (MFS) to include novel transporters as well as transmembrane-acting enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183277. [PMID: 32205149 DOI: 10.1016/j.bbamem.2020.183277] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/14/2020] [Accepted: 03/17/2020] [Indexed: 12/14/2022]
Abstract
The Major Facilitator Superfamily (MFS) is currently the largest characterized superfamily of transmembrane secondary transport proteins. Its diverse members are found in essentially all organisms in the biosphere and function by uniport, symport, and/or antiport mechanisms. In 1993 we first named and described the MFS which then consisted of 5 previously known families that had not been known to be related, and by 2012 we had identified a total of 74 families, classified phylogenetically within the MFS, all of which included only transport proteins. This superfamily has since expanded to 89 families, all included under TC# 2.A.1, and a few transporter families outside of TC# 2.A.1 were identified as members of the MFS. In this study, we assign nine previously unclassified protein families in the Transporter Classification Database (TCDB; http://www.tcdb.org) to the MFS based on multiple criteria and bioinformatic methodologies. In addition, we find integral membrane domains distantly related to partial or full-length MFS permeases in Lysyl tRNA Synthases (TC# 9.B.111), Lysylphosphatidyl Glycerol Synthases (TC# 4.H.1), and cytochrome b561 transmembrane electron carriers (TC# 5.B.2). Sequence alignments, overlap of hydropathy plots, compatibility of repeat units, similarity of complexity profiles of transmembrane segments, shared protein domains and 3D structural similarities between transport proteins were analyzed to assist in inferring homology. The MFS now includes 105 families.
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Affiliation(s)
- Steven C Wang
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, United States of America
| | - Pauldeen Davejan
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, United States of America
| | - Kevin J Hendargo
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, United States of America
| | - Ida Javadi-Razaz
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, United States of America
| | - Amy Chou
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, United States of America
| | - Daniel C Yee
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, United States of America
| | - Faezeh Ghazi
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, United States of America
| | - Katie Jing Kay Lam
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, United States of America
| | - Adam M Conn
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, United States of America
| | - Assael Madrigal
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, United States of America
| | - Arturo Medrano-Soto
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, United States of America
| | - Milton H Saier
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, United States of America.
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45
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Manolova V, Nyffenegger N, Flace A, Altermatt P, Varol A, Doucerain C, Sundstrom H, Dürrenberger F. Oral ferroportin inhibitor ameliorates ineffective erythropoiesis in a model of β-thalassemia. J Clin Invest 2019; 130:491-506. [PMID: 31638596 PMCID: PMC6934209 DOI: 10.1172/jci129382] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 10/08/2019] [Indexed: 01/01/2023] Open
Abstract
β-Thalassemia is a genetic anemia caused by partial or complete loss of β-globin synthesis, leading to ineffective erythropoiesis and RBCs with a short life span. Currently, there is no efficacious oral medication modifying anemia for patients with β-thalassemia. The inappropriately low levels of the iron regulatory hormone hepcidin enable excessive iron absorption by ferroportin, the unique cellular iron exporter in mammals, leading to organ iron overload and associated morbidities. Correction of unbalanced iron absorption and recycling by induction of hepcidin synthesis or treatment with hepcidin mimetics ameliorates β-thalassemia. However, hepcidin modulation or replacement strategies currently in clinical development all require parenteral drug administration. We identified oral ferroportin inhibitors by screening a library of small molecular weight compounds for modulators of ferroportin internalization. Restricting iron availability by VIT-2763, the first clinical stage oral ferroportin inhibitor, ameliorated anemia and the dysregulated iron homeostasis in the Hbbth3/+ mouse model of β-thalassemia intermedia. VIT-2763 not only improved erythropoiesis but also corrected the proportions of myeloid precursors in spleens of Hbbth3/+ mice. VIT-2763 is currently being developed as an oral drug targeting ferroportin for the treatment of β-thalassemia.
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46
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Guellec J, Elbahnsi A, Le Tertre M, Uguen K, Gourlaouen I, Férec C, Ka C, Callebaut I, Le Gac G. Molecular model of the ferroportin intracellular gate and implications for the human iron transport cycle and hemochromatosis type 4A. FASEB J 2019; 33:14625-14635. [PMID: 31690120 DOI: 10.1096/fj.201901857r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Ferroportin 1 (FPN1) is a major facilitator superfamily transporter that is essential for proper maintenance of human iron homeostasis at the systemic and cellular level. FPN1 dysfunction leads to the progressive accumulation of iron in reticuloendothelial cells, causing hemochromatosis type 4A (or ferroportin disease), an autosomal dominant disorder that displays large phenotypic heterogeneity. Although crystal structures have unveiled the outward- and inward-facing conformations of the bacterial homolog Bdellovibrio bacteriovorus Fpn (or Bd2019) and calcium has recently been identified as an essential cofactor, our molecular understanding of the iron transport mechanism remains incomplete. Here, we used a combination of molecular modeling, molecular dynamics simulations, and Ala site-directed mutagenesis, followed by complementary in vitro functional analyses, to explore the structural architecture of the human FPN1 intracellular gate. We reveal an interdomain network that involves 5 key amino acids and is likely very important for stability of the iron exporter facing the extracellular milieu. We also identify inter- and intradomain interactions that rely on the 2 Asp84 and Asn174 critical residues and do not exist in the bacterial homolog. These interactions are thought to play an important role in the modulation of conformational changes during the transport cycle. We interpret these results in the context of hemochromatosis type 4A, reinforcing the idea that different categories of loss-of-function mutations exist. Our findings provide an unprecedented view of the human FPN1 outward-facing structure and the particular function of the so-called "gating residues" in the mechanism of iron export.-Guellec, J., Elbahnsi, A., Le Tertre, M., Uguen, K., Gourlaouen, I., Férec, C., Ka, C., Callebaut, I., Le Gac, G. Molecular model of the ferroportin intracellular gate and implications for the human iron transport cycle and hemochromatosis type 4A.
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Affiliation(s)
- Julie Guellec
- INSERM Unité Mixte de Recherche (UMR) 1078, Etablissement Français du Sang-Bretagne, Institut Brestois Santé-Agro-Matière, Université Bretagne Loire-Université de Brest, Brest, France.,Association Gaetan Saleun, Brest, France
| | - Ahmad Elbahnsi
- Muséum National d'Histoire Naturelle, UMR Centre National de la Recherche Scientifique (CNRS) 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, Paris, France
| | - Marlène Le Tertre
- INSERM Unité Mixte de Recherche (UMR) 1078, Etablissement Français du Sang-Bretagne, Institut Brestois Santé-Agro-Matière, Université Bretagne Loire-Université de Brest, Brest, France.,Service de Génétique Médicale, Centre Hospitalier Régional et Universitaire (CHRU) de Brest, Hôpital Morvan, Brest, France; and
| | - Kévin Uguen
- INSERM Unité Mixte de Recherche (UMR) 1078, Etablissement Français du Sang-Bretagne, Institut Brestois Santé-Agro-Matière, Université Bretagne Loire-Université de Brest, Brest, France.,Service de Génétique Médicale, Centre Hospitalier Régional et Universitaire (CHRU) de Brest, Hôpital Morvan, Brest, France; and
| | - Isabelle Gourlaouen
- INSERM Unité Mixte de Recherche (UMR) 1078, Etablissement Français du Sang-Bretagne, Institut Brestois Santé-Agro-Matière, Université Bretagne Loire-Université de Brest, Brest, France
| | - Claude Férec
- INSERM Unité Mixte de Recherche (UMR) 1078, Etablissement Français du Sang-Bretagne, Institut Brestois Santé-Agro-Matière, Université Bretagne Loire-Université de Brest, Brest, France.,Association Gaetan Saleun, Brest, France.,Service de Génétique Médicale, Centre Hospitalier Régional et Universitaire (CHRU) de Brest, Hôpital Morvan, Brest, France; and
| | - Chandran Ka
- INSERM Unité Mixte de Recherche (UMR) 1078, Etablissement Français du Sang-Bretagne, Institut Brestois Santé-Agro-Matière, Université Bretagne Loire-Université de Brest, Brest, France.,Service de Génétique Médicale, Centre Hospitalier Régional et Universitaire (CHRU) de Brest, Hôpital Morvan, Brest, France; and.,Laboratory of Excellence Laboratory of Excellence (GR-Ex), Paris, France
| | - Isabelle Callebaut
- Muséum National d'Histoire Naturelle, UMR Centre National de la Recherche Scientifique (CNRS) 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, Paris, France
| | - Gérald Le Gac
- INSERM Unité Mixte de Recherche (UMR) 1078, Etablissement Français du Sang-Bretagne, Institut Brestois Santé-Agro-Matière, Université Bretagne Loire-Université de Brest, Brest, France.,Service de Génétique Médicale, Centre Hospitalier Régional et Universitaire (CHRU) de Brest, Hôpital Morvan, Brest, France; and.,Laboratory of Excellence Laboratory of Excellence (GR-Ex), Paris, France
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47
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Dziuba N, Hardy J, Lindahl PA. Low-molecular-mass iron complexes in blood plasma of iron-deficient pigs do not originate directly from nutrient iron. Metallomics 2019; 11:1900-1911. [PMID: 31603444 PMCID: PMC6854301 DOI: 10.1039/c9mt00152b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Nutrient iron entering the blood binds transferrin (TFN)d, which delivers iron to cells in the body. In healthy individuals, ∼30% of TFN is iron-bound while the remainder is unbound (apo-TFN). TFN saturates the plasma of individuals with iron-overload diseases such as hereditary hemochromatosis, prompting release of a poorly-defined low-molecular-mass (LMM) iron species called non-transferrin-bound iron (NTBI). An experiment was devised to directly detect NTBI in plasma of iron-deficient pigs and to assess the role of the liver which is known to bind NTBI. Catheters were surgically installed in the portal vein (PV) and either the caudal vena cava or the cranial vena cava. After the animals recovered, 57Fe II ascorbate was injected into the stomach via a feeding tube. Blood was removed through the catheters before and after injection; plasma became 57Fe-enriched after injection. 57Fe-enriched plasma was passed through a 10 kDa cutoff membrane and the flow-through solution (FTS) was subjected to size-exclusion liquid chromatography (LC). The eluent flowed into an ICP-MS where 56Fe and 57Fe were detected. Low-intensity iron peaks with masses of 400-1600 Da were observed, but none became enriched in 57Fe after injection. Rather, the injected 57Fe bound to apo-TFN. Viewed naively, this implies that nutrient-derived 57Fe in healthy mammals passes from the intestines to apo-TFN without first entering the blood as a LMM intermediate. In this case, nutrient iron exported from intestinal enterocytes of healthy individuals may quickly bind apo-TFN such that LMM iron species do not accumulate in blood plasma. Some 57Fe from the FTS may have adsorbed onto the column. In any event, the LMM iron species in plasma that eluted from the column must have originated from iron stored within the body, perhaps in macrophages - not directly from nutrient iron absorption. The liver absorbed and released LMM iron species, but the effect was modest, consistent with its role as a dynamic iron buffer. Passage through the liver also altered the distribution of different forms of TFN present in the PV.
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Affiliation(s)
- Nathaniel Dziuba
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Joanne Hardy
- Department of Veterinary Surgery, Veterinary Medicine and Biosciences, College Station, TX 77843-4475, USA
| | - Paul A Lindahl
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA and Department of Chemistry, Texas A&M University, College Station, TX 77843-3255, USA.
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48
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Vlasveld LT, Swinkels DW. Loss-of-function ferroportin disease: novel mechanistic insights and unanswered questions. Haematologica 2019; 103:1753-1755. [PMID: 30381414 DOI: 10.3324/haematol.2018.203315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- L Tom Vlasveld
- Department of Internal Medicine, Haaglanden Medical Center, Location Bronovo, The Hague
| | - Dorine W Swinkels
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
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49
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Vlasveld LT, Janssen R, Bardou-Jacquet E, Venselaar H, Hamdi-Roze H, Drakesmith H, Swinkels DW. Twenty Years of Ferroportin Disease: A Review or An Update of Published Clinical, Biochemical, Molecular, and Functional Features. Pharmaceuticals (Basel) 2019; 12:ph12030132. [PMID: 31505869 PMCID: PMC6789780 DOI: 10.3390/ph12030132] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/14/2019] [Accepted: 08/20/2019] [Indexed: 12/14/2022] Open
Abstract
Iron overloading disorders linked to mutations in ferroportin have diverse phenotypes in vivo, and the effects of mutations on ferroportin in vitro range from loss of function (LOF) to gain of function (GOF) with hepcidin resistance. We reviewed 359 patients with 60 ferroportin variants. Overall, macrophage iron overload and low/normal transferrin saturation (TSAT) segregated with mutations that caused LOF, while GOF mutations were linked to high TSAT and parenchymal iron accumulation. However, the pathogenicity of individual variants is difficult to establish due to the lack of sufficiently reported data, large inter-assay variability of functional studies, and the uncertainty associated with the performance of available in silico prediction models. Since the phenotypes of hepcidin-resistant GOF variants are indistinguishable from the other types of hereditary hemochromatosis (HH), these variants may be categorized as ferroportin-associated HH, while the entity ferroportin disease may be confined to patients with LOF variants. To further improve the management of ferroportin disease, we advocate for a global registry, with standardized clinical analysis and validation of the functional tests preferably performed in human-derived enterocytic and macrophagic cell lines. Moreover, studies are warranted to unravel the definite structure of ferroportin and the indispensable residues that are essential for functionality.
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Affiliation(s)
- L Tom Vlasveld
- Department of Internal Medicine, Haaglanden MC-Bronovo, 2597AX The Hague, The Netherlands
| | - Roel Janssen
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Edouard Bardou-Jacquet
- Liver Diseases Department, French Reference Centre for Rare Iron Overload Diseases of Genetic Origin, University Hospital Pontchaillou, 35033 Rennes, France
| | - Hanka Venselaar
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud, University Medical Center, P.O. Box 9191, 6500 HB Nijmegen, The Netherlands
| | - Houda Hamdi-Roze
- Molecular Genetics Department, French Reference Centre for Rare Iron Overload Diseases of Genetic Origin, University Hospital Pontchaillou, 35033 Rennes, France
| | - Hal Drakesmith
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX39DS, UK
| | - Dorine W Swinkels
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
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50
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Ehsan M, Du Y, Mortensen JS, Hariharan P, Qu Q, Ghani L, Das M, Grethen A, Byrne B, Skiniotis G, Keller S, Loland CJ, Guan L, Kobilka BK, Chae PS. Self-Assembly Behavior and Application of Terphenyl-Cored Trimaltosides for Membrane-Protein Studies: Impact of Detergent Hydrophobic Group Geometry on Protein Stability. Chemistry 2019; 25:11545-11554. [PMID: 31243822 DOI: 10.1002/chem.201902468] [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] [Received: 05/29/2019] [Indexed: 01/13/2023]
Abstract
Amphipathic agents are widely used in various fields including biomedical sciences. Micelle-forming detergents are particularly useful for in vitro membrane-protein characterization. As many conventional detergents are limited in their ability to stabilize membrane proteins, it is necessary to develop novel detergents to facilitate membrane-protein research. In the current study, we developed novel trimaltoside detergents with an alkyl pendant-bearing terphenyl unit as a hydrophobic group, designated terphenyl-cored maltosides (TPMs). We found that the geometry of the detergent hydrophobic group substantially impacts detergent self-assembly behavior, as well as detergent efficacy for membrane-protein stabilization. TPM-Vs, with a bent terphenyl group, were superior to the linear counterparts (TPM-Ls) at stabilizing multiple membrane proteins. The favorable protein stabilization efficacy of these bent TPMs is likely associated with a binding mode with membrane proteins distinct from conventional detergents and facial amphiphiles. When compared to n-dodecyl-β-d-maltoside (DDM), most TPMs were superior or comparable to this gold standard detergent at stabilizing membrane proteins. Notably, TPM-L3 was particularly effective at stabilizing the human β2 adrenergic receptor (β2 AR), a G-protein coupled receptor, and its complex with Gs protein. Thus, the current study not only provides novel detergent tools that are useful for membrane-protein study, but also suggests a critical role for detergent hydrophobic group geometry in governing detergent efficacy.
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Affiliation(s)
- Muhammad Ehsan
- Department of Bionanotechnology, Hanyang University, Ansan, 15588, Korea.,Current address: Department of Chemistry, Mirpur University of Science & Technology, Mirpur, AJK, 10250, Pakistan)
| | - Yang Du
- Molecular and Cellular Physiology, Stanford, CA, 94305, USA
| | - Jonas S Mortensen
- Department of Neuroscience, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Parameswaran Hariharan
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center Lubbock, TX, 79430, USA
| | - Qianhui Qu
- Molecular and Cellular Physiology and Structural Biology, Stanford University, Stanford, CA, 94305, USA
| | - Lubna Ghani
- Department of Bionanotechnology, Hanyang University, Ansan, 15588, Korea
| | - Manabendra Das
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
| | - Anne Grethen
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
| | - Bernadette Byrne
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Georgios Skiniotis
- Molecular and Cellular Physiology and Structural Biology, Stanford University, Stanford, CA, 94305, USA
| | - Sandro Keller
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
| | - Claus J Loland
- Department of Neuroscience, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Lan Guan
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center Lubbock, TX, 79430, USA
| | | | - Pil Seok Chae
- Department of Bionanotechnology, Hanyang University, Ansan, 15588, Korea
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