1
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Gouliaev F, Jonsson N, Gersing S, Lisby M, Lindorff-Larsen K, Hartmann-Petersen R. Destabilization and Degradation of a Disease-Linked PGM1 Protein Variant. Biochemistry 2024; 63:1423-1433. [PMID: 38743592 DOI: 10.1021/acs.biochem.4c00042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
PGM1-linked congenital disorder of glycosylation (PGM1-CDG) is an autosomal recessive disease characterized by several phenotypes, some of which are life-threatening. Research focusing on the disease-related variants of the α-D-phosphoglucomutase 1 (PGM1) protein has shown that several are insoluble in vitro and expressed at low levels in patient fibroblasts. Due to these observations, we hypothesized that some disease-linked PGM1 protein variants are structurally destabilized and subject to protein quality control (PQC) and rapid intracellular degradation. Employing yeast-based assays, we show that a disease-associated human variant, PGM1 L516P, is insoluble, inactive, and highly susceptible to ubiquitylation and rapid degradation by the proteasome. In addition, we show that PGM1 L516P forms aggregates in S. cerevisiae and that both the aggregation pattern and the abundance of PGM1 L516P are chaperone-dependent. Finally, using computational methods, we perform saturation mutagenesis to assess the impact of all possible single residue substitutions in the PGM1 protein. These analyses identify numerous missense variants with predicted detrimental effects on protein function and stability. We suggest that many disease-linked PGM1 variants are subject to PQC-linked degradation and that our in silico site-saturated data set may assist in the mechanistic interpretation of PGM1 variants.
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Affiliation(s)
- Frederik Gouliaev
- Department of Biology, University of Copenhagen, Ole Maalo̷es Vej 5, DK2200N Copenhagen, Denmark
| | - Nicolas Jonsson
- Department of Biology, University of Copenhagen, Ole Maalo̷es Vej 5, DK2200N Copenhagen, Denmark
| | - Sarah Gersing
- Department of Biology, University of Copenhagen, Ole Maalo̷es Vej 5, DK2200N Copenhagen, Denmark
| | - Michael Lisby
- Department of Biology, University of Copenhagen, Ole Maalo̷es Vej 5, DK2200N Copenhagen, Denmark
| | - Kresten Lindorff-Larsen
- Department of Biology, University of Copenhagen, Ole Maalo̷es Vej 5, DK2200N Copenhagen, Denmark
| | - Rasmus Hartmann-Petersen
- Department of Biology, University of Copenhagen, Ole Maalo̷es Vej 5, DK2200N Copenhagen, Denmark
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2
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Durin Z, Houdou M, Legrand D, Foulquier F. Metalloglycobiology: The power of metals in regulating glycosylation. Biochim Biophys Acta Gen Subj 2023; 1867:130412. [PMID: 37348823 DOI: 10.1016/j.bbagen.2023.130412] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/12/2023] [Accepted: 06/13/2023] [Indexed: 06/24/2023]
Abstract
The remarkable structural diversity of glycans that is exposed at the cell surface and generated along the secretory pathway is tightly regulated by several factors. The recent identification of human glycosylation diseases related to metal transporter defects opened a completely new field of investigation, referred to herein as "metalloglycobiology", on how metal changes can affect the glycosylation and hence the glycan structures that are produced. Although this field is in its infancy, this review aims to go through the different glycosylation steps/pathways that are metal dependent and that could be impacted by metal homeostasis dysregulations.
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Affiliation(s)
- Zoé Durin
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F- 59000 Lille, France
| | - Marine Houdou
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F- 59000 Lille, France
| | - Dominique Legrand
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F- 59000 Lille, France
| | - François Foulquier
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F- 59000 Lille, France.
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3
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Yan K, Stanley M, Kowalski B, Raimi OG, Ferenbach AT, Wei P, Fang W, van Aalten DMF. Genetic validation of Aspergillus fumigatus phosphoglucomutase as a viable therapeutic target in invasive aspergillosis. J Biol Chem 2022; 298:102003. [PMID: 35504355 PMCID: PMC9168620 DOI: 10.1016/j.jbc.2022.102003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 02/09/2023] Open
Abstract
Aspergillus fumigatus is the causative agent of invasive aspergillosis, an infection with mortality rates of up to 50%. The glucan-rich cell wall of A. fumigatus is a protective structure that is absent from human cells and is a potential target for antifungal treatments. Glucan is synthesized from the donor uridine diphosphate glucose, with the conversion of glucose-6-phosphate to glucose-1-phosphate by the enzyme phosphoglucomutase (PGM) representing a key step in its biosynthesis. Here, we explore the possibility of selectively targeting A. fumigatus PGM (AfPGM) as an antifungal treatment strategy. Using a promoter replacement strategy, we constructed a conditional pgm mutant and revealed that pgm is required for A. fumigatus growth and cell wall integrity. In addition, using a fragment screen, we identified the thiol-reactive compound isothiazolone fragment of PGM as targeting a cysteine residue not conserved in the human ortholog. Furthermore, through scaffold exploration, we synthesized a para-aryl derivative (ISFP10) and demonstrated that it inhibits AfPGM with an IC50 of 2 μM and exhibits 50-fold selectivity over the human enzyme. Taken together, our data provide genetic validation of PGM as a therapeutic target and suggest new avenues for inhibiting AfPGM using covalent inhibitors that could serve as tools for chemical validation.
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Affiliation(s)
- Kaizhou Yan
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Mathew Stanley
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Bartosz Kowalski
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Olawale G Raimi
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Andrew T Ferenbach
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Pingzhen Wei
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, China
| | - Wenxia Fang
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, China
| | - Daan M F van Aalten
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom.
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4
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Stiers KM, Owuocha LF, Beamer LJ. Effects of the T337M and G391V disease-related variants on human phosphoglucomutase 1: structural disruptions large and small. Acta Crystallogr F Struct Biol Commun 2022; 78:200-209. [PMID: 35506765 PMCID: PMC9067374 DOI: 10.1107/s2053230x22004174] [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: 02/17/2022] [Accepted: 04/19/2022] [Indexed: 11/10/2022] Open
Abstract
Phosphoglucomutase 1 (PGM1) plays a central role in glucose homeostasis in human cells. Missense variants of this enzyme cause an inborn error of metabolism, which is categorized as a congenital disorder of glycosylation. Here, two disease-related variants of PGM1, T337M and G391V, which are both located in domain 3 of the four-domain protein, were characterized via X-ray crystallography and biochemical assays. The studies show multiple impacts resulting from these dysfunctional variants, including both short- and long-range structural perturbations. In the T337M variant these are limited to a small shift in an active-site loop, consistent with reduced enzyme activity. In contrast, the G391V variant produces a cascade of structural perturbations, including displacement of both the catalytic phosphoserine and metal-binding loops. This work reinforces several themes that were found in prior studies of dysfunctional PGM1 variants, including increased structural flexibility and the outsized impacts of mutations affecting interdomain interfaces. The molecular mechanisms of PGM1 variants have implications for newly described inherited disorders of related enzymes.
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Affiliation(s)
- Kyle M. Stiers
- Biochemistry Department, University of Missouri, Columbia, MO 65211, USA
| | - Luckio F. Owuocha
- Biochemistry Department, University of Missouri, Columbia, MO 65211, USA
| | - Lesa J. Beamer
- Biochemistry Department, University of Missouri, Columbia, MO 65211, USA
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5
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Gustafsson R, Eckhard U, Ye W, Enbody ED, Pettersson M, Jemth P, Andersson L, Selmer M. Structure and Characterization of Phosphoglucomutase 5 from Atlantic and Baltic Herring-An Inactive Enzyme with Intact Substrate Binding. Biomolecules 2020; 10:E1631. [PMID: 33287293 PMCID: PMC7761743 DOI: 10.3390/biom10121631] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 11/27/2020] [Accepted: 11/30/2020] [Indexed: 12/31/2022] Open
Abstract
Phosphoglucomutase 5 (PGM5) in humans is known as a structural muscle protein without enzymatic activity, but detailed understanding of its function is lacking. PGM5 belongs to the alpha-D-phosphohexomutase family and is closely related to the enzymatically active metabolic enzyme PGM1. In the Atlantic herring, Clupea harengus, PGM5 is one of the genes strongly associated with ecological adaptation to the brackish Baltic Sea. We here present the first crystal structures of PGM5, from the Atlantic and Baltic herring, differing by a single substitution Ala330Val. The structure of PGM5 is overall highly similar to structures of PGM1. The structure of the Baltic herring PGM5 in complex with the substrate glucose-1-phosphate shows conserved substrate binding and active site compared to human PGM1, but both PGM5 variants lack phosphoglucomutase activity under the tested conditions. Structure comparison and sequence analysis of PGM5 and PGM1 from fish and mammals suggest that the lacking enzymatic activity of PGM5 is related to differences in active-site loops that are important for flipping of the reaction intermediate. The Ala330Val substitution does not alter structure or biophysical properties of PGM5 but, due to its surface-exposed location, could affect interactions with protein-binding partners.
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Affiliation(s)
- Robert Gustafsson
- Department of Cell and Molecular Biology, Uppsala University, BMC, Box 596, SE-751 24 Uppsala, Sweden; (R.G.); (U.E.)
| | - Ulrich Eckhard
- Department of Cell and Molecular Biology, Uppsala University, BMC, Box 596, SE-751 24 Uppsala, Sweden; (R.G.); (U.E.)
| | - Weihua Ye
- Department of Medical Biochemistry and Microbiology, Uppsala University, BMC, Box 582, SE-751 23 Uppsala, Sweden; (W.Y.); (E.D.E.); (M.P.); (P.J.); (L.A.)
| | - Erik D. Enbody
- Department of Medical Biochemistry and Microbiology, Uppsala University, BMC, Box 582, SE-751 23 Uppsala, Sweden; (W.Y.); (E.D.E.); (M.P.); (P.J.); (L.A.)
| | - Mats Pettersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, BMC, Box 582, SE-751 23 Uppsala, Sweden; (W.Y.); (E.D.E.); (M.P.); (P.J.); (L.A.)
| | - Per Jemth
- Department of Medical Biochemistry and Microbiology, Uppsala University, BMC, Box 582, SE-751 23 Uppsala, Sweden; (W.Y.); (E.D.E.); (M.P.); (P.J.); (L.A.)
| | - Leif Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, BMC, Box 582, SE-751 23 Uppsala, Sweden; (W.Y.); (E.D.E.); (M.P.); (P.J.); (L.A.)
- Department of Veterinary Integrative Biosciences, Texas A & M University, College Station, TX 77843, USA
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden
| | - Maria Selmer
- Department of Cell and Molecular Biology, Uppsala University, BMC, Box 596, SE-751 24 Uppsala, Sweden; (R.G.); (U.E.)
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6
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Liu XR, Bian WJ, Wang J, Ye TT, Li BM, Liu DT, Tang B, Deng WW, Shi YW, Su T, Yi YH, Liao WP. Heterozygous PGM3 Variants Are Associated With Idiopathic Focal Epilepsy With Incomplete Penetrance. Front Genet 2020; 11:559080. [PMID: 33193641 PMCID: PMC7597759 DOI: 10.3389/fgene.2020.559080] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 09/17/2020] [Indexed: 02/01/2023] Open
Abstract
Introduction Idiopathic focal epilepsy (IFE) is a group of self-limited epilepsies. The etiology for the majority of the patients with IFE remains elusive. We thus screened disease-causing variants in the patients with IFE. Methods Whole-exome sequencing was performed in a cohort of 323 patients with IFE. Protein modeling was performed to predict the effects of missense variants. The genotype-phenotype correlation of the newly defined causative gene was analyzed. Results Four novel heterozygous variants in PGM3, including two de novo variants, were identified in four unrelated individuals with IFE. The variants included one truncating variant (c.1432C > T/p.Q478X) and three missense variants (c.478C > T/p.P160S, c.1239C > G/p.N413K, and c.1659T > A/p.N553K), which had no allele frequency in the gnomAD database. The missense variants were predicted to be damaging and affect hydrogen bonds with surrounding amino acids. Mutations Q478X, P160S, and N413K were associated with benign childhood epilepsy with centrotemporal electroencephalograph (EEG) spikes. P160S and N413K were located in the inner side of the enzyme active center. Mutation N553K was associated with benign occipital epilepsy with incomplete penetrance, located in the C-terminal of Domain 4. Further analysis demonstrated that previously reported biallelic PGM3 mutations were associated with severe immunodeficiency and/or congenital disorder of glycosylation, commonly accompanied by neurodevelopmental abnormalities, while monoallelic mutations were associated with milder symptoms like IFE. Conclusion The genetic and molecular evidence from the present study implies that the PGM3 variants identified in IFE patients lead to defects of the PGM3 gene, suggesting that the PGM3 gene is potentially associated with epilepsy. The genotype-phenotype relationship of PGM3 mutations suggested a quantitative correlation between genetic impairment and phenotypic severity, which helps explain the mild symptoms and incomplete penetrance in individuals with IFE.
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Affiliation(s)
- Xiao-Rong Liu
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Institute, Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, of Neuroscience, Province and the Ministry of Education of China, Guangzhou, China
| | - Wen-Jun Bian
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Institute, Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, of Neuroscience, Province and the Ministry of Education of China, Guangzhou, China
| | - Jie Wang
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Institute, Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, of Neuroscience, Province and the Ministry of Education of China, Guangzhou, China
| | - Ting-Ting Ye
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Institute, Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, of Neuroscience, Province and the Ministry of Education of China, Guangzhou, China
| | - Bing-Mei Li
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Institute, Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, of Neuroscience, Province and the Ministry of Education of China, Guangzhou, China
| | - De-Tian Liu
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Institute, Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, of Neuroscience, Province and the Ministry of Education of China, Guangzhou, China
| | - Bin Tang
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Institute, Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, of Neuroscience, Province and the Ministry of Education of China, Guangzhou, China
| | - Wei-Wen Deng
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Institute, Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, of Neuroscience, Province and the Ministry of Education of China, Guangzhou, China
| | - Yi-Wu Shi
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Institute, Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, of Neuroscience, Province and the Ministry of Education of China, Guangzhou, China
| | - Tao Su
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Institute, Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, of Neuroscience, Province and the Ministry of Education of China, Guangzhou, China
| | - Yong-Hong Yi
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Institute, Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, of Neuroscience, Province and the Ministry of Education of China, Guangzhou, China
| | - Wei-Ping Liao
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Institute, Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, of Neuroscience, Province and the Ministry of Education of China, Guangzhou, China
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7
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Enzyme dysfunction at atomic resolution: Disease-associated variants of human phosphoglucomutase-1. Biochimie 2020; 183:44-48. [PMID: 32898648 DOI: 10.1016/j.biochi.2020.08.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/26/2020] [Accepted: 08/30/2020] [Indexed: 11/20/2022]
Abstract
Once experimentally prohibitive, structural studies of individual missense variants in proteins are increasingly feasible, and can provide a new level of insight into human genetic disease. One example of this is the recently identified inborn error of metabolism known as phosphoglucomutase-1 (PGM1) deficiency. Just as different variants of a protein can produce different patient phenotypes, they may also produce distinct biochemical phenotypes, affecting properties such as catalytic activity, protein stability, or 3D structure/dynamics. Experimental studies of missense variants, and particularly structural characterization, can reveal details of the underlying biochemical pathomechanisms of missense variants. Here, we review four examples of enzyme dysfunction observed in disease-related variants of PGM1. These studies are based on 11 crystal structures of wild-type (WT) and mutant enzymes, and multiple biochemical assays. Lessons learned include the value of comparing mutant and WT structures, synergy between structural and biochemical studies, and the rich understanding of molecular pathomechanism provided by experimental characterization relative to the use of predictive algorithms. We further note functional insights into the WT enzyme that can be gained from the study of pathogenic variants.
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8
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Conte F, Morava E, Bakar NA, Wortmann SB, Poerink AJ, Grunewald S, Crushell E, Al-Gazali L, de Vries MC, Mørkrid L, Hertecant J, Brocke Holmefjord KS, Kronn D, Feigenbaum A, Fingerhut R, Wong SY, van Scherpenzeel M, Voermans NC, Lefeber DJ. Phosphoglucomutase-1 deficiency: Early presentation, metabolic management and detection in neonatal blood spots. Mol Genet Metab 2020; 131:135-146. [PMID: 33342467 DOI: 10.1016/j.ymgme.2020.08.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/19/2020] [Accepted: 08/16/2020] [Indexed: 02/07/2023]
Abstract
Phosphoglucomutase 1 deficiency is a congenital disorder of glycosylation (CDG) with multiorgan involvement affecting carbohydrate metabolism, N-glycosylation and energy production. The metabolic management consists of dietary D-galactose supplementation that ameliorates hypoglycemia, hepatic dysfunction, endocrine anomalies and growth delay. Previous studies suggest that D-galactose administration in juvenile patients leads to more significant and long-lasting effects, stressing the urge of neonatal diagnosis (0-6 months of age). Here, we detail the early clinical presentation of PGM1-CDG in eleven infantile patients, and applied the modified Beutler test for screening of PGM1-CDG in neonatal dried blood spots (DBSs). All eleven infants presented episodic hypoglycemia and elevated transaminases, along with cleft palate and growth delay (10/11), muscle involvement (8/11), neurologic involvement (5/11), cardiac defects (2/11). Standard dietary measures for suspected lactose intolerance in four patients prior to diagnosis led to worsening of hypoglycemia, hepatic failure and recurrent diarrhea, which resolved upon D-galactose supplementation. To investigate possible differences in early vs. late clinical presentation, we performed the first systematic literature review for PGM1-CDG, which highlighted respiratory and gastrointestinal symptoms as significantly more diagnosed in neonatal age. The modified Butler-test successfully identified PGM1-CDG in DBSs from seven patients, including for the first time Guthrie cards from newborn screening, confirming the possibility of future inclusion of PGM1-CDG in neonatal screening programs. In conclusion, severe infantile morbidity of PGM1-CDG due to delayed diagnosis could be prevented by raising awareness on its early presentation and by inclusion in newborn screening programs, enabling early treatments and galactose-based metabolic management.
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Affiliation(s)
- Federica Conte
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands; Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Eva Morava
- Center of Individualized Medicine, Department of Clinical Genomics, Mayo Clinic, Rochester, USA; Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, USA.
| | - Nurulamin Abu Bakar
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands; Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Saskia B Wortmann
- Institute of Human Genetics, Technische Universität München, Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, Munich, Germany; Department of Pediatrics, Salzburger Landeskliniken (SALK) und Paracelsus Medical University (PMU), Salzburg, Austria.
| | - Anne Jonge Poerink
- Department of Pediatrics, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands; Department of Pediatrics, Medisch Centrum Twente, Enschede, the Netherlands.
| | - Stephanie Grunewald
- Great Ormond Street Hospital Foundation Trust, UCL Institute of Child Health, London, Great Britain, UK.
| | - Ellen Crushell
- National Centre for Inherited Metabolic Disorders, Children's Health Ireland at Temple Street and Crumlin Hospitals, Dublin, Ireland.
| | - Lihadh Al-Gazali
- Department of Pediatrics, College of Medicine & Health Sciences, UAE University, Al-Ain, United Arab Emirates.
| | - Maaike C de Vries
- Department of Pediatrics, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands.
| | - Lars Mørkrid
- Institute of Clinical Medicine, University of Oslo, Norway; Department of Medical Biochemistry, Oslo University Hospital-Rikshospitalet, Norway.
| | - Jozef Hertecant
- Genetics and Metabolics Service, Tawam Hospital, Al Ain, United Arab Emirates.
| | - Katja S Brocke Holmefjord
- Department. of Pediatric Habilitation/Department of Pediatric Neurology, Stavanger University Hospital, Stavanger, Norway.
| | - David Kronn
- Medical Genetic, Inherited Metabolic Diseases and Lysosomal Storage Disorders Center, Boston Children Hospital, MA, USA.
| | - Annette Feigenbaum
- Department of Pediatrics, University of California San Diego and Rady Children's Hospital, San Diego, CA, USA.
| | - Ralph Fingerhut
- Swiss Newborn Screening Laboratory, Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.
| | - Sunnie Y Wong
- Hayard Genetics Center, Tulane University School of Medicine, New Orleans, LA, United States of America.
| | - Monique van Scherpenzeel
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands; GlycoMScan B.V, Oss, the Netherlands.
| | - Nicol C Voermans
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Dirk J Lefeber
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands; Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
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9
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Stiers KM, Hansen RP, Daghlas BA, Mason KN, Zhu JS, Jakeman DL, Beamer LJ. A missense variant remote from the active site impairs stability of human phosphoglucomutase 1. J Inherit Metab Dis 2020; 43:861-870. [PMID: 32057119 DOI: 10.1002/jimd.12222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 02/04/2020] [Accepted: 02/10/2020] [Indexed: 12/18/2022]
Abstract
Missense variants of human phosphoglucomutase 1 (PGM1) cause the inherited metabolic disease known as PGM1 deficiency. This condition is categorised as both a glycogen storage disease and a congenital disorder of glycosylation. Approximately 20 missense variants of PGM1 are linked to PGM1 deficiency, and biochemical studies have suggested that they fall into two general categories: those affecting the active site and catalytic efficiency, and those that appear to impair protein folding and/or stability. In this study, we characterise a novel variant of Arg422, a residue distal from the active site of PGM1 and the site of a previously identified disease-related variant (Arg422Trp). In prior studies, the R422W variant was found to produce insoluble protein in a recombinant expression system, precluding further in vitro characterisation. Here we investigate an alternative variant of this residue, Arg422Gln, which is amenable to experimental characterisation presumably due to its more conservative physicochemical substitution. Biochemical, crystallographic, and computational studies of R422Q establish that this variant causes only minor changes in catalytic efficiency and 3D structure, but is nonetheless dramatically reduced in stability. Unexpectedly, binding of a substrate analog is found to further destabilise the protein, in contrast to its stabilising effect on wild-type PGM1 and several other missense variants. This work establishes Arg422 as a lynchpin residue for the stability of PGM1 and supports the impairment of protein stability as a pathomechanism for variants that cause PGM1 deficiency. SYNOPSIS: Biochemical and structural studies of a missense variant far from the active site of human PGM1 identify a residue with a key role in enzyme stability.
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Affiliation(s)
- Kyle M Stiers
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
| | - Reed P Hansen
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
| | - Bana A Daghlas
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
| | - Kelly N Mason
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
| | - Jian-She Zhu
- College of Pharmacy, Dalhousie University, Halifax, Nova Scotia, Canada
| | - David L Jakeman
- College of Pharmacy, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Lesa J Beamer
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
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10
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Structural basis for substrate and product recognition in human phosphoglucomutase-1 (PGM1) isoform 2, a member of the α-D-phosphohexomutase superfamily. Sci Rep 2020; 10:5656. [PMID: 32221390 PMCID: PMC7101342 DOI: 10.1038/s41598-020-62548-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 03/13/2020] [Indexed: 01/01/2023] Open
Abstract
Human phosphoglucomutase 1 (PGM1) is an evolutionary conserved enzyme that belongs to the ubiquitous and ancient α-d-phosphohexomutases, a large enzyme superfamily with members in all three domains of life. PGM1 catalyzes the bi-directional interconversion between α-d-glucose 1-phosphate (G1P) and α-d-glucose 6-phosphate (G6P), a reaction that is essential for normal carbohydrate metabolism and also important in the cytoplasmic biosynthesis of nucleotide sugars needed for glycan biosynthesis. Clinical studies have shown that mutations in the PGM1 gene may cause PGM1 deficiency, an inborn error of metabolism previously classified as a glycogen storage disease, and PGM1 deficiency was recently also shown to be a congenital disorder of glycosylation. Here we present three crystal structures of the isoform 2 variant of PGM1, both as a free enzyme and in complex with its substrate and product. The structures show the longer N-terminal of this PGM1 variant, and the ligand complex structures reveal for the first time the detailed structural basis for both G1P substrate and G6P product recognition by human PGM1. We also show that PGM1 and the paralogous gene PGM5 are the results of a gene duplication event in a common ancestor of jawed vertebrates, and, importantly, that both PGM1 isoforms are conserved and of functional significance in all vertebrates. Our finding that PGM1 encodes two equally conserved and functionally important isoforms in the human organism should be taken into account in the evaluation of disease-related missense mutations in patients in the future.
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Balakrishnan B, Verheijen J, Lupo A, Raymond K, Turgeon CT, Yang Y, Carter KL, Whitehead KJ, Kozicz T, Morava E, Lai K. A novel phosphoglucomutase-deficient mouse model reveals aberrant glycosylation and early embryonic lethality. J Inherit Metab Dis 2019; 42:998-1007. [PMID: 31077402 PMCID: PMC6739163 DOI: 10.1002/jimd.12110] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 05/06/2019] [Accepted: 05/08/2019] [Indexed: 01/01/2023]
Abstract
Patients with phosphoglucomutase (PGM1) deficiency, a congenital disorder of glycosylation (CDG) suffer from multiple disease phenotypes. Midline cleft defects are present at birth. Overtime, additional clinical phenotypes, which include severe hypoglycemia, hepatopathy, growth retardation, hormonal deficiencies, hemostatic anomalies, frequently lethal, early-onset of dilated cardiomyopathy and myopathy emerge, reflecting the central roles of the enzyme in (glycogen) metabolism and glycosylation. To delineate the pathophysiology of the tissue-specific disease phenotypes, we constructed a constitutive Pgm2 (mouse ortholog of human PGM1)-knockout (KO) mouse model using CRISPR-Cas9 technology. After multiple crosses between heterozygous parents, we were unable to identify homozygous life births in 78 newborn pups (P = 1.59897E-06), suggesting an embryonic lethality phenotype in the homozygotes. Ultrasound studies of the course of pregnancy confirmed Pgm2-deficient pups succumb before E9.5. Oral galactose supplementation (9 mg/mL drinking water) did not rescue the lethality. Biochemical studies of tissues and skin fibroblasts harvested from heterozygous animals confirmed reduced Pgm2 enzyme activity and abundance, but no change in glycogen content. However, glycomics analyses in serum revealed an abnormal glycosylation pattern in the Pgm2+/- animals, similar to that seen in PGM1-CDG.
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Affiliation(s)
- B Balakrishnan
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah
| | - J Verheijen
- Center for Individualized Medicine, Department of Clinical Genomics, and Biochemical Genetics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - A Lupo
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah
| | - K Raymond
- Center for Individualized Medicine, Department of Clinical Genomics, and Biochemical Genetics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - CT Turgeon
- Center for Individualized Medicine, Department of Clinical Genomics, and Biochemical Genetics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Y Yang
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah
| | - KL Carter
- Small Animal Ultrasound Core Facility, University of Utah School of Medicine, Salt Lake City, Utah
| | - KJ Whitehead
- Small Animal Ultrasound Core Facility, University of Utah School of Medicine, Salt Lake City, Utah
| | - T Kozicz
- Center for Individualized Medicine, Department of Clinical Genomics, and Biochemical Genetics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - E Morava
- Center for Individualized Medicine, Department of Clinical Genomics, and Biochemical Genetics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - K Lai
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah
- Corresponding Author: Kent Lai, Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, 295 Chipeta Way, Salt Lake City, Utah, U.S.A. 84108,
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Stiers KM, Beamer LJ. A Hotspot for Disease-Associated Variants of Human PGM1 Is Associated with Impaired Ligand Binding and Loop Dynamics. Structure 2018; 26:1337-1345.e3. [PMID: 30122451 DOI: 10.1016/j.str.2018.07.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 06/18/2018] [Accepted: 07/21/2018] [Indexed: 12/20/2022]
Abstract
Human phosphoglucomutase 1 (PGM1) plays a central role in cellular glucose homeostasis, catalyzing the conversion of glucose 1-phosphate and glucose 6-phosphate. Recently, missense variants of this enzyme were identified as causing an inborn error of metabolism, PGM1 deficiency, with features of a glycogen storage disease and a congenital disorder of glycosylation. Previous studies of selected PGM1 variants have revealed various mechanisms for enzyme dysfunction, including regions of structural disorder and side-chain rearrangements within the active site. Here, we examine variants within a substrate-binding loop in domain 4 (D4) of PGM1 that cause extreme impairment of activity. Biochemical, structural, and computational studies demonstrate multiple detrimental impacts resulting from these variants, including loss of conserved ligand-binding interactions and reduced mobility of the D4 loop, due to perturbation of its conformational ensemble. These potentially synergistic effects make this conserved ligand-binding loop a hotspot for disease-related variants in PGM1 and related enzymes.
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Affiliation(s)
- Kyle M Stiers
- Biochemistry Department, University of Missouri, 117 Schweitzer Hall, Columbia, MO 65211, USA
| | - Lesa J Beamer
- Biochemistry Department, University of Missouri, 117 Schweitzer Hall, Columbia, MO 65211, USA.
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Brás NF, Fernandes PA, Ramos MJ, Schwartz SD. Mechanistic Insights on Human Phosphoglucomutase Revealed by Transition Path Sampling and Molecular Dynamics Calculations. Chemistry 2018; 24:1978-1987. [PMID: 29131453 DOI: 10.1002/chem.201705090] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Indexed: 12/27/2022]
Abstract
Human α-phosphoglucomutase 1 (α-PGM) catalyzes the isomerization of glucose-1-phosphate into glucose-6-phosphate (G6P) through two sequential phosphoryl transfer steps with a glucose-1,6-bisphosphate (G16P) intermediate. Given that the release of G6P in the gluconeogenesis raises the glucose output levels, α-PGM represents a tempting pharmacological target for type 2 diabetes. Here, we provide the first theoretical study of the catalytic mechanism of human α-PGM. We performed transition-path sampling simulations to unveil the atomic details of the two catalytic chemical steps, which could be key for developing transition state (TS) analogue molecules with inhibitory properties. Our calculations revealed that both steps proceed through a concerted SN 2-like mechanism, with a loose metaphosphate-like TS. Even though experimental data suggests that the two steps are identical, we observed noticeable differences: 1) the transition state ensemble has a well-defined TS region and a late TS for the second step, and 2) larger coordinated protein motions are required to reach the TS of the second step. We have identified key residues (Arg23, Ser117, His118, Lys389), and the Mg2+ ion that contribute in different ways to the reaction coordinate. Accelerated molecular dynamics simulations suggest that the G16P intermediate may reorient without leaving the enzymatic binding pocket, through significant conformational rearrangements of the G16P and of specific loop regions of the human α-PGM.
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Affiliation(s)
- Natércia F Brás
- UCIBIO, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007, Porto, Portugal.,Department of Chemistry and Biochemistry, University of Arizona, 1306 East University Boulevard, Tucson, Arizona, 85721, USA
| | - Pedro A Fernandes
- UCIBIO, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007, Porto, Portugal
| | - Maria J Ramos
- UCIBIO, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007, Porto, Portugal
| | - Steven D Schwartz
- Department of Chemistry and Biochemistry, University of Arizona, 1306 East University Boulevard, Tucson, Arizona, 85721, USA
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Muenks AG, Stiers KM, Beamer LJ. Sequence-structure relationships, expression profiles, and disease-associated mutations in the paralogs of phosphoglucomutase 1. PLoS One 2017; 12:e0183563. [PMID: 28837627 PMCID: PMC5570346 DOI: 10.1371/journal.pone.0183563] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 08/07/2017] [Indexed: 12/11/2022] Open
Abstract
The key metabolic enzyme phosphoglucomutase 1 (PGM1) controls glucose homeostasis in most human cells. Four proteins related to PGM1, known as PGM2, PGM2L1, PGM3 and PGM5, and referred to herein as paralogs, are encoded in the human genome. Although all members of the same enzyme superfamily, these proteins have distinct substrate preferences and different functional roles. The recent association of PGM1 and PGM3 with inherited enzyme deficiencies prompts us to revisit sequence-structure and other relationships among the PGM1 paralogs, which are understudied despite their importance in human biology. Using currently available sequence, structure, and expression data, we investigated evolutionary relationships, tissue-specific expression profiles, and the amino acid preferences of key active site motifs. Phylogenetic analyses indicate both ancient and more recent divergence between the different enzyme sub-groups comprising the human paralogs. Tissue-specific protein and RNA expression profiles show widely varying patterns for each paralog, providing insight into function and disease pathology. Multiple sequence alignments confirm high conservation of key active site regions, but also reveal differences related to substrate specificity. In addition, we find that sequence variants of PGM2, PGM2L1, and PGM5 verified in the human population affect residues associated with disease-related mutants in PGM1 or PGM3. This suggests that inherited diseases related to dysfunction of these paralogs will likely occur in humans.
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Affiliation(s)
- Andrew G Muenks
- Biochemistry Department, University of Missouri, Columbia, Missouri, United States of America
| | - Kyle M Stiers
- Biochemistry Department, University of Missouri, Columbia, Missouri, United States of America
| | - Lesa J Beamer
- Biochemistry Department, University of Missouri, Columbia, Missouri, United States of America
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Stiers KM, Muenks AG, Beamer LJ. Biology, Mechanism, and Structure of Enzymes in the α-d-Phosphohexomutase Superfamily. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2017; 109:265-304. [PMID: 28683921 PMCID: PMC5802415 DOI: 10.1016/bs.apcsb.2017.04.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Enzymes in the α-d-phosphohexomutases superfamily catalyze the reversible conversion of phosphosugars, such as glucose 1-phosphate and glucose 6-phosphate. These reactions are fundamental to primary metabolism across the kingdoms of life and are required for a myriad of cellular processes, ranging from exopolysaccharide production to protein glycosylation. The subject of extensive mechanistic characterization during the latter half of the 20th century, these enzymes have recently benefitted from biophysical characterization, including X-ray crystallography, NMR, and hydrogen-deuterium exchange studies. This work has provided new insights into the unique catalytic mechanism of the superfamily, shed light on the molecular determinants of ligand recognition, and revealed the evolutionary conservation of conformational flexibility. Novel associations with inherited metabolic disease and the pathogenesis of bacterial infections have emerged, spurring renewed interest in the long-appreciated functional roles of these enzymes.
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Affiliation(s)
| | | | - Lesa J Beamer
- University of Missouri, Columbia, MO, United States.
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Stiers KM, Graham AC, Kain BN, Beamer LJ. Asp263 missense variants perturb the active site of human phosphoglucomutase 1. FEBS J 2017; 284:937-947. [PMID: 28117557 DOI: 10.1111/febs.14025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 12/31/2016] [Accepted: 01/19/2017] [Indexed: 11/26/2022]
Abstract
The enzyme phosphoglucomutase 1 (PGM1) plays a central role in glucose homeostasis. Clinical studies have identified mutations in human PGM1 as the cause of PGM1 deficiency, an inherited metabolic disease. One residue, Asp263, has two known variants associated with disease: D263G and D263Y. Biochemical studies have shown that these mutants are soluble and well folded, but have significant catalytic impairment. To better understand this catalytic defect, we determined crystal structures of these two missense variants, both of which reveal a similar and indirect structural change due to the loss of a conserved salt bridge between Asp263 and Arg293. The arginine reorients into the active site, making interactions with residues responsible for substrate binding. Biochemical studies also show that the catalytic phosphoserine of the missense variants is more stable to hydrolysis relative to wild-type enzyme. The structural perturbation resulting from mutation of this single amino acid reveals the molecular mechanism underlying PGM1 deficiency in these missense variants. DATABASE Structural data are available in the PDB under the accession numbers 5JN5 and 5TR2.
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Affiliation(s)
- Kyle M Stiers
- Biochemistry Department, University of Missouri, Columbia, MO, USA
| | - Abigail C Graham
- Biochemistry Department, University of Missouri, Columbia, MO, USA
| | - Bailee N Kain
- Biochemistry Department, University of Missouri, Columbia, MO, USA
| | - Lesa J Beamer
- Biochemistry Department, University of Missouri, Columbia, MO, USA
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Liver glucose metabolism in humans. Biosci Rep 2016; 36:BSR20160385. [PMID: 27707936 PMCID: PMC5293555 DOI: 10.1042/bsr20160385] [Citation(s) in RCA: 233] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 09/19/2016] [Accepted: 10/04/2016] [Indexed: 12/16/2022] Open
Abstract
Information about normal hepatic glucose metabolism may help to understand pathogenic mechanisms underlying obesity and diabetes mellitus. In addition, liver glucose metabolism is involved in glycosylation reactions and connected with fatty acid metabolism. The liver receives dietary carbohydrates directly from the intestine via the portal vein. Glucokinase phosphorylates glucose to glucose 6-phosphate inside the hepatocyte, ensuring that an adequate flow of glucose enters the cell to be metabolized. Glucose 6-phosphate may proceed to several metabolic pathways. During the post-prandial period, most glucose 6-phosphate is used to synthesize glycogen via the formation of glucose 1-phosphate and UDP–glucose. Minor amounts of UDP–glucose are used to form UDP–glucuronate and UDP–galactose, which are donors of monosaccharide units used in glycosylation. A second pathway of glucose 6-phosphate metabolism is the formation of fructose 6-phosphate, which may either start the hexosamine pathway to produce UDP-N-acetylglucosamine or follow the glycolytic pathway to generate pyruvate and then acetyl-CoA. Acetyl-CoA may enter the tricarboxylic acid (TCA) cycle to be oxidized or may be exported to the cytosol to synthesize fatty acids, when excess glucose is present within the hepatocyte. Finally, glucose 6-phosphate may produce NADPH and ribose 5-phosphate through the pentose phosphate pathway. Glucose metabolism supplies intermediates for glycosylation, a post-translational modification of proteins and lipids that modulates their activity. Congenital deficiency of phosphoglucomutase (PGM)-1 and PGM-3 is associated with impaired glycosylation. In addition to metabolize carbohydrates, the liver produces glucose to be used by other tissues, from glycogen breakdown or from de novo synthesis using primarily lactate and alanine (gluconeogenesis).
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