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Farkas P, Fitzpatrick TB. Two pyridoxal phosphate homeostasis proteins are essential for management of the coenzyme pyridoxal 5'-phosphate in Arabidopsis. THE PLANT CELL 2024; 36:3689-3708. [PMID: 38954500 PMCID: PMC11371154 DOI: 10.1093/plcell/koae176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/17/2024] [Accepted: 06/10/2024] [Indexed: 07/04/2024]
Abstract
Coenzyme management is important for homeostasis of the pool of active metabolic enzymes. The coenzyme pyridoxal 5'-phosphate (PLP) is involved in diverse enzyme reactions including amino acid and hormone metabolism. Regulatory proteins that contribute to PLP homeostasis remain to be explored in plants. Here, we demonstrate the importance of proteins annotated as PLP homeostasis proteins (PLPHPs) for controlling PLP in Arabidopsis (Arabidopsis thaliana). A systematic analysis indicates that while most organisms across kingdoms have a single PLPHP homolog, Angiosperms have two. PLPHPs from Arabidopsis bind PLP and exist as monomers, in contrast to reported PLP-dependent enzymes, which exist as multimers. Disrupting the function of both PLPHP homologs perturbs vitamin B6 (pyridoxine) content, inducing a PLP deficit accompanied by light hypersensitive root growth, unlike PLP biosynthesis mutants. Micrografting studies show that the PLP deficit can be relieved distally between shoots and roots. Chemical treatments probing PLP-dependent reactions, notably those for auxin and ethylene, provide evidence that PLPHPs function in the dynamic management of PLP. Assays in vitro show that Arabidopsis PLPHP can coordinate PLP transfer and withdrawal from other enzymes. This study thus expands our knowledge of vitamin B6 biology and highlights the importance of PLP coenzyme homeostasis in plants.
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Affiliation(s)
- Peter Farkas
- Vitamins & Environmental Stress Responses in Plants, Department of Plant Sciences, University of Geneva, 1211 Geneva, Switzerland
| | - Teresa B Fitzpatrick
- Vitamins & Environmental Stress Responses in Plants, Department of Plant Sciences, University of Geneva, 1211 Geneva, Switzerland
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2
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Gougeard N, Sancho-Vaello E, Fernández-Murga ML, Martínez-Sinisterra B, Loukili-Hassani B, Häberle J, Marco-Marín C, Rubio V. Use of pure recombinant human enzymes to assess the disease-causing potential of missense mutations in urea cycle disorders, applied to N-acetylglutamate synthase deficiency. J Inherit Metab Dis 2024. [PMID: 38740568 DOI: 10.1002/jimd.12747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 04/21/2024] [Accepted: 04/23/2024] [Indexed: 05/16/2024]
Abstract
N-acetylglutamate synthase (NAGS) makes acetylglutamate, the essential activator of the first, regulatory enzyme of the urea cycle, carbamoyl phosphate synthetase 1 (CPS1). NAGS deficiency (NAGSD) and CPS1 deficiency (CPS1D) present identical phenotypes. However, they must be distinguished, because NAGSD is cured by substitutive therapy with the N-acetyl-L-glutamate analogue N-carbamyl-L-glutamate, while curative therapy of CPS1D requires liver transplantation. Since their differentiation is done genetically, it is important to ascertain the disease-causing potential of CPS1 and NAGS genetic variants. With this goal, we previously carried out site-directed mutagenesis studies with pure recombinant human CPS1. We could not do the same with human NAGS (HuNAGS) because of enzyme instability, leading to our prior utilization of a bacterial NAGS as an imperfect surrogate of HuNAGS. We now use genuine HuNAGS, stabilized as a chimera of its conserved domain (cHuNAGS) with the maltose binding protein (MBP), and produced in Escherichia coli. MBP-cHuNAGS linker cleavage allowed assessment of the enzymatic properties and thermal stability of cHuNAGS, either wild-type or hosting each one of 23 nonsynonymous single-base changes found in NAGSD patients. For all but one change, disease causation was accounted by the enzymatic alterations identified, including, depending on the variant, loss of arginine activation, increased Km Glutamate, active site inactivation, decreased thermal stability, and protein misfolding. Our present approach outperforms experimental in vitro use of bacterial NAGS or in silico utilization of prediction servers (including AlphaMissense), illustrating with HuNAGS the value for UCDs of using recombinant enzymes for assessing disease-causation and molecular pathogenesis, and for therapeutic guidance.
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Affiliation(s)
- Nadine Gougeard
- Instituto de Biomedicina de Valencia, IBV-CSIC, Valencia, Spain
- Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras, (CIBERER-ISCIII) at the IBV-CSIC, Valencia, Spain
| | | | | | | | | | - Johannes Häberle
- University Children's Hospital Zurich and Children's Research Centre, Zurich, Switzerland
| | - Clara Marco-Marín
- Instituto de Biomedicina de Valencia, IBV-CSIC, Valencia, Spain
- Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras, (CIBERER-ISCIII) at the IBV-CSIC, Valencia, Spain
| | - Vicente Rubio
- Instituto de Biomedicina de Valencia, IBV-CSIC, Valencia, Spain
- Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras, (CIBERER-ISCIII) at the IBV-CSIC, Valencia, Spain
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3
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Ilyin NP, Petersen EV, Kolesnikova TO, Demin KA, Khatsko SL, Apuhtin KV, Kalueff AV. Developing Peripheral Biochemical Biomarkers of Brain Disorders: Insights from Zebrafish Models. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:377-391. [PMID: 38622104 DOI: 10.1134/s0006297924020160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 01/09/2024] [Accepted: 02/13/2024] [Indexed: 04/17/2024]
Abstract
High prevalence of human brain disorders necessitates development of the reliable peripheral biomarkers as diagnostic and disease-monitoring tools. In addition to clinical studies, animal models markedly advance studying of non-brain abnormalities associated with brain pathogenesis. The zebrafish (Danio rerio) is becoming increasingly popular as an animal model organism in translational neuroscience. These fish share some practical advantages over mammalian models together with high genetic homology and evolutionarily conserved biochemical and neurobehavioral phenotypes, thus enabling large-scale modeling of human brain diseases. Here, we review mounting evidence on peripheral biomarkers of brain disorders in zebrafish models, focusing on altered biochemistry (lipids, carbohydrates, proteins, and other non-signal molecules, as well as metabolic reactions and activity of enzymes). Collectively, these data strongly support the utility of zebrafish (from a systems biology standpoint) to study peripheral manifestations of brain disorders, as well as highlight potential applications of biochemical biomarkers in zebrafish models to biomarker-based drug discovery and development.
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Affiliation(s)
- Nikita P Ilyin
- Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, 199034, Russia.
| | - Elena V Petersen
- Moscow Institute of Physics and Technology, Moscow, 115184, Russia.
| | - Tatyana O Kolesnikova
- Neuroscience Program, Sirius University of Science and Technology, Sochi, 354340, Russia.
| | - Konstantin A Demin
- Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, 199034, Russia.
- Moscow Institute of Physics and Technology, Moscow, 115184, Russia
- Institute of Experimental Medicine, Almazov National Medical Research Centre, Ministry of Healthcare of the Russian Federation, St. Petersburg, 197341, Russia
- Laboratory of Preclinical Bioscreening, Granov Russian Research Center of Radiology and Surgical Technologies, Ministry of Healthcare of the Russian Federation, Pesochny, 197758, Russia
| | | | - Kirill V Apuhtin
- Laboratory of Biopsychiatry, Scientific Research Institute of Neurosciences and Medicine, Novosibirsk, 630117, Russia.
- Neuroscience Division, Sirius University of Science and Technology, Sirius Federal Territory, 354340, Russia
| | - Allan V Kalueff
- Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, 199034, Russia.
- Institute of Experimental Medicine, Almazov National Medical Research Centre, Ministry of Healthcare of the Russian Federation, St. Petersburg, 197341, Russia
- Ural Federal University, Ekaterinburg, 620002, Russia
- Laboratory of Biopsychiatry, Scientific Research Institute of Neurosciences and Medicine, Novosibirsk, 630117, Russia
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4
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Gil-Martínez J, Bernardo-Seisdedos G, Mato JM, Millet O. The use of pharmacological chaperones in rare diseases caused by reduced protein stability. Proteomics 2022; 22:e2200222. [PMID: 36205620 DOI: 10.1002/pmic.202200222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/26/2022] [Accepted: 09/29/2022] [Indexed: 11/05/2022]
Abstract
Rare diseases are most often caused by inherited genetic disorders that, after translation, will result in a protein with altered function. Decreased protein stability is the most frequent mechanism associated with a congenital pathogenic missense mutation and it implies the destabilization of the folded conformation in favour of unfolded or misfolded states. In the cellular context and when experimental data is available, a mutant protein with altered thermodynamic stability often also results in impaired homeostasis, with the deleterious accumulation of protein aggregates, metabolites and/or metabolic by-products. In the last decades, a significant effort has enabled the characterization of rare diseases associated to protein stability defects and triggered the development of innovative therapeutic intervention lines, say, the use of pharmacological chaperones to correct the intracellular impaired homeostasis. Here, we review the current knowledge on rare diseases caused by reduced protein stability, paying special attention to the thermodynamic aspects of the protein destabilization, also focusing on some examples where pharmacological chaperones are being tested.
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Affiliation(s)
- Jon Gil-Martínez
- Precision Medicine and Metabolism Laboratory, CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia, Spain
| | | | - José M Mato
- Precision Medicine and Metabolism Laboratory, CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
| | - Oscar Millet
- Precision Medicine and Metabolism Laboratory, CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia, Spain.,ATLAS Molecular Pharma, Bizkaia, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
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5
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Tramonti A, Ghatge MS, Babor JT, Musayev FN, di Salvo ML, Barile A, Colotti G, Giorgi A, Paredes SD, Donkor AK, Al Mughram MH, de Crécy‐Lagard V, Safo MK, Contestabile R. Characterization of the Escherichia coli pyridoxal 5'-phosphate homeostasis protein (YggS): Role of lysine residues in PLP binding and protein stability. Protein Sci 2022; 31:e4471. [PMID: 36218140 PMCID: PMC9601805 DOI: 10.1002/pro.4471] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/04/2022] [Accepted: 07/25/2022] [Indexed: 02/04/2023]
Abstract
The pyridoxal 5'-phosphate (PLP) homeostasis protein (PLPHP) is a ubiquitous member of the COG0325 family with apparently no catalytic activity. Although the actual cellular role of this protein is unknown, it has been observed that mutations of the PLPHP encoding gene affect the activity of PLP-dependent enzymes, B6 vitamers and amino acid levels. Here we report a detailed characterization of the Escherichia coli ortholog of PLPHP (YggS) with respect to its PLP binding and transfer properties, stability, and structure. YggS binds PLP very tightly and is able to slowly transfer it to a model PLP-dependent enzyme, serine hydroxymethyltransferase. PLP binding to YggS elicits a conformational/flexibility change in the protein structure that is detectable in solution but not in crystals. We serendipitously discovered that the K36A variant of YggS, affecting the lysine residue that binds PLP at the active site, is able to bind PLP covalently. This observation led us to recognize that a number of lysine residues, located at the entrance of the active site, can replace Lys36 in its PLP binding role. These lysines form a cluster of charged residues that affect protein stability and conformation, playing an important role in PLP binding and possibly in YggS function.
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Affiliation(s)
- Angela Tramonti
- Istituto di Biologia e Patologia MolecolariConsiglio Nazionale delle RicercheRomeItaly
- Istituto Pasteur Italia‐Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Mohini S. Ghatge
- Institute for Structural Biology, Drug Discovery and Development, Department of Medicinal ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Jill T. Babor
- Department of Microbiology and Cell ScienceUniversity of FloridaGainsvilleFloridaUSA
| | - Faik N. Musayev
- Institute for Structural Biology, Drug Discovery and Development, Department of Medicinal ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Martino Luigi di Salvo
- Istituto Pasteur Italia‐Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Anna Barile
- Istituto di Biologia e Patologia MolecolariConsiglio Nazionale delle RicercheRomeItaly
- Istituto Pasteur Italia‐Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Gianni Colotti
- Istituto di Biologia e Patologia MolecolariConsiglio Nazionale delle RicercheRomeItaly
| | - Alessandra Giorgi
- Istituto Pasteur Italia‐Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Steven D. Paredes
- Institute for Structural Biology, Drug Discovery and Development, Department of Medicinal ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Akua K. Donkor
- Institute for Structural Biology, Drug Discovery and Development, Department of Medicinal ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Mohammed H. Al Mughram
- Institute for Structural Biology, Drug Discovery and Development, Department of Medicinal ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Valérie de Crécy‐Lagard
- Department of Microbiology and Cell ScienceUniversity of FloridaGainsvilleFloridaUSA
- Genetics InstituteUniversity of FloridaGainesvilleFloridaUSA
| | - Martin K. Safo
- Institute for Structural Biology, Drug Discovery and Development, Department of Medicinal ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Roberto Contestabile
- Istituto Pasteur Italia‐Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
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6
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The Conserved Family of the Pyridoxal Phosphate-Binding Protein (PLPBP) and Its Cyanobacterial Paradigm PipY. Life (Basel) 2022; 12:life12101622. [PMID: 36295057 PMCID: PMC9605639 DOI: 10.3390/life12101622] [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: 09/20/2022] [Revised: 10/05/2022] [Accepted: 10/15/2022] [Indexed: 11/16/2022] Open
Abstract
The PLPBP family of pyridoxal phosphate-binding proteins has a high degree of sequence conservation and is represented in all three domains of life. PLPBP members, of which a few representatives have been studied in different contexts, are single-domain proteins with no known enzymatic activity that exhibit the fold type III of PLP-holoenzymes, consisting in an α/β barrel (TIM-barrel), where the PLP cofactor is solvent-exposed. Despite the constant presence of cofactor PLP (a key catalytic element in PLP enzymes), PLPBP family members appear to have purely regulatory functions affecting the homeostasis of vitamin B6 vitamers and amino/keto acids. Perturbation of these metabolites and pleiotropic phenotypes have been reported in bacteria and zebrafish after PLPBP gene inactivation as well as in patients with vitamin B6-dependent epilepsy that results from loss-of-function mutations at the PLPBP. Here, we review information gathered from diverse studies and biological systems, emphasizing the structural and functional conservation of the PLPBP members and discussing the informative nature of model systems and experimental approaches. In this context, the relatively high level of structural and functional characterization of PipY from Synechococcus elongatus PCC 7942 provides a unique opportunity to investigate the PLPBP roles in the context of a signaling pathway conserved in cyanobacteria.
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7
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Abstract
The brain is a highly energy-demanding organ and requires bioenergetic adaptability to balance normal activity with pathophysiological fuelling of spontaneous recurrent seizures, the hallmark feature of the epilepsies. Recurrent or prolonged seizures have long been known to permanently alter neuronal circuitry and to cause excitotoxic injury and aberrant inflammation. Furthermore, pathological changes in bioenergetics and metabolism are considered downstream consequences of epileptic seizures that begin at the synaptic level. However, as we highlight in this Review, evidence is also emerging that primary derangements in cellular or mitochondrial metabolism can result in seizure genesis and lead to spontaneous recurrent seizures. Basic and translational research indicates that the relationships between brain metabolism and epileptic seizures are complex and bidirectional, producing a vicious cycle that compounds the deleterious consequences of seizures. Metabolism-based treatments such as the high-fat, antiseizure ketogenic diet have become mainstream, and metabolic substrates and enzymes have become attractive molecular targets for seizure prevention and recovery. Moreover, given that metabolism is crucial for epigenetic as well as inflammatory changes, the idea that epileptogenesis can be both negatively and positively influenced by metabolic changes is rapidly gaining ground. Here, we review evidence that supports both pathophysiological and therapeutic roles for brain metabolism in epilepsy.
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8
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Mechanism of pyridoxine 5'-phosphate accumulation in PLPBP protein-deficiency. J Bacteriol 2022; 204:e0052121. [PMID: 34978460 DOI: 10.1128/jb.00521-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The pyridoxal 5'-phosphate (PLP)-binding protein (PLPBP) plays an important role in vitamin B6 homeostasis. Loss of this protein in organisms such as Escherichia coli and humans disrupts the vitamin B6 pool and induces intracellular accumulation of pyridoxine 5'-phosphate (PNP), which is normally undetectable in wild-type cells. The accumulated PNP could affect diverse metabolic systems through inhibition of some PLP-dependent enzymes. In this study, we investigated the as yet unclear mechanism of intracellular accumulation of PNP by the loss of PLPBP protein encoded by yggS in E. coli. Genetic studies using several PLPBP-deficient strains of E. coli lacking known enzyme(s) in the de novo or salvage pathway of vitamin B6, which includes pyridoxine (amine) 5'-phosphate oxidase (PNPO), PNP synthase, pyridoxal kinase, and pyridoxal reductase, demonstrated that neither the flux from the de novo pathway nor the salvage pathway solely contributed to the PNP accumulation caused by the PLPBP mutation. Studies with the strains lacking both PLPBP and PNPO suggested that PNP shares the same pool with PMP, and showed that PNP levels are impacted by PMP levels and vice versa. We show that disruption of PLPBP lead to perturb PMP homeostasis, which may result in PNP accumulation in the PLPBP-deficient strains. Importance A PLP-binding protein PLPBP from the conserved COG0325 family has recently been recognized as a key player in vitamin B6 homeostasis in various organisms. Loss of PLPBP disrupts vitamin B6 homeostasis and perturbs diverse metabolisms, including amino acid and α-keto acid metabolism. Accumulation of PNP is a characteristic phenotype of the PLPBP deficiency and is suggested to be a potential cause of the pleiotropic effects, but the mechanism of the PNP accumulation was poorly understood. In this study, we show that fluxes for PNP synthesis/metabolism are not responsible for the accumulation of PNP. Our results indicate that PLPBP is involved in the homeostasis of pyridoxamine 5'-phosphate, and its disruption may lead to the accumulation of PNP in PLPBP-deficiency.
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9
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Abstract
Inborn errors of metabolism have been considered as an infrequent cause of epilepsy. Improvement in diagnostics has improved the detection of a metabolic basis of recurrent seizures in neonates and children. The term 'metabolic epilepsy' is used to suggest inherited metabolic disorders with predominant epileptic manifestations as well as those where epilepsy is part of the overall neurological phenotype. Several of these disorders are treatable, and the physician should bear in mind the classical ages of presentation. As there are no specific clinical or electrographic features suggestive of metabolic epilepsies, an early suspicion is based on clinical and laboratory clues. Fortunately, with the advancement of gene sequencing technology, a diagnosis of these rare conditions is more straightforward and may not require invasive procedures such as biopsies, multiple metabolic stress-induced testing for abnormalities, and cerebrospinal fluid analysis. A gene panel may suffice in most cases and can be done from a blood sample. In many countries, many treatable metabolic disorders are now part of the neonatal screen. Early diagnosis and treatment of these disorders can result in the prevention of a full-scale metabolic crisis and improvement of neurological outcomes. Long-term neurological outcomes are variable and additional therapies may be required.
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10
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Vu HN, Downs DM. Loss of YggS (COG0325) impacts aspartate metabolism in Salmonella enterica. Mol Microbiol 2021; 116:1232-1240. [PMID: 34498310 DOI: 10.1111/mmi.14810] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/24/2021] [Accepted: 09/07/2021] [Indexed: 12/01/2022]
Abstract
YggS is a pyridoxal 5'-phosphate (PLP)-binding protein of the conserved COG0325 family. Despite a connection with vitamin B6 homeostasis in many species, neither a precise biochemical activity nor the molecular mechanism of how YggS contributes to cellular function has been described. In a transposon mutagenesis screen, we found that insertions in aspC (encoding a PLP-dependent aspartate aminotransferase, EC 2.6.1.1) in a Salmonella enterica strain lacking yggS caused a synthetic growth defect, which could be rescued by the addition of exogenous aspartate. Characterization of spontaneous suppressors which improved the growth of the yggS aspC double mutant suggested that this synthetic aspartate limitation was dependent on TyrB, a PLP-dependent aromatic amino acid aminotransferase (EC 2.6.1.57). Genetic and biochemical data were consistent with the hypothesis that TyrB activity was inhibited by accumulated pyridoxine 5'-phosphate and α-keto acids caused by a yggS mutation. This study provides data consistent with a working model implicating YggS in modulating concentrations of B6 vitamers via transamination.
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Affiliation(s)
- Huong N Vu
- Department of Microbiology, The University of Georgia, Athens, Georgia, USA
| | - Diana M Downs
- Department of Microbiology, The University of Georgia, Athens, Georgia, USA
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11
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Heath O, Pitt J, Mandelstam S, Kuschel C, Vasudevan A, Donoghue S. Early-onset vitamin B 6-dependent epilepsy due to pathogenic PLPBP variants in a premature infant: A case report and review of the literature. JIMD Rep 2021; 58:3-11. [PMID: 33728241 PMCID: PMC7932866 DOI: 10.1002/jmd2.12183] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/26/2020] [Accepted: 10/29/2020] [Indexed: 01/17/2023] Open
Abstract
Vitamin B6-dependent epilepsies are a heterogeneous group of disorders characterized by decreased availability of the active cofactor pyridoxal-5'-phosphate (PLP). While pathogenic variants in ALDH7A1 or PNPO genes account for most cases of these disorders, biallelic pathogenic variants in PLPBP have been shown to cause a form of early onset vitamin B6-dependent epilepsy (EPVB6D). PLPBP is thought to play a role in the homeostatic regulation of vitamin B6, by supplying PLP to apoenzymes while limiting side-reaction toxicity related to excess unbound PLP. Neonatal-onset intractable seizures that respond to pyridoxine and/or PLP are a predominant feature of EPVB6D in humans. Unlike other causes of vitamin B6-dependent epilepsies; however, a specific biomarker for this disorder has yet to be identified. Here we present data from a premature infant found to have pathogenic variants in PLPBP and propose that prematurity may provide an additional clue for early consideration of this diagnosis. We discuss these findings in context of previously published genotypic, phenotypic, and metabolic data from similarly affected patients.
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Affiliation(s)
- Oliver Heath
- Department of Metabolic MedicineThe Royal Children's HospitalMelbourneAustralia
| | - James Pitt
- Department of Biochemical Genetics, Victorian Clinical Genetics ServiceMurdoch Children's Research InstituteMelbourneAustralia
- Department of PaediatricsUniversity of MelbourneMelbourneAustralia
| | - Simone Mandelstam
- Department of Medical ImagingThe Royal Children's Hospital and Murdoch Children's Research InstituteMelbourneAustralia
- Department of PaediatricsUniversity of MelbourneMelbourneAustralia
- Department of RadiologyUniversity of MelbourneMelbourneAustralia
| | - Carl Kuschel
- Department of Obstetrics and GynecologyThe Royal Women's HospitalMelbourneAustralia
| | - Anand Vasudevan
- Department of GeneticsThe Royal Women's HospitalMelbourneAustralia
| | - Sarah Donoghue
- Department of Metabolic MedicineThe Royal Children's HospitalMelbourneAustralia
- Department of Biochemical Genetics, Victorian Clinical Genetics ServiceMurdoch Children's Research InstituteMelbourneAustralia
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12
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LeVine SM, Tsau S. Substrate Reduction Therapy for Krabbe Disease: Exploring the Repurposing of the Antibiotic D-Cycloserine. Front Pediatr 2021; 9:807973. [PMID: 35118033 PMCID: PMC8804370 DOI: 10.3389/fped.2021.807973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/24/2021] [Indexed: 01/10/2023] Open
Abstract
Krabbe disease is a lysosomal storage disease that is caused by a deficiency in galactosylceramidase. Infantile onset disease is the most common presentation, which includes progressive neurological deterioration with corresponding demyelination, development of globoid cells, astrocyte gliosis, etc. Hemopoietic stem cell transplantation (HSCT) is a disease modifying therapy, but this intervention is insufficient with many patients still experiencing developmental delays and progressive deterioration. Preclinical studies have used animal models, e.g., twitcher mice, to test different experimental therapies resulting in developments that have led to progressive improvements in the therapeutic impact. Some recent advances have been in the areas of gene therapy and substrate reduction therapy (SRT), as well as using these in combination with HSCT. Unfortunately, new experimental approaches have encountered obstacles which have impeded the translation of novel therapies to human patients. In an effort to identify a safe adjunct therapy, D-cycloserine was tested in preliminary studies in twitcher mice. When administered as a standalone therapy, D-cycloserine was shown to lengthen the lifespan of twitcher mice in a small but significant manner. D-Cycloserine is an FDA approved antibiotic used for drug resistant tuberculosis. It also acts as a partial agonist of the NMDA receptor, which has led to numerous human studies for a range of neuropsychiatric and neurological conditions. In addition, D-cycloserine may inhibit serine palmitoyltransferase (SPT), which catalyzes the rate-limiting step in sphingolipid production. The enantiomer, L-cycloserine, is a much more potent inhibitor of SPT than D-cycloserine. Previously, L-cycloserine was found to act as an effective SRT agent in twitcher mice as both a standalone therapy and as part of combination therapies. L-Cycloserine is not approved for human use, and its potent inhibitory properties may limit its ability to maintain a level of partial inactivation of SPT that is also safe. In theory, D-cycloserine would encompass a much broader dosage range to achieve a safe degree of partial inhibition of SPT, which increases the likelihood it could advance to human studies in patients with Krabbe disease. Furthermore, additional properties of D-cycloserine raise the possibility of other therapeutic mechanisms that could be exploited for the treatment of this disease.
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Affiliation(s)
- Steven M LeVine
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Sheila Tsau
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, United States
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13
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The Role of YggS in Vitamin B 6 Homeostasis in Salmonella enterica Is Informed by Heterologous Expression of Yeast SNZ3. J Bacteriol 2020; 202:JB.00383-20. [PMID: 32900833 DOI: 10.1128/jb.00383-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/28/2020] [Indexed: 11/20/2022] Open
Abstract
YggS (COG0325) is a pyridoxal 5'-phosphate (PLP)-binding protein proposed to be involved in homeostasis of B6 vitamers. In Salmonella enterica, lack of yggS resulted in phenotypes that were distinct and others that were similar to those of a yggS mutant of Escherichia coli Like other organisms, yggS mutants of S. enterica accumulate endogenous pyridoxine 5'-phosphate (PNP). Data herein show that strains lacking YggS accumulated ∼10-fold more PLP in growth medium than a parental strain. The deoxyxylulose 5-phosphate-dependent biosynthetic pathway for PLP and the PNP/pyridoxamine 5'-phosphate (PMP) oxidase credited with interconverting B6 vitamers were replaced with a single PLP synthase from Saccharomyces cerevisiae The impact of a yggS deletion on the intracellular and extracellular levels of B6 vitamers in this restructured strain supported a role for PdxH in PLP homeostasis and led to a general model for YggS function in PLP-PMP cycling. Our findings uncovered broader consequences of a yggS mutation than previously reported and suggest that the accumulation of PNP is not a direct effect of lacking YggS but rather a downstream consequence.IMPORTANCE Pyridoxal 5'-phosphate (PLP) is an essential cofactor for enzymes in all domains of life. Perturbations in PLP or B6 vitamer content can be detrimental, notably causing B6-dependent epilepsy in humans. YggS homologs are broadly conserved and have been implicated in altered levels of B6 vitamers in multiple organisms. The biochemical activity of YggS, expected to be conserved across domains, is not yet known. Herein, a simplified heterologous pathway minimized metabolic variables and allowed the dissection of this system to generate new metabolic knowledge that will be relevant to understanding YggS.
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14
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Labella JI, Cantos R, Salinas P, Espinosa J, Contreras A. Distinctive Features of PipX, a Unique Signaling Protein of Cyanobacteria. Life (Basel) 2020; 10:life10060079. [PMID: 32481703 PMCID: PMC7344720 DOI: 10.3390/life10060079] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 05/23/2020] [Accepted: 05/26/2020] [Indexed: 12/20/2022] Open
Abstract
PipX is a unique cyanobacterial protein identified by its ability to bind to PII and NtcA, two key regulators involved in the integration of signals of the nitrogen/carbon and energy status, with a tremendous impact on nitrogen assimilation and gene expression in cyanobacteria. PipX provides a mechanistic link between PII, the most widely distributed signaling protein, and NtcA, a global transcriptional regulator of cyanobacteria. PII, required for cell survival unless PipX is inactivated or down-regulated, functions by protein–protein interactions with transcriptional regulators, transporters, and enzymes. In addition, PipX appears to be involved in a wider signaling network, supported by the following observations: (i) PII–PipX complexes interact with PlmA, an as yet poorly characterized transcriptional regulator also restricted to cyanobacteria; (ii) the pipX gene is functionally connected with pipY, a gene encoding a universally conserved pyridoxal phosphate binding protein (PLPBP) involved in vitamin B6 and amino acid homeostasis, whose loss-of-function mutations cause B6-dependent epilepsy in humans, and (iii) pipX is part of a relatively robust, six-node synteny network that includes pipY and four additional genes that might also be functionally connected with pipX. In this overview, we propose that the study of the protein–protein interaction and synteny networks involving PipX would contribute to understanding the peculiarities and idiosyncrasy of signaling pathways that are conserved in cyanobacteria.
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15
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Abstract
The pyridoxal 5'-phosphate-binding protein (PLPBP) is an evolutionarily conserved protein linked to pyridoxal 5'-phosphate-binding. Although mutations in PLPBP were shown to cause vitamin B6-dependent epilepsy, its cellular role and function remain elusive. We here report a detailed biochemical investigation of human PLPBP and its epilepsy-causing mutants by evaluating stability, cofactor binding, and oligomerization. In this context, chemical cross-linking combined with mass spectrometry unraveled an unexpected dimeric assembly of PLPBP. Furthermore, the interaction network of PLPBP was elucidated by chemical cross-linking paired with co-immunoprecipitation. A mass spectrometric analysis in a PLPBP knockout cell line resulted in distinct proteomic changes compared to wild type cells, including upregulation of several cytoskeleton- and cell division-associated proteins. Finally, transfection experiments with vitamin B6-dependent epilepsy-causing PLPBP variants indicate a potential role of PLPBP in cell division as well as proper muscle function. Taken together, our studies on the structure and cellular role of human PLPBP enable a better understanding of the physiological and pathological mechanism of this important protein.
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Affiliation(s)
- Anja Fux
- Department
of Chemistry, Chair of Organic Chemistry II, Center for Integrated
Protein Science (CIPSM), Technische Universität
München, Lichtenbergstraße 4, 85748 Garching, Germany
| | - Stephan A. Sieber
- Department
of Chemistry, Chair of Organic Chemistry II, Center for Integrated
Protein Science (CIPSM), Technische Universität
München, Lichtenbergstraße 4, 85748 Garching, Germany
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16
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Johnstone DL, Al-Shekaili HH, Tarailo-Graovac M, Wolf NI, Ivy AS, Demarest S, Roussel Y, Ciapaite J, van Roermund CWT, Kernohan KD, Kosuta C, Ban K, Ito Y, McBride S, Al-Thihli K, Abdelrahim RA, Koul R, Al Futaisi A, Haaxma CA, Olson H, Sigurdardottir LY, Arnold GL, Gerkes EH, Boon M, Heiner-Fokkema MR, Noble S, Bosma M, Jans J, Koolen DA, Kamsteeg EJ, Drögemöller B, Ross CJ, Majewski J, Cho MT, Begtrup A, Wasserman WW, Bui T, Brimble E, Violante S, Houten SM, Wevers RA, van Faassen M, Kema IP, Lepage N, Lines MA, Dyment DA, Wanders RJA, Verhoeven-Duif N, Ekker M, Boycott KM, Friedman JM, Pena IA, van Karnebeek CDM. PLPHP deficiency: clinical, genetic, biochemical, and mechanistic insights. Brain 2020; 142:542-559. [PMID: 30668673 DOI: 10.1093/brain/awy346] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 10/30/2018] [Accepted: 11/13/2018] [Indexed: 12/20/2022] Open
Abstract
Biallelic pathogenic variants in PLPBP (formerly called PROSC) have recently been shown to cause a novel form of vitamin B6-dependent epilepsy, the pathophysiological basis of which is poorly understood. When left untreated, the disease can progress to status epilepticus and death in infancy. Here we present 12 previously undescribed patients and six novel pathogenic variants in PLPBP. Suspected clinical diagnoses prior to identification of PLPBP variants included mitochondrial encephalopathy (two patients), folinic acid-responsive epilepsy (one patient) and a movement disorder compatible with AADC deficiency (one patient). The encoded protein, PLPHP is believed to be crucial for B6 homeostasis. We modelled the pathogenicity of the variants and developed a clinical severity scoring system. The most severe phenotypes were associated with variants leading to loss of function of PLPBP or significantly affecting protein stability/PLP-binding. To explore the pathophysiology of this disease further, we developed the first zebrafish model of PLPHP deficiency using CRISPR/Cas9. Our model recapitulates the disease, with plpbp-/- larvae showing behavioural, biochemical, and electrophysiological signs of seizure activity by 10 days post-fertilization and early death by 16 days post-fertilization. Treatment with pyridoxine significantly improved the epileptic phenotype and extended lifespan in plpbp-/- animals. Larvae had disruptions in amino acid metabolism as well as GABA and catecholamine biosynthesis, indicating impairment of PLP-dependent enzymatic activities. Using mass spectrometry, we observed significant B6 vitamer level changes in plpbp-/- zebrafish, patient fibroblasts and PLPHP-deficient HEK293 cells. Additional studies in human cells and yeast provide the first empirical evidence that PLPHP is localized in mitochondria and may play a role in mitochondrial metabolism. These models provide new insights into disease mechanisms and can serve as a platform for drug discovery.
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Affiliation(s)
- Devon L Johnstone
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Hilal H Al-Shekaili
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.,British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Maja Tarailo-Graovac
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.,British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada.,Institute of Physiology and Biochemistry, Faculty of Biology, The University of Belgrade, Belgrade, Serbia.,Departments of Biochemistry, Molecular Biology, and Medical Genetics, Cumming School of Medicine, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Nicole I Wolf
- Department of Child Neurology, Amsterdam University Medical Centres, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Autumn S Ivy
- Division of Child Neurology, Department of Neurology and Neurological Sciences, Stanford University School of Medicine, CA, USA
| | - Scott Demarest
- Departments of Pediatrics and Neurology, University of Colorado School of Medicine, Children's Hospital Colorado, CO, USA
| | - Yann Roussel
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Jolita Ciapaite
- Department of Genetics, Center for Molecular Medicine, University Medical Center, Utrecht, The Netherlands
| | - Carlo W T van Roermund
- Department of Pediatrics and Clinical Chemistry, Laboratory Division, Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Kristin D Kernohan
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Ceres Kosuta
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Kevin Ban
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Yoko Ito
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Skye McBride
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Khalid Al-Thihli
- Genetic and Developmental Medicine Clinic, Sultan Qaboos University Hospital, Muscat, Oman
| | - Rana A Abdelrahim
- Department of Child Health, Sultan Qaboos University Hospital, Muscat, Oman
| | - Roshan Koul
- Paediatric Neurology Unit, Child Health Department, Sultan Qaboos University Hospital, Muscat, Oman
| | - Amna Al Futaisi
- Paediatric Neurology Unit, Child Health Department, Sultan Qaboos University Hospital, Muscat, Oman
| | - Charlotte A Haaxma
- Department of Pediatric Neurology, Amalia Children's Hospital and Donders Institute of Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Heather Olson
- Department of Neurology, Division of Epilepsy and Clinical Neurophysiology, Boston Children's Hospital, Boston, MA, USA
| | - Laufey Yr Sigurdardottir
- Department of Neurology, University of Central Florida, Nemours Children's Hospital, Orlando, FL, USA
| | - Georgianne L Arnold
- Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburg, PA, USA
| | - Erica H Gerkes
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - M Boon
- Department of Neurology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - M Rebecca Heiner-Fokkema
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Sandra Noble
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Marjolein Bosma
- Department of Genetics, Center for Molecular Medicine, University Medical Center, Utrecht, The Netherlands
| | - Judith Jans
- Department of Genetics, Center for Molecular Medicine, University Medical Center, Utrecht, The Netherlands.,United for Metabolic Diseases, The Netherlands
| | - David A Koolen
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Britt Drögemöller
- British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada.,Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Colin J Ross
- British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada.,Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Jacek Majewski
- McGill University and Genome Quebec Innovation Centre, Montreal, QC, Canada.,Department of Human Genetics, McGill University, Montreal, QC, Canada
| | | | | | - Wyeth W Wasserman
- British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Tuan Bui
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Elise Brimble
- Department of Neurology and Neurological Sciences, Stanford Medicine, Stanford, CA, USA
| | - Sara Violante
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Sander M Houten
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ron A Wevers
- United for Metabolic Diseases, The Netherlands.,Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Martijn van Faassen
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Ido P Kema
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Nathalie Lepage
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | | | - Matthew A Lines
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Division of Metabolics and Newborn Screening, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - David A Dyment
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Medical Genetics, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - Ronald J A Wanders
- Department of Pediatrics and Clinical Chemistry, Laboratory Division, Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centres, Amsterdam, The Netherlands.,United for Metabolic Diseases, The Netherlands
| | - Nanda Verhoeven-Duif
- Department of Genetics, Center for Molecular Medicine, University Medical Center, Utrecht, The Netherlands.,United for Metabolic Diseases, The Netherlands
| | - Marc Ekker
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Kym M Boycott
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Medical Genetics, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - Jan M Friedman
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.,British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Izabella A Pena
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Clara D M van Karnebeek
- British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada.,United for Metabolic Diseases, The Netherlands.,Departments of Pediatrics and Clinical Genetics, Amsterdam University Medical Centres, Amsterdam, The Netherlands.,Centre for Molecular Medicine and Therapeutics, Department of Pediatrics, University of British Columbia, Vancouver, Canada
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17
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Ito T, Hori R, Hemmi H, Downs DM, Yoshimura T. Inhibition of glycine cleavage system by pyridoxine 5'-phosphate causes synthetic lethality in glyA yggS and serA yggS in Escherichia coli. Mol Microbiol 2019; 113:270-284. [PMID: 31677193 DOI: 10.1111/mmi.14415] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2019] [Indexed: 12/15/2022]
Abstract
The YggS/Ybl036c/PLPBP family includes conserved pyridoxal 5'-phosphate (PLP)-binding proteins that play a critical role in the homeostasis of vitamin B6 and amino acids. Disruption of members of this family causes pleiotropic effects in many organisms by unknown mechanisms. In Escherichia coli, conditional lethality of the yggS and glyA (encoding serine hydroxymethyltransferase) has been described, but the mechanism of lethality was not determined. Strains lacking yggS and serA (3-phosphoglycerate dehydrogenase) were conditionally lethality in the M9-glucose medium supplemented with Gly. Analyses of vitamin B6 pools found the high-levels of pyridoxine 5'-phosphate (PNP) in the two yggS mutants. Growth defects of the double mutants could be eliminated by overexpressing PNP/PMP oxidase (PdxH) to decrease the PNP levels. Further, a serA pdxH strain, which accumulates PNP in the presence of yggS, exhibited similar phenotype to serA yggS mutant. Together these data suggested the inhibition of the glycine cleavage (GCV) system caused the synthetic lethality. Biochemical assays confirmed that PNP disrupts the GCV system by competing with PLP in GcvP protein. Our data are consistent with a model in which PNP-dependent inhibition of the GCV system causes the conditional lethality observed in the glyA yggS or serA yggS mutants.
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Affiliation(s)
- Tomokazu Ito
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi, 464-8601, Japan
| | - Ran Hori
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi, 464-8601, Japan
| | - Hisashi Hemmi
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi, 464-8601, Japan
| | - Diana M Downs
- Department of Microbiology, University of Georgia, Athens, GA, 30602, USA
| | - Tohru Yoshimura
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi, 464-8601, Japan
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18
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Shi L, Liu L, Ma Z, Lv X, Li C, Xu L, Han B, Li Y, Zhao F, Yang Y, Sun D. Identification of genetic associations of ECHS1 gene with milk fatty acid traits in dairy cattle. Anim Genet 2019; 50:430-438. [PMID: 31392738 DOI: 10.1111/age.12833] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2019] [Indexed: 12/20/2022]
Abstract
Our previous genome-wide association study identified 83 genome-wide significant SNPs and 20 novel promising candidate genes for milk fatty acids in Chinese Holstein. Among them, the enoyl-CoA hydratase, short chain 1 (ECHS1) and enoyl-CoA hydratase and 3-hydroxyacyl CoA dehydrogenase (EHHADH) genes were located near two SNPs and one SNP respectively, and they play important roles in fatty acid metabolism pathways. We herein validated whether the two genes have genetic effects on milk fatty acid traits in dairy cattle. By re-sequencing the full-length coding region, partially adjacent introns and 3000 bp up/downstream flanking sequences, we identified 12 SNPs in ECHS1: two in exons, four in the 3' flanking region and six in introns. The g.25858322C>T SNP results in an amino acid replacement from leucine to phenylalanine and changes the secondary structure of the ECHS1 protein, and single-locus association analysis showed that it was significantly associated with three milk fatty acids (P = 0.0002-0.0013). The remaining 11 SNPs were found to be significantly associated with at least one milk fatty acid (P = <0.0001-0.0040). Also, we found that two haplotype blocks, consisting of nine and two SNPs respectively, were significantly associated with eight milk fatty acids (P = <0.0001-0.0125). However, none of polymorphisms was observed in the EHHADH gene. In conclusion, our findings are the first to indicate that the ECHS1 gene has a significant genetic impact on long-chain unsaturated and medium-chain saturated fatty acid traits in dairy cattle, although the biological mechanism is still undetermined and requires further in-depth validation.
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Affiliation(s)
- L Shi
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, National Engineering Laboratory for Animal Breeding, China Agricultural University, Beijing, 100193, China
| | - L Liu
- Beijing Dairy Cattle Center, Beijing, 100192, China
| | - Z Ma
- Beijing Dairy Cattle Center, Beijing, 100192, China
| | - X Lv
- Beijing Dairy Cattle Center, Beijing, 100192, China
| | - C Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, National Engineering Laboratory for Animal Breeding, China Agricultural University, Beijing, 100193, China
| | - L Xu
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, National Engineering Laboratory for Animal Breeding, China Agricultural University, Beijing, 100193, China
| | - B Han
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, National Engineering Laboratory for Animal Breeding, China Agricultural University, Beijing, 100193, China
| | - Y Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, National Engineering Laboratory for Animal Breeding, China Agricultural University, Beijing, 100193, China.,Beijing Dairy Cattle Center, Beijing, 100192, China
| | - F Zhao
- Beijing Dairy Cattle Center, Beijing, 100192, China
| | - Y Yang
- Beijing Municipal Bureau of Agriculture, Beijing, 100101, China
| | - D Sun
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, National Engineering Laboratory for Animal Breeding, China Agricultural University, Beijing, 100193, China
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19
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Johannsen J, Bierhals T, Deindl P, Hecher L, Hermann K, Hempel M, Kloth K, Denecke J. Excessive Seizure Clusters in an Otherwise Well-Controlled Epilepsy as a Possible Hallmark of Untreated Vitamin B6-Responsive Epilepsy due to a Homozygous PLPBP Missense Variant. J Pediatr Genet 2019; 8:222-225. [PMID: 31687261 DOI: 10.1055/s-0039-1685501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Accepted: 03/11/2019] [Indexed: 01/14/2023]
Abstract
Recently, mutations in the PLPBP gene were described as a novel cause for vitamin B6-responsive epilepsy. We report the outcome in case of a male adolescent with a novel homozygous missense variant in PLPBP who was never treated with pyridoxine until the age of 16 years. He presented with only mild cognitive impairment and an early-onset, well-controlled epilepsy. In our patient, excessive seizure clusters and anxiety states occurred intermittently, suggesting that the combination might be a hallmark in untreated patients. Thus, mutations in PLPBP should be addressed even in adolescent patients with only mild learning disabilities and relatively good seizure control over the years.
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Affiliation(s)
- Jessika Johannsen
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tatjana Bierhals
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Philipp Deindl
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Laura Hecher
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Katharina Hermann
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Maja Hempel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Katja Kloth
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jonas Denecke
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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20
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Forcada-Nadal A, Llácer JL, Contreras A, Marco-Marín C, Rubio V. The P II-NAGK-PipX-NtcA Regulatory Axis of Cyanobacteria: A Tale of Changing Partners, Allosteric Effectors and Non-covalent Interactions. Front Mol Biosci 2018; 5:91. [PMID: 30483512 PMCID: PMC6243067 DOI: 10.3389/fmolb.2018.00091] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 10/18/2018] [Indexed: 11/13/2022] Open
Abstract
PII, a homotrimeric very ancient and highly widespread (bacteria, archaea, plants) key sensor-transducer protein, conveys signals of abundance or poorness of carbon, energy and usable nitrogen, converting these signals into changes in the activities of channels, enzymes, or of gene expression. PII sensing is mediated by the PII allosteric effectors ATP, ADP (and, in some organisms, AMP), 2-oxoglutarate (2OG; it reflects carbon abundance and nitrogen scarcity) and, in many plants, L-glutamine. Cyanobacteria have been crucial for clarification of the structural bases of PII function and regulation. They are the subject of this review because the information gathered on them provides an overall structure-based view of a PII regulatory network. Studies on these organisms yielded a first structure of a PII complex with an enzyme, (N-acetyl-Lglutamate kinase, NAGK), deciphering how PII can cause enzyme activation, and how it promotes nitrogen stockpiling as arginine in cyanobacteria and plants. They have also revealed the first clear-cut mechanism by which PII can control gene expression. A small adaptor protein, PipX, is sequestered by PII when nitrogen is abundant and is released when is scarce, swapping partner by binding to the 2OG-activated transcriptional regulator NtcA, co-activating it. The structures of PII-NAGK, PII-PipX, PipX alone, of NtcA in inactive and 2OG-activated forms and as NtcA-2OG-PipX complex, explain structurally PII regulatory functions and reveal the changing shapes and interactions of the T-loops of PII depending on the partner and on the allosteric effectors bound to PII. Cyanobacterial studies have also revealed that in the PII-PipX complex PipX binds an additional transcriptional factor, PlmA, thus possibly expanding PipX roles beyond NtcA-dependency. Further exploration of these roles has revealed a functional interaction of PipX with PipY, a pyridoxal-phosphate (PLP) protein involved in PLP homeostasis whose mutations in the human ortholog cause epilepsy. Knowledge of cellular levels of the different components of this PII-PipX regulatory network and of KD values for some of the complexes provides the basic background for gross modeling of the system at high and low nitrogen abundance. The cyanobacterial network can guide searches for analogous components in other organisms, particularly of PipX functional analogs.
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Affiliation(s)
- Alicia Forcada-Nadal
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - José Luis Llácer
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras - Instituto de Salud Carlos III, Valencia, Spain
| | - Asunción Contreras
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Clara Marco-Marín
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras - Instituto de Salud Carlos III, Valencia, Spain
| | - Vicente Rubio
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras - Instituto de Salud Carlos III, Valencia, Spain
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