1
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Fitzpatrick PF. The aromatic amino acid hydroxylases: Structures, catalysis, and regulation of phenylalanine hydroxylase, tyrosine hydroxylase, and tryptophan hydroxylase. Arch Biochem Biophys 2023; 735:109518. [PMID: 36639008 DOI: 10.1016/j.abb.2023.109518] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/01/2023] [Accepted: 01/06/2023] [Indexed: 01/12/2023]
Abstract
The aromatic amino acid hydroxylases phenylalanine hydroxylase, tyrosine hydroxylase, and tryptophan hydroxylase are non-heme iron enzymes that catalyze key physiological reactions. This review discusses the present understanding of the common catalytic mechanism of these enzymes and recent advances in understanding the relationship between their structures and their regulation.
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Affiliation(s)
- Paul F Fitzpatrick
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, 78229, USA.
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2
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Zhou L, Su J, Long J, Tao R, Tang W, Qin F, Liu N, Wang Y, Jiao Y, Hu Y, Jiang L, Li L, Yang Y, Yao S. A universal strategy for AAV delivery of base editors to correct genetic point mutations in neonatal PKU mice. Mol Ther Methods Clin Dev 2022; 24:230-240. [PMID: 35141352 PMCID: PMC8803597 DOI: 10.1016/j.omtm.2022.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 01/05/2022] [Indexed: 02/08/2023]
Abstract
Base editing tools enabled efficient conversion of C:G or A:T base pairs to T:A or G:C, which are especially powerful for targeting monogenic lesions. However, in vivo correction of disease-causing mutations is still less efficient because of the large size of base editors. Here, we designed a dual adeno-associated virus (AAV) strategy for in vivo delivery of base editors, in which deaminases were linked to Cas9 through the interaction of GCN4 peptide and its single chain variable fragment (scFv) antibody. We found that one or two copies of GCN4 peptide were enough for the assembly of base editors and produced robust targeted editing. By optimization of single-guide RNAs (sgRNAs) that target phenylketonuria (PKU) mutation, we were able to achieve up to 27.7% correction in vitro. In vivo delivery of this dual AAV base editing system resulted in efficient correction of PKU-related mutation in neonatal mice and subsequent rescue of hyperphenylalaninemia-associated syndromes. Considering the similarity between Cas9 proteins from different organisms, our delivery strategy will be compatible with other Cas9-derived base editors.
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Affiliation(s)
- Lifang Zhou
- Laboratory of Biotherapy, National Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Renmin Nanlu 17, Chengdu 610041, Sichuan, China
| | - Jing Su
- Laboratory of Biotherapy, National Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Renmin Nanlu 17, Chengdu 610041, Sichuan, China
| | - Jie Long
- Laboratory of Biotherapy, National Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Renmin Nanlu 17, Chengdu 610041, Sichuan, China
| | - Rui Tao
- Laboratory of Biotherapy, National Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Renmin Nanlu 17, Chengdu 610041, Sichuan, China
| | - Wenling Tang
- Laboratory of Biotherapy, National Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Renmin Nanlu 17, Chengdu 610041, Sichuan, China
| | - Fengming Qin
- Laboratory of Biotherapy, National Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Renmin Nanlu 17, Chengdu 610041, Sichuan, China
| | - Nan Liu
- Laboratory of Biotherapy, National Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Renmin Nanlu 17, Chengdu 610041, Sichuan, China
| | - Yanhong Wang
- Laboratory of Biotherapy, National Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Renmin Nanlu 17, Chengdu 610041, Sichuan, China
| | - Yaoge Jiao
- Laboratory of Biotherapy, National Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Renmin Nanlu 17, Chengdu 610041, Sichuan, China
| | - Yun Hu
- Laboratory of Biotherapy, National Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Renmin Nanlu 17, Chengdu 610041, Sichuan, China
| | - Lurong Jiang
- Laboratory of Biotherapy, National Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Renmin Nanlu 17, Chengdu 610041, Sichuan, China
| | - Li Li
- Laboratory of Biotherapy, National Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Renmin Nanlu 17, Chengdu 610041, Sichuan, China
| | - Yang Yang
- Laboratory of Biotherapy, National Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Renmin Nanlu 17, Chengdu 610041, Sichuan, China
| | - Shaohua Yao
- Laboratory of Biotherapy, National Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Renmin Nanlu 17, Chengdu 610041, Sichuan, China
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3
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Mordhorst A, Dhandapani P, Matthes S, Mosienko V, Rothe M, Todiras M, Self J, Schunck WH, Schütz A, Bader M, Alenina N. Phenylalanine hydroxylase contributes to serotonin synthesis in mice. FASEB J 2021; 35:e21648. [PMID: 33993565 DOI: 10.1096/fj.202100366r] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 04/11/2021] [Accepted: 04/21/2021] [Indexed: 12/31/2022]
Abstract
Serotonin is an important signaling molecule in the periphery and in the brain. The hydroxylation of tryptophan is the first and rate-limiting step of its synthesis. In most vertebrates, two enzymes have been described to catalyze this step, tryptophan hydroxylase (TPH) 1 and 2, with expression localized to peripheral and neuronal cells, respectively. However, animals lacking both TPH isoforms still exhibit about 10% of normal serotonin levels in the blood demanding an additional source of the monoamine. In this study, we provide evidence by the gain and loss of function approaches in in vitro and in vivo systems, including stable-isotope tracing in mice, that phenylalanine hydroxylase (PAH) is a third TPH in mammals. PAH contributes to serotonin levels in the blood, and may be important as a local source of serotonin in organs in which no other TPHs are expressed, such as liver and kidney.
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Affiliation(s)
- Alexander Mordhorst
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany.,Charite - University Medicine, Berlin, Germany
| | - Priyavathi Dhandapani
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Susann Matthes
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Valentina Mosienko
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | | | - Mihail Todiras
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,Nicolae Testemiţanu State University of Medicine and Pharmacy, Chișinău, Moldova
| | - Julie Self
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Wolf-Hagen Schunck
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Anja Schütz
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Michael Bader
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany.,Charite - University Medicine, Berlin, Germany.,Institute for Biology, University of Lübeck, Lübeck, Germany
| | - Natalia Alenina
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany.,Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia.,Institute of Cytology, Russian Academy of Science, St. Petersburg, Russia
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4
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Nehela Y, Killiny N. Diaphorina citri Genome Possesses a Complete Melatonin Biosynthesis Pathway Differentially Expressed under the Influence of the Phytopathogenic Bacterium, Candidatus Liberibacter asiaticus. INSECTS 2021; 12:317. [PMID: 33916117 PMCID: PMC8065666 DOI: 10.3390/insects12040317] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 03/29/2021] [Accepted: 03/29/2021] [Indexed: 11/17/2022]
Abstract
Melatonin is synthesized from the amino acid L-tryptophan via the shikimic acid pathway and ubiquitously distributed in both prokaryotes and eukaryotes. Although most of melatonin biosynthesis genes were characterized in several plants and animal species including the insect model, Drosophila melanogaster, none of these enzymes have been identified from the Asian citrus psyllid, Diaphorina citri. We used comprehensive in silico analysis and gene expression techniques to identify the melatonin biosynthesis-related genes of D. citri and to evaluate the expression patterns of these genes within the adults of D. citri with gradient infection rates (0, 28, 34, 50, 58, and 70%) of the phytopathogenic bacterium Candidatus Liberibacter asiaticus and after the treatment with exogenous melatonin. We showed that the D. citri genome possesses six putative melatonin biosynthesis-related genes including two putative tryptophan 5-hydroxylase (DcT5H-1 and DcT5H-2), a putative aromatic amino acid decarboxylase (DcAADC), two putative arylalkylamine N-acetyltransferase (DcAANAT-1 and DcAANAT-2), and putative N-acetylserotonin O-methyltransferase (DcASMT). The infection with Ca. L. asiaticus decreased the transcript levels of all predicted genes in the adults of D. citri. Moreover, melatonin supplementation induced their expression levels in both healthy and Ca. L. asiaticus-infected psyllids. These findings confirm the association of these genes with the melatonin biosynthesis pathway.
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Affiliation(s)
- Yasser Nehela
- Citrus Research and Education Center, Department of Plant Pathology, University of Florida, 700 Experiment Station Rd., Lake Alfred, FL 33850, USA;
- Department of Agricultural Botany, Faculty of Agriculture, Tanta University, Tanta 31511, Egypt
| | - Nabil Killiny
- Citrus Research and Education Center, Department of Plant Pathology, University of Florida, 700 Experiment Station Rd., Lake Alfred, FL 33850, USA;
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5
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Moroz LL, Romanova DY, Kohn AB. Neural versus alternative integrative systems: molecular insights into origins of neurotransmitters. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190762. [PMID: 33550949 PMCID: PMC7935107 DOI: 10.1098/rstb.2019.0762] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2020] [Indexed: 12/18/2022] Open
Abstract
Transmitter signalling is the universal chemical language of any nervous system, but little is known about its early evolution. Here, we summarize data about the distribution and functions of neurotransmitter systems in basal metazoans as well as outline hypotheses of their origins. We explore the scenario that neurons arose from genetically different populations of secretory cells capable of volume chemical transmission and integration of behaviours without canonical synapses. The closest representation of this primordial organization is currently found in Placozoa, disk-like animals with the simplest known cell composition but complex behaviours. We propose that injury-related signalling was the evolutionary predecessor for integrative functions of early transmitters such as nitric oxide, ATP, protons, glutamate and small peptides. By contrast, acetylcholine, dopamine, noradrenaline, octopamine, serotonin and histamine were recruited as canonical neurotransmitters relatively later in animal evolution, only in bilaterians. Ligand-gated ion channels often preceded the establishment of novel neurotransmitter systems. Moreover, lineage-specific diversification of neurotransmitter receptors occurred in parallel within Cnidaria and several bilaterian lineages, including acoels. In summary, ancestral diversification of secretory signal molecules provides unique chemical microenvironments for behaviour-driven innovations that pave the way to complex brain functions and elementary cognition. This article is part of the theme issue 'Basal cognition: multicellularity, neurons and the cognitive lens'.
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Affiliation(s)
- Leonid L. Moroz
- Department of Neuroscience, McKnight Brain Institute and Whitney laboratory, University of Florida, 9505 Ocean shore Blvd, St Augustine, FL 32080, USA
| | - Daria Y. Romanova
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology of RAS, 5A Butlerova Street, Moscow 117485, Russia
| | - Andrea B. Kohn
- Department of Neuroscience, McKnight Brain Institute and Whitney laboratory, University of Florida, 9505 Ocean shore Blvd, St Augustine, FL 32080, USA
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6
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Chang E, Fu C, Coon SL, Alon S, Bozinoski M, Breymaier M, Bustos DM, Clokie SJ, Gothilf Y, Esnault C, Michael Iuvone P, Mason CE, Ochocinska MJ, Tovin A, Wang C, Xu P, Zhu J, Dale R, Klein DC. Resource: A multi-species multi-timepoint transcriptome database and webpage for the pineal gland and retina. J Pineal Res 2020; 69:e12673. [PMID: 32533862 PMCID: PMC7513311 DOI: 10.1111/jpi.12673] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 06/04/2020] [Accepted: 06/05/2020] [Indexed: 01/12/2023]
Abstract
The website and database https://snengs.nichd.nih.gov provides RNA sequencing data from multi-species analysis of the pineal glands from zebrafish (Danio rerio), chicken (White Leghorn), rat (Rattus novegicus), mouse (Mus musculus), rhesus macaque (Macaca mulatta), and human (Homo sapiens); in most cases, retinal data are also included along with results of the analysis of a mixture of RNA from tissues. Studies cover day and night conditions; in addition, a time series over multiple hours, a developmental time series and pharmacological experiments on rats are included. The data have been uniformly re-processed using the latest methods and assemblies to allow for comparisons between experiments and to reduce processing differences. The website presents search functionality, graphical representations, Excel tables, and track hubs of all data for detailed visualization in the UCSC Genome Browser. As more data are collected from investigators and improved genomes become available in the future, the website will be updated. This database is in the public domain and elements can be reproduced by citing the URL and this report. This effort makes the results of 21st century transcriptome profiling widely available in a user-friendly format that is expected to broadly influence pineal research.
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Affiliation(s)
- Eric Chang
- Bioinformatics and Scientific Programming CoreEunice Kennedy Shriver National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMDUSA
| | - Cong Fu
- Section on NeuroendocrinologyProgram in Developmental Endocrinology and GeneticsEunice Shriver Kennedy National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMDUSA
- Key Laboratory of Organ Regeneration & Transplantation of the Ministry of EducationThe First Hospital of Jilin UniversityChangchunChina
- Laboratory of Theoretical and Computational ChemistryInstitute of Theoretical ChemistryJilin UniversityChangchunChina
- National‐Local Joint Engineering Laboratory of Animal Models for Human DiseasesChangchunChina
| | - Steven L. Coon
- Section on NeuroendocrinologyProgram in Developmental Endocrinology and GeneticsEunice Shriver Kennedy National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMDUSA
- Molecular Genomics CoreOffice of the Scientific DirectorEunice Kennedy Shriver National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMDUSA
| | - Shahar Alon
- Department of NeurobiologyThe George S. Wise Faculty of Life Sciences, and Sagol School of NeuroscienceTel‐Aviv UniversityTel AvivIsrael
- Present address:
The Alexander Kofkin Faculty of EngineeringBar‐Ilan UniversityRamat‐GanIsrael
| | - Marjan Bozinoski
- Department of Physiology and Biophysics and the Institute for Computational BiomedicineWeill Cornell Medical CollegeNew YorkNYUSA
| | - Matthew Breymaier
- Computer Support Services CoreEunice Shriver Kennedy National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMDUSA
| | - Diego M. Bustos
- Section on NeuroendocrinologyProgram in Developmental Endocrinology and GeneticsEunice Shriver Kennedy National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMDUSA
- Present address:
Instituto de Histología y Embriología de MendozaConsejo Nacional de Investigaciones Científicas y TécnicasMendozaArgentina
| | - Samuel J. Clokie
- Section on NeuroendocrinologyProgram in Developmental Endocrinology and GeneticsEunice Shriver Kennedy National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMDUSA
- Present address:
West Midlands Regional Genetics LaboratoriesBirmingham, Women’s and Children’s NHS Foundation TrustBirminghamUK
| | - Yoav Gothilf
- Department of NeurobiologyThe George S. Wise Faculty of Life Sciences, and Sagol School of NeuroscienceTel‐Aviv UniversityTel AvivIsrael
| | - Caroline Esnault
- Bioinformatics and Scientific Programming CoreEunice Kennedy Shriver National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMDUSA
| | - P. Michael Iuvone
- Departments of Ophthalmology and Pharmacology & Chemical BiologyEmory University School of MedicineAtlantaGAUSA
| | - Christopher E. Mason
- Department of Physiology and Biophysics and the Institute for Computational BiomedicineWeill Cornell Medical CollegeNew YorkNYUSA
| | - Margaret J. Ochocinska
- Section on NeuroendocrinologyProgram in Developmental Endocrinology and GeneticsEunice Shriver Kennedy National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMDUSA
- Present address:
National Heart, Lung and Blood InstituteNational Institutes of HealthBethesdaMDUSA
| | - Adi Tovin
- Department of NeurobiologyThe George S. Wise Faculty of Life Sciences, and Sagol School of NeuroscienceTel‐Aviv UniversityTel AvivIsrael
- Present address:
The Faculty of Life SciencesBar‐Ilan UniversityRamat‐GanIsrael
| | - Charles Wang
- Center for GenomicsSchool of MedicineLoma Linda UniversityLoma LindaCAUSA
| | - Pinxian Xu
- Department of Genetics and Genomic SciencesMount Sinai School of Medicine Icahn Medical InstituteNew YorkNYUSA
| | - Jinhang Zhu
- United States Food and Drug Administration’s National Center for Toxicological Research, Food and Drug AdministrationJeffersonARUSA
- Department of PhysiologySchool of Basic Medical SciencesAnhui Medical UniversityHefeiChina
| | - Ryan Dale
- Bioinformatics and Scientific Programming CoreEunice Kennedy Shriver National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMDUSA
| | - David C. Klein
- Section on NeuroendocrinologyProgram in Developmental Endocrinology and GeneticsEunice Shriver Kennedy National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMDUSA
- Office of the Scientific DirectorEunice Kennedy Shriver National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMDUSA
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Dufour S, Quérat B, Tostivint H, Pasqualini C, Vaudry H, Rousseau K. Origin and Evolution of the Neuroendocrine Control of Reproduction in Vertebrates, With Special Focus on Genome and Gene Duplications. Physiol Rev 2019; 100:869-943. [PMID: 31625459 DOI: 10.1152/physrev.00009.2019] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In humans, as in the other mammals, the neuroendocrine control of reproduction is ensured by the brain-pituitary gonadotropic axis. Multiple internal and environmental cues are integrated via brain neuronal networks, ultimately leading to the modulation of the activity of gonadotropin-releasing hormone (GnRH) neurons. The decapeptide GnRH is released into the hypothalamic-hypophysial portal blood system and stimulates the production of pituitary glycoprotein hormones, the two gonadotropins luteinizing hormone and follicle-stimulating hormone. A novel actor, the neuropeptide kisspeptin, acting upstream of GnRH, has attracted increasing attention in recent years. Other neuropeptides, such as gonadotropin-inhibiting hormone/RF-amide related peptide, and other members of the RF-amide peptide superfamily, as well as various nonpeptidic neuromediators such as dopamine and serotonin also provide a large panel of stimulatory or inhibitory regulators. This paper addresses the origin and evolution of the vertebrate gonadotropic axis. Brain-pituitary neuroendocrine axes are typical of vertebrates, the pituitary gland, mediator and amplifier of brain control on peripheral organs, being a vertebrate innovation. The paper reviews, from molecular and functional perspectives, the evolution across vertebrate radiation of some key actors of the vertebrate neuroendocrine control of reproduction and traces back their origin along the vertebrate lineage and in other metazoa before the emergence of vertebrates. A focus is given on how gene duplications, resulting from either local events or from whole genome duplication events, and followed by paralogous gene loss or conservation, might have shaped the evolutionary scenarios of current families of key actors of the gonadotropic axis.
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Affiliation(s)
- Sylvie Dufour
- Muséum National d'Histoire Naturelle, Biology of Aquatic Organisms and Ecosystems, CNRS, IRD, Sorbonne Université, Université Caen Normandie, Université des Antilles, Paris, France; Université Paris Diderot, Sorbonne Paris Cite, Biologie Fonctionnelle et Adaptative, Paris, France; INSERM U1133, Physiologie de l'axe Gonadotrope, Paris, France; Muséum National d'Histoire Naturelle, Physiologie Moléculaire et Adaptation, Muséum National d'Histoire Naturelle, Paris, France; Université Paris-Saclay, Université Paris-Sud, CNRS, Paris-Saclay Institute of Neuroscience (UMR 9197), Gif-sur-Yvette, France; and Université de Rouen Normandie, Rouen, France
| | - Bruno Quérat
- Muséum National d'Histoire Naturelle, Biology of Aquatic Organisms and Ecosystems, CNRS, IRD, Sorbonne Université, Université Caen Normandie, Université des Antilles, Paris, France; Université Paris Diderot, Sorbonne Paris Cite, Biologie Fonctionnelle et Adaptative, Paris, France; INSERM U1133, Physiologie de l'axe Gonadotrope, Paris, France; Muséum National d'Histoire Naturelle, Physiologie Moléculaire et Adaptation, Muséum National d'Histoire Naturelle, Paris, France; Université Paris-Saclay, Université Paris-Sud, CNRS, Paris-Saclay Institute of Neuroscience (UMR 9197), Gif-sur-Yvette, France; and Université de Rouen Normandie, Rouen, France
| | - Hervé Tostivint
- Muséum National d'Histoire Naturelle, Biology of Aquatic Organisms and Ecosystems, CNRS, IRD, Sorbonne Université, Université Caen Normandie, Université des Antilles, Paris, France; Université Paris Diderot, Sorbonne Paris Cite, Biologie Fonctionnelle et Adaptative, Paris, France; INSERM U1133, Physiologie de l'axe Gonadotrope, Paris, France; Muséum National d'Histoire Naturelle, Physiologie Moléculaire et Adaptation, Muséum National d'Histoire Naturelle, Paris, France; Université Paris-Saclay, Université Paris-Sud, CNRS, Paris-Saclay Institute of Neuroscience (UMR 9197), Gif-sur-Yvette, France; and Université de Rouen Normandie, Rouen, France
| | - Catherine Pasqualini
- Muséum National d'Histoire Naturelle, Biology of Aquatic Organisms and Ecosystems, CNRS, IRD, Sorbonne Université, Université Caen Normandie, Université des Antilles, Paris, France; Université Paris Diderot, Sorbonne Paris Cite, Biologie Fonctionnelle et Adaptative, Paris, France; INSERM U1133, Physiologie de l'axe Gonadotrope, Paris, France; Muséum National d'Histoire Naturelle, Physiologie Moléculaire et Adaptation, Muséum National d'Histoire Naturelle, Paris, France; Université Paris-Saclay, Université Paris-Sud, CNRS, Paris-Saclay Institute of Neuroscience (UMR 9197), Gif-sur-Yvette, France; and Université de Rouen Normandie, Rouen, France
| | - Hubert Vaudry
- Muséum National d'Histoire Naturelle, Biology of Aquatic Organisms and Ecosystems, CNRS, IRD, Sorbonne Université, Université Caen Normandie, Université des Antilles, Paris, France; Université Paris Diderot, Sorbonne Paris Cite, Biologie Fonctionnelle et Adaptative, Paris, France; INSERM U1133, Physiologie de l'axe Gonadotrope, Paris, France; Muséum National d'Histoire Naturelle, Physiologie Moléculaire et Adaptation, Muséum National d'Histoire Naturelle, Paris, France; Université Paris-Saclay, Université Paris-Sud, CNRS, Paris-Saclay Institute of Neuroscience (UMR 9197), Gif-sur-Yvette, France; and Université de Rouen Normandie, Rouen, France
| | - Karine Rousseau
- Muséum National d'Histoire Naturelle, Biology of Aquatic Organisms and Ecosystems, CNRS, IRD, Sorbonne Université, Université Caen Normandie, Université des Antilles, Paris, France; Université Paris Diderot, Sorbonne Paris Cite, Biologie Fonctionnelle et Adaptative, Paris, France; INSERM U1133, Physiologie de l'axe Gonadotrope, Paris, France; Muséum National d'Histoire Naturelle, Physiologie Moléculaire et Adaptation, Muséum National d'Histoire Naturelle, Paris, France; Université Paris-Saclay, Université Paris-Sud, CNRS, Paris-Saclay Institute of Neuroscience (UMR 9197), Gif-sur-Yvette, France; and Université de Rouen Normandie, Rouen, France
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8
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Coon SL, Fu C, Hartley SW, Holtzclaw L, Mays JC, Kelly MC, Kelley MW, Mullikin JC, Rath MF, Savastano LE, Klein DC. Single Cell Sequencing of the Pineal Gland: The Next Chapter. Front Endocrinol (Lausanne) 2019; 10:590. [PMID: 31616371 PMCID: PMC6764290 DOI: 10.3389/fendo.2019.00590] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 08/12/2019] [Indexed: 11/25/2022] Open
Abstract
The analysis of pineal cell biology has undergone remarkable development as techniques have become available which allow for sequencing of entire transcriptomes and, most recently, the sequencing of the transcriptome of individual cells. Identification of at least nine distinct cell types in the rat pineal gland has been made possible, allowing identification of the precise cells of origin and expression of transcripts for the first time. Here the history and current state of knowledge generated by these transcriptomic efforts is reviewed, with emphasis on the insights suggested by the findings.
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Affiliation(s)
- Steven L. Coon
- Molecular Genomics Core, Office of the Scientific Director, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Cong Fu
- Key Laboratory of Organ Regeneration & Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
- National-Local Joint Engineering Laboratory of Animal Models for Human Diseases, Changchun, China
| | - Steven W. Hartley
- Comparative Genomics Analysis Unit, Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Lynne Holtzclaw
- Microscopy and Imaging Core, Office of the Scientific Director, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Joseph C. Mays
- Institute on Systems Genetics, New York University School of Medicine, New York, NY, United States
| | - Michael C. Kelly
- Single Cell Analysis Facility, Frederick National Lab for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Matthew W. Kelley
- Section on Developmental Neuroscience, Laboratory of Cochlear Development, Division of Intramural Research, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
| | - James C. Mullikin
- National Institutes of Health Intramural Sequencing Center, National Human Genome Research Institute, National Institutes of Health, Rockville, MD, United States
| | - Martin F. Rath
- Department of Neuroscience, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Luis E. Savastano
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI, United States
| | - David C. Klein
- Office of the Scientific Director, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
- *Correspondence: David C. Klein
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9
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Szigetvari PD, Muruganandam G, Kallio JP, Hallin EI, Fossbakk A, Loris R, Kursula I, Møller LB, Knappskog PM, Kursula P, Haavik J. The quaternary structure of human tyrosine hydroxylase: effects of dystonia-associated missense variants on oligomeric state and enzyme activity. J Neurochem 2018; 148:291-306. [PMID: 30411798 PMCID: PMC6587854 DOI: 10.1111/jnc.14624] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 10/26/2018] [Accepted: 10/31/2018] [Indexed: 01/27/2023]
Abstract
Abstract Tyrosine hydroxylase (TH) is a multi‐domain, homo‐oligomeric enzyme that catalyses the rate‐limiting step of catecholamine neurotransmitter biosynthesis. Missense variants of human TH are associated with a recessive neurometabolic disease with low levels of brain dopamine and noradrenaline, resulting in a variable clinical picture, from progressive brain encephalopathy to adolescent onset DOPA‐responsive dystonia (DRD). We expressed isoform 1 of human TH (hTH1) and its dystonia‐associated missense variants in E. coli, analysed their quaternary structure and thermal stability using size‐exclusion chromatography, circular dichroism, multi‐angle light scattering, transmission electron microscopy, small‐angle X‐ray scattering and assayed hydroxylase activity. Wild‐type (WT) hTH1 was a mixture of enzymatically stable tetramers (85.6%) and octamers (14.4%), with little interconversion between these species. We also observed small amounts of higher order assemblies of long chains of enzyme by transmission electron microscopy. To investigate the role of molecular assemblies in the pathogenesis of DRD, we compared the structure of WT hTH1 with the DRD‐associated variants R410P and D467G that are found in vicinity of the predicted subunit interfaces. In contrast to WT hTH1, R410P and D467G were mixtures of tetrameric and dimeric species. Inspection of the available structures revealed that Arg‐410 and Asp‐467 are important for maintaining the stability and oligomeric structure of TH. Disruption of the normal quaternary enzyme structure by missense variants is a new molecular mechanism that may explain the loss of TH enzymatic activity in DRD. Unstable missense variants could be targets for pharmacological intervention in DRD, aimed to re‐establish the normal oligomeric state of TH. ![]()
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Affiliation(s)
- Peter D Szigetvari
- Department of Biomedicine, University of Bergen, Bergen, Norway.,K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway
| | - Gopinath Muruganandam
- VIB-VUB Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium.,Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Juha P Kallio
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Erik I Hallin
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Agnete Fossbakk
- K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway
| | - Remy Loris
- VIB-VUB Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium.,Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Inari Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway.,Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.,Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Lisbeth B Møller
- Applied Human Molecular Genetics, Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Per M Knappskog
- K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway.,Department of Clinical Science, University of Bergen, Bergen, Norway.,Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway.,Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Jan Haavik
- Department of Biomedicine, University of Bergen, Bergen, Norway.,K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway.,Division of Psychiatry, Haukeland University Hospital, Bergen, Norway
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10
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Koshimizu H, Hirata N, Takao K, Toyama K, Ichinose T, Furuya S, Miyakawa T. Comprehensive behavioral analysis and quantification of brain free amino acids of C57BL/6J congenic mice carrying the 1473G allele in tryptophan hydroxylase-2. Neuropsychopharmacol Rep 2018; 39:56-60. [PMID: 30472790 PMCID: PMC7292325 DOI: 10.1002/npr2.12041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 10/22/2018] [Accepted: 10/23/2018] [Indexed: 12/16/2022] Open
Abstract
Aim Tryptophan hydroxylase 2 (Tph2) is a rate‐limiting enzyme for the biosynthesis of 5‐hydroxytryptamine (5‐HT, serotonin). Previous studies have reported that C1473G polymorphism of the murine Tph2 gene leads to decreased 5‐HT levels in the brain and abnormal behavioral phenotypes, such as impaired anxiety‐ and depression‐like behaviors. In this study, to confirm the effect of the C1473G polymorphism on mouse phenotypes, we conducted a comprehensive battery of behavioral tests and measured the amounts of brain free amino acids involved in the production of 5‐HT. Methods We obtained C57BL/6J congenic mice that were homozygous for the 1473G allele of Tph2 (1473G) and subjected them and their wild‐type littermates (1473C) to a battery of behavioral tests. Using reverse‐phase high‐performance liquid chromatography (HPLC), we measured the amounts of free amino acids in the 5‐HT and epinephrine synthetic/metabolic pathways in the frontal cortex, hippocampus, striatum, and midbrain. Results We failed to detect significant differences between genotypes in depression‐like behaviors, anxiety‐like behaviors, social behaviors, sensorimotor gaiting, or learning and memory, while 1473G mice exhibited a nominally significant impairment in gait analysis, which failed to reach study‐wide significance. In the HPLC analysis, there were no significant differences in the amounts of 5‐HT, dopamine, norepinephrine, and epinephrine in the frontal cortex, hippocampus, striatum, and midbrain. Conclusion Our findings do not support the idea that congenic C57BL/6J mice carrying the 1473G allele may represent an animal model of mood disorder under normal conditions without stress. We assessed the behavioral and biochemical phenotypes of congenic C57BL/6J mice carrying the 1473G allele and failed to identify significant differences between the 1473G allele‐carrying mice and their wild‐type littermates. Thus, our findings do not support the use of 1473G allele‐carrying C57BL/6J mice as an animal model of mood disorder under normal conditions without stress.
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Affiliation(s)
- Hisatsugu Koshimizu
- Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Japan
| | - Nao Hirata
- Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Japan
| | - Keizo Takao
- Life Science Research Center, University of Toyama, Toyama, Japan
| | - Keiko Toyama
- Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Japan
| | - Takashi Ichinose
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
| | - Shigeki Furuya
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
| | - Tsuyoshi Miyakawa
- Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Japan
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11
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Parthasarathy A, Cross PJ, Dobson RCJ, Adams LE, Savka MA, Hudson AO. A Three-Ring Circus: Metabolism of the Three Proteogenic Aromatic Amino Acids and Their Role in the Health of Plants and Animals. Front Mol Biosci 2018; 5:29. [PMID: 29682508 PMCID: PMC5897657 DOI: 10.3389/fmolb.2018.00029] [Citation(s) in RCA: 160] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 03/21/2018] [Indexed: 12/19/2022] Open
Abstract
Tyrosine, phenylalanine and tryptophan are the three aromatic amino acids (AAA) involved in protein synthesis. These amino acids and their metabolism are linked to the synthesis of a variety of secondary metabolites, a subset of which are involved in numerous anabolic pathways responsible for the synthesis of pigment compounds, plant hormones and biological polymers, to name a few. In addition, these metabolites derived from the AAA pathways mediate the transmission of nervous signals, quench reactive oxygen species in the brain, and are involved in the vast palette of animal coloration among others pathways. The AAA and metabolites derived from them also have integral roles in the health of both plants and animals. This review delineates the de novo biosynthesis of the AAA by microbes and plants, and the branching out of AAA metabolism into major secondary metabolic pathways in plants such as the phenylpropanoid pathway. Organisms that do not possess the enzymatic machinery for the de novo synthesis of AAA must obtain these primary metabolites from their diet. Therefore, the metabolism of AAA by the host animal and the resident microflora are important for the health of all animals. In addition, the AAA metabolite-mediated host-pathogen interactions in general, as well as potential beneficial and harmful AAA-derived compounds produced by gut bacteria are discussed. Apart from the AAA biosynthetic pathways in plants and microbes such as the shikimate pathway and the tryptophan pathway, this review also deals with AAA catabolism in plants, AAA degradation via the monoamine and kynurenine pathways in animals, and AAA catabolism via the 3-aryllactate and kynurenine pathways in animal-associated microbes. Emphasis will be placed on structural and functional aspects of several key AAA-related enzymes, such as shikimate synthase, chorismate mutase, anthranilate synthase, tryptophan synthase, tyrosine aminotransferase, dopachrome tautomerase, radical dehydratase, and type III CoA-transferase. The past development and current potential for interventions including the development of herbicides and antibiotics that target key enzymes in AAA-related pathways, as well as AAA-linked secondary metabolism leading to antimicrobials are also discussed.
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Affiliation(s)
- Anutthaman Parthasarathy
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY, United States
| | - Penelope J. Cross
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Renwick C. J. Dobson
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, Australia
| | - Lily E. Adams
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY, United States
| | - Michael A. Savka
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY, United States
| | - André O. Hudson
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY, United States
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12
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Wang S, Dong Z, Li S, Yin H, Zhao Z, Gao D, Ren G, Bao X. Identification and Expression Analysis of Tryptophan Hydroxylase in the Brain and Ventral Nerve Cord of Ragworm Neanthes japonica (Polychaeta, Annelida). Anat Rec (Hoboken) 2016; 300:415-424. [PMID: 27775878 DOI: 10.1002/ar.23506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 07/05/2016] [Accepted: 07/09/2016] [Indexed: 11/10/2022]
Abstract
Tryptophan hydroxylase (TPH) was stained in the central nervous system of the Neanthes japonica (Polychaeta, Annelida), using sheep anti-tryptophan hydroxylase antibody by the Streptavidin-Peroxidase immunohistochemical method and Colophony-Paraffin embedded section technique. The immunohistochemistry results revealed that the TPH is distributed in the brain and ventral nerve cord, which is consistent with that of serotonin (5-hydroxytryptamine, 5-HT) that labeled by anti-serotonin antibody. Using the rapid amplification of cDNA ends (RACE) technique, TPH cDNA cloned from Neanthes japonica's central nervous system was 1778bp, which encodes predicted protein of 463 amino acid residues. The co-localization of TPH and 5-HT indicated that the specific TPH was responsible for the central serotonin synthesis in the central nervous system of annelida, TPH and 5-HT not only could be as the novel mutual corroboration marker to detect serotonergic neurons, but also provides the evidences for the evolution of aromatic amino acid hydroxylase genes. Anat Rec, 300:415-424, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Shun Wang
- Laboratory of Insect Brain Neurobiology, School of Life Sciences, Northeast Normal University, Changchun, Jilin, 130024, People's Republic of China.,Department of Biochemistry and Molecular Biology, Jinzhou Medical University, Jinzhou, Liaoning, 121000, People's Republic of China
| | - Zhe Dong
- Department of Biochemistry and Molecular Biology, Jinzhou Medical University, Jinzhou, Liaoning, 121000, People's Republic of China
| | - Shen Li
- Department of Biochemistry and Molecular Biology, Jinzhou Medical University, Jinzhou, Liaoning, 121000, People's Republic of China
| | - Haotian Yin
- Department of Biochemistry and Molecular Biology, Jinzhou Medical University, Jinzhou, Liaoning, 121000, People's Republic of China
| | - Zhifu Zhao
- Laboratory of Insect Brain Neurobiology, School of Life Sciences, Northeast Normal University, Changchun, Jilin, 130024, People's Republic of China
| | - Dongmei Gao
- Laboratory of Insect Brain Neurobiology, School of Life Sciences, Northeast Normal University, Changchun, Jilin, 130024, People's Republic of China
| | - Guimin Ren
- Department of Biochemistry and Molecular Biology, Jinzhou Medical University, Jinzhou, Liaoning, 121000, People's Republic of China
| | - Xuexiang Bao
- Laboratory of Insect Brain Neurobiology, School of Life Sciences, Northeast Normal University, Changchun, Jilin, 130024, People's Republic of China
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13
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Patel D, Kopec J, Fitzpatrick F, McCorvie TJ, Yue WW. Structural basis for ligand-dependent dimerization of phenylalanine hydroxylase regulatory domain. Sci Rep 2016; 6:23748. [PMID: 27049649 PMCID: PMC4822156 DOI: 10.1038/srep23748] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 03/08/2016] [Indexed: 02/01/2023] Open
Abstract
The multi-domain enzyme phenylalanine hydroxylase (PAH) catalyzes the hydroxylation of dietary I-phenylalanine (Phe) to I-tyrosine. Inherited mutations that result in PAH enzyme deficiency are the genetic cause of the autosomal recessive disorder phenylketonuria. Phe is the substrate for the PAH active site, but also an allosteric ligand that increases enzyme activity. Phe has been proposed to bind, in addition to the catalytic domain, a site at the PAH N-terminal regulatory domain (PAH-RD), to activate the enzyme via an unclear mechanism. Here we report the crystal structure of human PAH-RD bound with Phe at 1.8 Å resolution, revealing a homodimer of ACT folds with Phe bound at the dimer interface. This work delivers the structural evidence to support previous solution studies that a binding site exists in the RD for Phe, and that Phe binding results in dimerization of PAH-RD. Consistent with our structural observation, a disease-associated PAH mutant impaired in Phe binding disrupts the monomer:dimer equilibrium of PAH-RD. Our data therefore support an emerging model of PAH allosteric regulation, whereby Phe binds to PAH-RD and mediates the dimerization of regulatory modules that would bring about conformational changes to activate the enzyme.
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Affiliation(s)
- Dipali Patel
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, UK OX3 7DQ
| | - Jolanta Kopec
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, UK OX3 7DQ
| | - Fiona Fitzpatrick
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, UK OX3 7DQ
| | - Thomas J McCorvie
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, UK OX3 7DQ
| | - Wyatt W Yue
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, UK OX3 7DQ
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14
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Roberts KM, Khan CA, Hinck CS, Fitzpatrick PF. Activation of phenylalanine hydroxylase by phenylalanine does not require binding in the active site. Biochemistry 2014; 53:7846-53. [PMID: 25453233 PMCID: PMC4270383 DOI: 10.1021/bi501183x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
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Phenylalanine
hydroxylase (PheH), a liver enzyme that catalyzes
the hydroxylation of excess phenylalanine in the diet to tyrosine,
is activated by phenylalanine. The lack of activity at low levels
of phenylalanine has been attributed to the N-terminus of the protein’s
regulatory domain acting as an inhibitory peptide by blocking substrate
access to the active site. The location of the site at which phenylalanine
binds to activate the enzyme is unknown, and both the active site
in the catalytic domain and a separate site in the N-terminal regulatory
domain have been proposed. Binding of catecholamines to the active-site
iron was used to probe the accessibility of the active site. Removal
of the regulatory domain increases the rate constants for association
of several catecholamines with the wild-type enzyme by ∼2-fold.
Binding of phenylalanine in the active site is effectively abolished
by mutating the active-site residue Arg270 to lysine. The kcat/Kphe value is
down 104 for the mutant enzyme, and the Km value for phenylalanine for the mutant enzyme is >0.5
M. Incubation of the R270K enzyme with phenylalanine also results
in a 2-fold increase in the rate constants for catecholamine binding.
The change in the tryptophan fluorescence emission spectrum seen in
the wild-type enzyme upon activation by phenylalanine is also seen
with the R270K mutant enzyme in the presence of phenylalanine. Both
results establish that activation of PheH by phenylalanine does not
require binding of the amino acid in the active site. This is consistent
with a separate allosteric site, likely in the regulatory domain.
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Affiliation(s)
- Kenneth M Roberts
- Department of Biochemistry, University of Texas Health Science Center , San Antonio, Texas 78229, United States
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15
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Complex molecular regulation of tyrosine hydroxylase. J Neural Transm (Vienna) 2014; 121:1451-81. [PMID: 24866693 DOI: 10.1007/s00702-014-1238-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 05/04/2014] [Indexed: 12/16/2022]
Abstract
Tyrosine hydroxylase, the rate-limiting enzyme in catecholamine biosynthesis, is strictly controlled by several interrelated regulatory mechanisms. Enzyme synthesis is controlled by epigenetic factors, transcription factors, and mRNA levels. Enzyme activity is regulated by end-product feedback inhibition. Phosphorylation of the enzyme is catalyzed by several protein kinases and dephosphorylation is mediated by two protein phosphatases that establish a sensitive process for regulating enzyme activity on a minute-to-minute basis. Interactions between tyrosine hydroxylase and other proteins introduce additional layers to the already tightly controlled production of catecholamines. Tyrosine hydroxylase degradation by the ubiquitin-proteasome coupled pathway represents yet another mechanism of regulation. Here, we revisit the myriad mechanisms that regulate tyrosine hydroxylase expression and activity and highlight their physiological importance in the control of catecholamine biosynthesis.
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16
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Roberts KM, Fitzpatrick PF. Mechanisms of tryptophan and tyrosine hydroxylase. IUBMB Life 2013; 65:350-7. [PMID: 23441081 DOI: 10.1002/iub.1144] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 01/02/2013] [Indexed: 11/11/2022]
Abstract
The aromatic amino acid hydroxylases tryptophan hydroxylase and tyrosine hydroxylase are responsible for the initial steps in the formation of serotonin and the catecholamine neurotransmitters, respectively. Both enzymes are nonheme iron-dependent monooxygenases that catalyze the insertion of one atom of molecular oxygen onto the aromatic ring of their amino acid substrates, using a tetrahydropterin as a two electron donor to reduce the second oxygen atom to water. This review discusses the current understanding of the catalytic mechanism of these two enzymes. The reaction occurs as two sequential half reactions: a reaction between the active site iron, oxygen, and the tetrahydropterin to form a reactive Fe(IV) O intermediate and hydroxylation of the amino acid by the Fe(IV) O. The mechanism of formation of the Fe(IV) O is unclear; however, considerable evidence suggests the formation of an Fe(II) -peroxypterin intermediate. The amino acid is hydroxylated by the Fe(IV) O intermediate in an electrophilic aromatic substitution mechanism.
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Affiliation(s)
- Kenneth M Roberts
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78228, USA
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17
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Daubner SC, Avila A, Bailey JO, Barrera D, Bermudez JY, Giles DH, Khan CA, Shaheen N, Thompson JW, Vasquez J, Oxley SP, Fitzpatrick PF. Mutagenesis of a specificity-determining residue in tyrosine hydroxylase establishes that the enzyme is a robust phenylalanine hydroxylase but a fragile tyrosine hydroxylase. Biochemistry 2013; 52:1446-55. [PMID: 23368961 PMCID: PMC3584195 DOI: 10.1021/bi400031n] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The aromatic amino acid hydroxylases tyrosine hydroxylase (TyrH) and phenylalanine hydroxylase (PheH) have essentially identical active sites; however, PheH is nearly incapable of hydroxylating tyrosine, while TyrH can readily hydroxylate both tyrosine and phenylalanine. Previous studies have indicated that Asp425 of TyrH is important in determining the substrate specificity of that enzyme [Daubner, S. C., Melendez, J., and Fitzpatrick, P. F. (2000) Biochemistry 39, 9652-9661]. Alanine-scanning mutagenesis of amino acids 423-427, a mobile loop containing Asp425, shows that only mutagenesis of Asp425 alters the activity of the enzyme significantly. Saturation mutagenesis of Asp425 results in large (up to 10(4)) decreases in the V(max) and V(max)/K(tyr) values for tyrosine hydroxylation, but only small decreases or even increases in the V(max) and V(max)/K(phe) values for phenylalanine hydroxylation. The decrease in the tyrosine hydroxylation activity of the mutant proteins is due to an uncoupling of tetrahydropterin oxidation from amino acid hydroxylation with tyrosine as the amino acid substrate. In contrast, with the exception of the D425W mutant, the extent of coupling of tetrahydropterin oxidation and amino acid hydroxylation is unaffected or increases with phenylalanine as the amino acid substrate. The decrease in the V(max) value with tyrosine as the substrate shows a negative correlation with the hydrophobicity of the amino acid residue at position 425. The results are consistent with a critical role of Asp425 being to prevent a hydrophobic interaction that results in a restricted active site in which hydroxylation of tyrosine does not occur.
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Affiliation(s)
- S. Colette Daubner
- Department of Biological Sciences, St. Mary’s University, San Antonio TX 78228
| | - Audrey Avila
- Department of Biological Sciences, St. Mary’s University, San Antonio TX 78228
| | - Johnathan O. Bailey
- Department of Biochemistry and Biophysics, Texas A&M University, College Station TX 77840
| | - Dimitrios Barrera
- Department of Chemistry and Biochemistry, St. Mary’s University, San Antonio TX 78228
| | - Jaclyn Y. Bermudez
- Department of Biological Sciences, St. Mary’s University, San Antonio TX 78228
| | - David H. Giles
- Department of Biochemistry, University of Texas Health Science Center San Antonio, San Antonio TX 78229
| | - Crystal A. Khan
- Department of Biochemistry, University of Texas Health Science Center San Antonio, San Antonio TX 78229
| | - Noel Shaheen
- Department of Biological Sciences, St. Mary’s University, San Antonio TX 78228
| | - Janie Womac Thompson
- Department of Biochemistry and Biophysics, Texas A&M University, College Station TX 77840
| | - Jessica Vasquez
- Department of Biochemistry and Biophysics, Texas A&M University, College Station TX 77840
| | - Susan P. Oxley
- Department of Chemistry and Biochemistry, St. Mary’s University, San Antonio TX 78228
| | - Paul F. Fitzpatrick
- Department of Biochemistry, University of Texas Health Science Center San Antonio, San Antonio TX 78229
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18
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Walther DJ, Stahlberg S, Vowinckel J. Novel roles for biogenic monoamines: from monoamines in transglutaminase-mediated post-translational protein modification to monoaminylation deregulation diseases. FEBS J 2011; 278:4740-55. [DOI: 10.1111/j.1742-4658.2011.08347.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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19
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Raghuveer K, Sudhakumari CC, Senthilkumaran B, Kagawa H, Dutta-Gupta A, Nagahama Y. Gender differences in tryptophan hydroxylase-2 mRNA, serotonin, and 5-hydroxytryptophan levels in the brain of catfish, Clarias gariepinus, during sex differentiation. Gen Comp Endocrinol 2011; 171:94-104. [PMID: 21156177 DOI: 10.1016/j.ygcen.2010.12.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 12/02/2010] [Accepted: 12/05/2010] [Indexed: 11/28/2022]
Abstract
Tryptophan hydroxylase (tph) is the key regulator in serotonin (5-HT) biosynthesis that stimulates the release of GnRH and gonadotropins by acting at the level of hypothalamo-hypophyseal axis. In brain, 5-HT is expressed predominantly in preoptic area-hypothalamus (POA-HYP) region in teleosts. Therefore, in the present study we isolated tph2 from catfish brain to evaluate its expression pattern in male and female brains during early development. Tph2 cloned from catfish brain is 2.768 Kb in length which encodes predicted protein of 488 amino acid residues. The characterization of recombinant tph2 was done by transient transfection in CHO cells. Tissue distribution of tph2 revealed ubiquitous expression except ovary. Real time PCR analysis in discrete regions of adult male brain revealed that tph2 mRNA was abundant in the POA-HYP and optic tectum+cerebellum+thalamus (OCT) regions. Differential expression of tph2 was observed at mRNA and protein levels in the POA-HYP and OCT regions of male and female brains during development that further correlate with the 5-hydroxytryptophan (5-HTP) and 5-HT levels measured using HPLC method in these regions of male and female brains. Tph2 immunoreactive neurons were observed in different regions of brain at 50 days post hatch using catfish specific tph2 antibody. Changes in tph2 mRNA expression, 5-HTP, and 5-HT levels in the POA-HYP+OCT region of brains of methyltestosterone and para-chlorophenylalanine treated fishes during development further endorse our results. Based on our results, we propose that the serotonergic system is involved in brain sex differentiation in teleosts.
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Affiliation(s)
- K Raghuveer
- Department of Animal Sciences, School of Life Sciences--Centre for Advanced Studies, University of Hyderabad, P.O. Central University, Hyderabad 500 046, Andhra Pradesh, India
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20
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Rahman S, Khan IA, Thomas P. Tryptophan hydroxylase: a target for neuroendocrine disruption. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2011; 14:473-494. [PMID: 21790322 DOI: 10.1080/10937404.2011.578563] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Tryptophan hydroxylase (TPH), the rate-limiting enzyme in serotonin (5-HT) synthesis, performs an essential role in the maintenance of serotonergic functions in the central nervous system (CNS), including regulation of the neuroendocrine system controlling reproduction. The results of recent studies in a teleost model of neuroendocrine disruption, Atlantic croaker, indicated that hypothalamic TPH is a major site of interference of hypothalamic-pituitary-gonadal function by environmental stressors. The effects of exposure to two different types of environmental stressors, low dissolved oxygen (hypoxia) and a polychlorinated biphenyl mixture (Aroclor 1254), on the stimulatory brain serotonergic system controlling reproductive neuroendocrine function in Atlantic croaker are reviewed. Exposure to both stressors produced decreases in TPH activity, which were accompanied by a fall in hypothalamic 5-HT and gonadotropin-releasing hormone (GnRH I) content in the preoptic-anterior hypothalamic area and were associated with reduction in luteinizing hormone (LH) secretion and gonadal development. Pharmacological restoration of hypothalamic 5-HT levels after exposure to both stressors also restored neuroendocrine and reproductive functions, indicating that the serotonergic system is an important site for hypoxia- and Aroclor 1254-induced inhibition of reproductive neuroendocrine functions. The mechanisms underlying downregulation of TPH activity by these stressors remain unclear but may involve alterations in hypothalamic antioxidant status. In support of this hypothesis, treatment with an antioxidant, vitamin E, was found to reverse the inhibitory effects of Aroclor 1254 on TPH activity. The results suggest that TPH is a major target for neuroendocrine disruption by diverse environmental stressors.
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Affiliation(s)
- Saydur Rahman
- Marine Science Institute, University of Texas at Austin, Port Aransas, Texas 78373, USA
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Li J, Dangott LJ, Fitzpatrick PF. Regulation of phenylalanine hydroxylase: conformational changes upon phenylalanine binding detected by hydrogen/deuterium exchange and mass spectrometry. Biochemistry 2010; 49:3327-35. [PMID: 20307070 DOI: 10.1021/bi1001294] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Phenylalanine acts as an allosteric activator of the tetrahydropterin-dependent enzyme phenylalanine hydroxylase. Hydrogen/deuterium exchange monitored by mass spectrometry has been used to gain insight into local conformational changes accompanying activation of rat phenylalanine hydroxylase by phenylalanine. Peptides in the regulatory and catalytic domains that lie in the interface between these two domains show large increases in the extent of deuterium incorporation from solvent in the presence of phenylalanine. In contrast, the effects of phenylalanine on the exchange kinetics of a mutant enzyme lacking the regulatory domain are limited to peptides surrounding the binding site for the amino acid substrate. These results support a model in which the N-terminus of the protein acts as an inhibitory peptide, with phenylalanine binding causing a conformational change in the regulatory domain that alters the interaction between the catalytic and regulatory domains.
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Affiliation(s)
- Jun Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station,Texas 77843-2128, USA
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Sudhakumari CC, Senthilkumaran B, Raghuveer K, Wang DS, Kobayashi T, Kagawa H, Krishnaiah C, Dutta-Gupta A, Nagahama Y. Dimorphic expression of tryptophan hydroxylase in the brain of XX and XY Nile tilapia during early development. Gen Comp Endocrinol 2010; 166:320-9. [PMID: 19925800 DOI: 10.1016/j.ygcen.2009.11.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2009] [Revised: 10/15/2009] [Accepted: 11/10/2009] [Indexed: 12/11/2022]
Abstract
Serotonin (5-HT) is well known for modulating the release of GnRH and gonadotropin in teleosts. Reports on increased female:male ratio after the blockade of 5-HT biosynthesis proposed a role for 5-HT in brain sex differentiation. Two types of tryptophan hydroxylase (Tph), rate-limiting enzyme in the biosynthesis of 5-HT were cloned from vertebrates. In the present study, we cloned Tph from brain and evaluated its importance during early development of XX and XY Nile tilapia. Tph cloned from tilapia brain is 1888 bp in length and it encodes predicted protein of 462 amino acid residues. Tph activity of tilapia was confirmed by demonstrating the conversion of L-tryptophan to 5-hydroxy tryptophan by the recombinant protein after transient transfection of this cDNA clone in COS-7 cells. Northern blot identified single transcript around 2kb in male brain. Tissue distribution of Tph revealed high abundance in brain, kidney, liver and testis. Semi-quantitative RT-PCR revealed exclusive expression of Tph in the male brain from 5 to 20 days post hatch (dph) while in the female brain, it was from 25 dph. These results were authenticated by localization of Tph transcripts in olfactory bulb-telencephalon region of 11 dph male brain using in situ hybridization. Tph immunoreactivity (-ir) was also evident in the nucleus preopticus-periventricularis area of male brain as early as 12 dph. However, Tph-ir was observed in several regions of both male and female brain without any distinction from 30 dph. Dimorphic expression pattern of Tph during early brain development around the critical period (7-21 dph) of gonadal sex determination and differentiation may implicate a role for Tph in brain sex differentiation of tilapia.
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Affiliation(s)
- C C Sudhakumari
- Department of Animal Sciences, School of Life Sciences-Centre of Advanced Study, University of Hyderabad, P.O. Central University, Hyderabad 500046, Andhra Pradesh, India.
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Hasegawa H, Nakamura K. Tryptophan Hydroxylase and Serotonin Synthesis Regulation. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2010. [DOI: 10.1016/s1569-7339(10)70078-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Haahr LT, Jensen KP, Boesen J, Christensen HEM. Experimentally calibrated computational chemistry of tryptophan hydroxylase: trans influence, hydrogen-bonding, and 18-electron rule govern O2-activation. J Inorg Biochem 2009; 104:136-45. [PMID: 19939457 DOI: 10.1016/j.jinorgbio.2009.10.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 10/09/2009] [Accepted: 10/16/2009] [Indexed: 10/20/2022]
Abstract
Insight into the nature of oxygen activation in tryptophan hydroxylase has been obtained from density functional computations. Conformations of O(2)-bound intermediates have been studied with oxygen trans to glutamate and histidine, respectively. An O(2)-adduct with O(2)trans to histidine (O(his)) and a peroxo intermediate with peroxide trans to glutamate (P(glu)) were found to be consistent (0.57-0.59mm/s) with experimental Mössbauer isomer shifts (0.55mm/s) and had low computed free energies. The weaker trans influence of histidine is shown to give rise to a bent O(2) coordination mode with O(2) pointing towards the cofactor and a more activated O-O bond (1.33A) than in O(glu) (1.30A). It is shown that the cofactor can hydrogen bond to O(2) and activate the O-O bond further (from 1.33 to 1.38A). The O(his) intermediate leads to a ferryl intermediate (F(his)) with an isomer shift of 0.34mm/s, also consistent with the experimental value (0.25mm/s) which we propose as the structure of the hydroxylating intermediate, with the tryptophan substrate well located for further reaction 3.5A from the ferryl group. Based on the optimized transition states, the activation barriers for the two paths (glu and his) are similar, so a two-state scenario involving O(his) and P(glu) is possible. A structure of the activated deoxy state which is high-spin implies that the valence electron count has been lowered from 18 to 16 (glutamate becomes bidentate), giving a "green light" that invites O(2)-binding. Our mechanism of oxygen activation in tryptophan hydroxylase does not require inversion of spin, which may be an important observation.
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Affiliation(s)
- Laerke T Haahr
- Technical University of Denmark, DTU Chemistry, Kemitorvet 207, 2800 Kgs. Lyngby, DK, Denmark
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Wang S, Sura GR, Dangott LJ, Fitzpatrick PF. Identification by hydrogen/deuterium exchange of structural changes in tyrosine hydroxylase associated with regulation. Biochemistry 2009; 48:4972-9. [PMID: 19371093 PMCID: PMC2730116 DOI: 10.1021/bi9004254] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The activity of tyrosine hydroxylase is regulated by reversible phosphorylation of serine residues in an N-terminal regulatory domain and catecholamine inhibition at the active site. Catecholamines such as dopamine bind very tightly to the resting enzyme; phosphorylation of Ser40 decreases the affinity for catecholamines by 3 orders of magnitude. The effects of dopamine binding and phosphorylation of Ser40 on the kinetics of deuterium incorporation into peptide bonds were examined by mass spectrometry. When dopamine is bound, three peptic peptides show significantly slower deuterium incorporation, 35-41 and 42-71 in the regulatory domain and 295-299 in the catalytic domain. In the phosphorylated enzyme, peptide 295-299 shows more rapid incorporation of deuterium, while 35-41 and 42-71 can not be detected. These results are consistent with tyrosine hydroxylase existing in two different conformations. In the closed conformation, the regulatory domain lies across the active site loop containing residues 295-298; this is stabilized when dopamine is bound in the active site. In the open conformation, the regulatory domain has moved out of the active site, allowing substrate access; this conformation is favored by phosphorylation of Ser40.
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Affiliation(s)
- Shanzhi Wang
- Departments of Biochemistry and Biophysics Texas A&M University, College Station TX 77843-2128
| | - Giri R. Sura
- Departments of Biochemistry and Biophysics Texas A&M University, College Station TX 77843-2128
| | - Lawrence J. Dangott
- Protein Chemistry Laboratory Texas A&M University, College Station TX 77843-2128
| | - Paul F. Fitzpatrick
- Departments of Biochemistry and Biophysics Texas A&M University, College Station TX 77843-2128
- Department of Chemistry Texas A&M University, College Station TX 77843-2128
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Meneghelli C, Rocha NH, Mengatto V, Hoeller AA, Santos TS, Lino-de-Oliveira C, Marino-Neto J. Distribution of tryptophan hydroxylase-immunoreactive neurons in the brainstem and diencephalon of the pigeon (Columba livia). J Chem Neuroanat 2009; 38:34-46. [PMID: 19559984 DOI: 10.1016/j.jchemneu.2009.03.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2008] [Revised: 02/05/2009] [Accepted: 03/29/2009] [Indexed: 11/16/2022]
Abstract
The distribution of tryptophan hydroxylase (TPH)-containing perikarya and processes in the brainstem and diencephalon of the pigeon (Columba livia) were investigated using single-labeling chromogenic and double-labeling fluorescence immunohistochemical methods for TPH and 5-HT. TPH-immunoreactive (TPH-ir) perikarya were seen extending from the caudal medulla to mid-hypothalamic levels, located in brainstem regions previously described as containing 5-HT-ir somata. Brainstem TPH-ir cell clusters (the midline raphe, and the dorsolateral and ventrolateral serotonergic cell groups) and the circumventricular cerebrospinal fluid-contacting neurons in the taenia choroidea (in the caudal brainstem), recessus infundibuli and paraventricular organ (in the hypothalamus) were shown to co-express 5-HT immunoreactivity. However, heavily labeled TPH-ir cell clusters were observed in the nucleus premamillaris (PMM), in the stratum cellulare internum (SCI), in the nucleus paraventricularis magnocellularis (PVN) and in the medial border of the nucleus dorsomedialis anterior thalami (DMA). Double-labeling experiments indicated that none of these medial hypothalamic TPH-ir cells were immunoreactive to 5-HT. These cells correspond to dopamine- and melatonin-containing neurons previously found in the avian hypothalamus, and appear to be comparable to the mammalian TPH-ir hypothalamic A11-A13 catecholaminergic somata, suggesting that they may be a conserved attribute in the amniote medial hypothalamus.
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Affiliation(s)
- Cristiane Meneghelli
- Department of Physiological Sciences, CCB, Federal University of Santa Catarina, 88049-900 Florianópolis SC, Brazil
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Siltberg-Liberles J, Steen IH, Svebak RM, Martinez A. The phylogeny of the aromatic amino acid hydroxylases revisited by characterizing phenylalanine hydroxylase from Dictyostelium discoideum. Gene 2008; 427:86-92. [DOI: 10.1016/j.gene.2008.09.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2008] [Revised: 08/28/2008] [Accepted: 09/01/2008] [Indexed: 10/21/2022]
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Huang Z, Liu T, Chattoraj A, Ahmed S, Wang MM, Deng J, Sun X, Borjigin J. Posttranslational regulation of TPH1 is responsible for the nightly surge of 5-HT output in the rat pineal gland. J Pineal Res 2008; 45:506-14. [PMID: 18705647 PMCID: PMC2669754 DOI: 10.1111/j.1600-079x.2008.00627.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT), a precursor for melatonin production, is produced abundantly in the pineal gland of all vertebrate animals. The synthesis of 5-HT in the pineal gland is rate limited by tryptophan hydroxylase 1 (TPH1) whose activity displays a twofold increase at night. Earlier studies from our laboratory demonstrate that pineal 5-HT secretion exhibits dynamic circadian rhythms with elevated levels during the early night, and that the increase is controlled by adrenergic signaling at night. In this study, we report that (a) 5-HT total output from the pineal gland and TPH1 protein levels both display diurnal rhythms with a twofold increase at night; (b) stimulation of cAMP signaling elevates 5-HT output in vivo; (c) 5-HT total output and TPH1 protein content in rat pineal gland are both acutely inhibited by light exposure at night. Consistent with these findings, molecular analysis of TPH1 protein revealed that (a) TPH1 is phosphorylated at the serine 58 in vitro and in the night pineal gland; and (b) phosphorylation of TPH1 at this residue is required for cAMP-enhanced TPH1 protein stability. These data support the model that increased nocturnal 5-HT synthesis in the pineal gland is mediated by the phosphorylation of TPH1 at the serine 58, which elevates the TPH1 protein content and activity at night.
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Affiliation(s)
- Zheping Huang
- Department of Molecular and Integrative Physiology; University of Michigan Medical School, Ann Arbor, MI, USA
| | - Tiecheng Liu
- Department of Molecular and Integrative Physiology; University of Michigan Medical School, Ann Arbor, MI, USA
| | - Asamanja Chattoraj
- Department of Molecular and Integrative Physiology; University of Michigan Medical School, Ann Arbor, MI, USA
| | - Samreen Ahmed
- Department of Molecular and Integrative Physiology; University of Michigan Medical School, Ann Arbor, MI, USA
| | - Michael M. Wang
- Department of Molecular and Integrative Physiology; University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jie Deng
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Xing Sun
- Department of Surgery, Shanghai Pudong New Area People's Hospital, Shanghai, China
| | - Jimo Borjigin
- Department of Molecular and Integrative Physiology; University of Michigan Medical School, Ann Arbor, MI, USA
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Molecular cloning, characterization and expression of two tryptophan hydroxylase (TPH-1 and TPH-2) genes in the hypothalamus of Atlantic croaker: down-regulation after chronic exposure to hypoxia. Neuroscience 2008; 158:751-65. [PMID: 19015006 DOI: 10.1016/j.neuroscience.2008.10.029] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Revised: 09/02/2008] [Accepted: 10/10/2008] [Indexed: 11/20/2022]
Abstract
Recently we discovered that hypoxia causes marked impairment of reproductive neuroendocrine function in Atlantic croaker, a marine teleost, which is due to a decline in hypothalamic serotonergic activity. As a first step in understanding the molecular responses of the hypothalamic serotonergic system to hypoxia, we cloned and characterized the genes for the enzymes regulating the rate-limiting step in serotonin biosynthesis, tryptophan hydroxylase (TPH-1 and TPH-2) in the croaker brain. The full-length croaker TPH-1 and TPH-2 cDNAs contain open reading frames encoding proteins with 479 and 487 amino acids, respectively, which are highly homologous to the TPH-1 (76-93%) and TPH-2 (64-92%) proteins of other vertebrates. Croaker TPH-1 and TPH-2 mRNA expression was detected throughout the brain but was greatest in the hypothalamic region. Both Northern blot analysis and real-time PCR showed that TPH-1 (transcript size approximately 2.1 kb) and TPH-2 ( approximately 1.9 kb) mRNA levels were significantly decreased in the hypothalami of croaker exposed for 2 weeks to hypoxic conditions compared with those in fish exposed to normoxic conditions. Immunohistochemistry of hypothalamic neurons with TPH antibodies showed reduced expression of TPHs in hypoxia-exposed fish compared with normoxic fish. Western blot analysis confirmed that hypoxia caused a marked decline in hypothalamic TPH protein levels, which was associated with decreases in hypothalamic TPH enzyme activity and 5-hydroxytryptophan levels. These results suggest that TPH is a major site of hypoxia-induced down-regulation of serotonergic function in croaker brains. Moreover, they provide the first evidence that hypoxia decreases the expression of TPH transcripts in vertebrate brains.
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Panay AJ, Fitzpatrick PF. Kinetic isotope effects on aromatic and benzylic hydroxylation by Chromobacterium violaceum phenylalanine hydroxylase as probes of chemical mechanism and reactivity. Biochemistry 2008; 47:11118-24. [PMID: 18817418 DOI: 10.1021/bi801295w] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Phenylalanine hydroxylase from Chromobacterium violaceum (CvPheH) is a non-heme iron monooxygenase that catalyzes the hydroxylation of phenylalanine to tyrosine. In this study, we used deuterium kinetic isotope effects to probe the chemical mechanisms of aromatic and benzylic hydroxylation to compare the reactivities of bacterial and eukaryotic aromatic amino acid hydroxylases. The (D) k cat value for the reaction of CvPheH with [(2)H 5]phenylalanine is 1.2 with 6-methyltetrahydropterin and 1.4 with 6,7-dimethyltetrahydropterin. With the mutant enzyme I234D, the (D) k cat value decreases to 0.9 with the latter pterin; this is likely to be the intrinsic effect for addition of oxygen to the amino acid. The isotope effect on the subsequent tautomerization of a dienone intermediate was determined to be 5.1 by measuring the retention of deuterium in tyrosine produced from partially deuterated phenylalanine; this large isotope effect is responsible for the normal effect on k cat. The isotope effect for hydroxylation of the methyl group of 4-CH 3-phenylalanine, obtained from the partitioning of benzylic and aromatic hydroxylation products, is 10. The temperature dependence of this isotope effect establishes the contribution of hydrogen tunneling to benzylic hydroxylation by this enzyme. The results presented here provide evidence that the reactivities of the prokaryotic and eukaryotic hydroxylases are similar and further define the reactivity of the iron center for the family of aromatic amino acid hydroxylases.
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Affiliation(s)
- Aram J Panay
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128, USA
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Li J, Fitzpatrick PF. Characterization of metal ligand mutants of phenylalanine hydroxylase: Insights into the plasticity of a 2-histidine-1-carboxylate triad. Arch Biochem Biophys 2008; 475:164-8. [PMID: 18477464 PMCID: PMC2518327 DOI: 10.1016/j.abb.2008.04.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Revised: 04/23/2008] [Accepted: 04/24/2008] [Indexed: 11/30/2022]
Abstract
The iron atom in the nonheme iron monooxygenase phenylalanine hydroxylase is bound on one face by His285, His290, and Glu330. This arrangement of metal ligands is conserved in the other aromatic amino acid hydroxylases, tyrosine hydroxylase and tryptophan hydroxylase. A similar 2-His-1-carboxylate facial triad of two histidines and an acidic residue are the ligands to the iron in other nonheme iron enzymes, including the alpha-ketoglutarate-dependent hydroxylases and the extradiol dioxygenases. Previous studies of the effects of conservative mutations of the iron ligands in tyrosine hydroxylase established that there is some plasticity in the nature of the ligands and that the three ligands differ in their sensitivity to mutagenesis. To determine the generality of this finding for enzymes containing a 2-His-1-carboxylate facial triad, the His285, His290, and Glu330 in rat phenylalanine hydroxylase were mutated to glutamine, glutamate, and histidine. All of the mutant proteins had low but measurable activities for tyrosine formation. In general, mutation of Glu330 had the greatest effect on activity and mutation of His290 the least. All of the mutations resulted in an excess of tetrahydropterin oxidized relative to tyrosine formation, with mutation of His285 having the greatest effect on the coupling of the two partial reactions. The H285Q enzyme had the highest activity as tetrahydropterin oxidase at 20% the wild-type value. All of the mutations greatly decreased the affinity for iron, with mutation of Glu330 the most deleterious. The results complement previous results with tyrosine hydroxylase in establishing the plasticity of the individual iron ligands in this enzyme family.
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Affiliation(s)
- Jun Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128
| | - Paul F. Fitzpatrick
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128
- Department of Chemistry, Texas A&M University, College Station, TX 77843-2128
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Immunohistochemical evidence for the presence of tryptophan hydroxylase in the brains of insects as revealed by sheep anti-tryptophan hydroxylase polyclonal antibody. Cell Tissue Res 2008; 332:555-63. [DOI: 10.1007/s00441-008-0596-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Accepted: 01/28/2008] [Indexed: 10/22/2022]
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34
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Kulikov AV, Osipova DV, Popova NK. The C1473G polymorphism in gene tph2 is the main factor mediating the genetically defined variability of tryptophan hydroxylase-2 activity in the mouse brain. RUSS J GENET+ 2007. [DOI: 10.1134/s1022795407120101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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35
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Azmitia EC. Serotonin and Brain: Evolution, Neuroplasticity, and Homeostasis. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2007; 77:31-56. [PMID: 17178471 DOI: 10.1016/s0074-7742(06)77002-7] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Efrain C Azmitia
- Department of Biology and Psychiatry, Center for Neural Science, New York University, New York 10003, USA
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36
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Hong KW, Sugawara Y, Hasegawa H, Hayasaka I, Hashimoto R, Ito S, Inoue-Murayama M. A new gain-of-function allele in chimpanzee tryptophan hydroxylase 2 and the comparison of its enzyme activity with that in humans and rats. Neurosci Lett 2006; 412:195-200. [PMID: 17123720 DOI: 10.1016/j.neulet.2006.11.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 10/05/2006] [Accepted: 11/03/2006] [Indexed: 11/26/2022]
Abstract
Tryptophan hydroxylase 2 (TPH2) is a rate-limiting enzyme of neuronal serotonin biosynthesis. Recently, two single nucleotide polymorphisms (SNPs) at the exon 11 coding region that resulted in amino acid substitutions in the C-terminal domain have been reported to affect enzyme activity in humans and mice. We determined 175 base-pair sequences of the exon 11 region in nine primate species from all recognized lineages. All nucleotide sequence substitutions were synonymous, with the exception of one adenine (A) to guanine (G) substitution at the 1404th position in the open reading frame (ORF). This substitution leads to a glutamine (Q) to arginine (R) amino acid substitution at the 468th position within chimpanzee sequences. The frequency of the G allele was 0.24 among 66 chimpanzees. Therefore, it is a novel SNP observed in chimpanzees, and we have named these two alleles as ch468Q and ch468R, respectively. When expressed in HeLa cells, ch468R caused an approximate 20% increase in enzyme function during L-5-hydroxytryptophan (5HTP) production (P<0.001). We also surveyed the interspecies difference in enzyme activity among human, chimpanzee, and rat. Although the rat showed an identical amino acid sequence at the C-terminal region as those of human and ch468Q, the rat enzyme was more active than those of human or chimpanzee (P<0.001), indicating the importance of substitutions in other regions. Our findings on the chimpanzee SNP will be a useful genetic marker in understanding the individual difference in the serotonin-related behavior.
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Affiliation(s)
- Kyung-Won Hong
- The United Graduate School of Agricultural Science, Gifu University, Gifu 501-1193, Japan
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Kaufman S. The phenylalanine hydroxylating system. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 67:77-264. [PMID: 8322620 DOI: 10.1002/9780470123133.ch2] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- S Kaufman
- Laboratory of Neurochemistry, National Institute of Mental Health, Bethesda, MD
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Wilson JE. The use of monoclonal antibodies and limited proteolysis in elucidation of structure-function relationships in proteins. METHODS OF BIOCHEMICAL ANALYSIS 2006; 35:207-50. [PMID: 2002771 DOI: 10.1002/9780470110560.ch4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- J E Wilson
- Biochemistry Department, Michigan State University, East Lansing
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Sura GR, Lasagna M, Gawandi V, Reinhart GD, Fitzpatrick PF. Effects of ligands on the mobility of an active-site loop in tyrosine hydroxylase as monitored by fluorescence anisotropy. Biochemistry 2006; 45:9632-8. [PMID: 16878998 PMCID: PMC2031214 DOI: 10.1021/bi060754b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Fluorescence anisotropy has been used to monitor the effect of ligands on a mobile loop over the active site of tyrosine hydroxylase. Phe184 in the center of the loop was mutated to tryptophan, and the three native tryptophan residues were mutated to phenylalanine to form an enzyme with a single tryptophan residue in the mobile loop. The addition of 6-methyl-5-deazatetrahydropterin to the enzyme resulted in a significant increase in the fluorescence anisotropy. The addition of phenylalanine did not result in a significant change in the anisotropy in the presence or absence of the deazapterin. The K(d) value for the deazapterin was unaffected by the presence of phenylalanine. Qualitatively similar results were obtained with apoenzyme, except that the addition of phenylalanine led to a slight decrease in anisotropy. Frequency-domain lifetime measurements showed that the distribution of lifetimes was unaffected by both the amino acid and deazapterin. Frequency-domain anisotropy analyses were consistent with a decrease in the motion of the sole tryptophan in the presence of the deazapterin. This could be modeled as a decrease in the cone angle for the indole ring of about 12 degrees . The data are consistent with a model in which binding of a tetrahydropterin results in a change in the conformation of the surface loop required for proper formation of the amino acid binding site.
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Affiliation(s)
- Giri R Sura
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128, USA
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Carkaci-Salli N, Flanagan JM, Martz MK, Salli U, Walther DJ, Bader M, Vrana KE. Functional Domains of Human Tryptophan Hydroxylase 2 (hTPH2). J Biol Chem 2006; 281:28105-12. [PMID: 16864580 DOI: 10.1074/jbc.m602817200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in serotonin biosynthesis. A novel gene, termed TPH2, has recently been described. This gene is preferentially expressed in the central nervous system, while the original TPH1 is the peripheral gene. We have expressed human tryptophan hydroxylase 2 (hTPH2) and two deletion mutants (NDelta150 and NDelta150/CDelta24) using isopropyl beta-D-thiogalactopyranoside-free autoinduction in Escherichia coli. This expression system produced active wild type TPH2 with relatively low solubility. The solubility was increased for mutants lacking the NH(2)-terminal regulatory domain. The solubility of hTPH2, NDelta150, and NDelta150/CDelta24 are 6.9, 62, and 97.5%, respectively. Removal of the regulatory domain also produced a more than 6-fold increase in enzyme stability (t((1/2)) at 37 degrees C). The wild type hTPH2, like other members of the aromatic amino acid hydroxylase superfamily, exists as a homotetramer (236 kDa on size exclusion chromatography). Similarly, NDelta150 also migrates as a tetramer (168 kDa). In contrast, removal of the NH(2)-terminal domain and the COOH-terminal, putative leucine zipper tetramerization domain produces monomeric enzyme (39 kDa). Interestingly, removal of the NH(2)-terminal regulatory domain did not affect the Michaelis constants for either substrate but did increase V(max) values. These data identify the NH(2)-terminal regulatory domain as the source of hTPH2 instability and reduced solubility.
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Affiliation(s)
- Nurgul Carkaci-Salli
- Department of Pharmacology, Penn State College of Medicine, Hershey, Pennsylvania 17033-2360, USA
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41
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Sakowski SA, Geddes TJ, Thomas DM, Levi E, Hatfield JS, Kuhn DM. Differential tissue distribution of tryptophan hydroxylase isoforms 1 and 2 as revealed with monospecific antibodies. Brain Res 2006; 1085:11-8. [PMID: 16581041 DOI: 10.1016/j.brainres.2006.02.047] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Revised: 02/07/2006] [Accepted: 02/13/2006] [Indexed: 11/15/2022]
Abstract
Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in the synthesis of the neurotransmitter serotonin. Once thought to be a single-gene product, TPH is now known to exist in two isoforms-TPH1 is found in the pineal and gut, and TPH2 is selectively expressed in brain. Heretofore, probes used for localization of TPH protein or mRNA could not distinguish between the TPH isoforms because of extensive homology shared by them at the nucleotide and amino acid level. We have produced monospecific polyclonal antibodies against TPH1 and TPH2 using peptide antigens from nonoverlapping sequences in the respective proteins. These antibodies allow the differentiation of TPH1 and TPH2 upon immunoblotting, immunoprecipitation, and immunocytochemical staining of tissue sections from brain and gut. TPH1 and TPH2 antibodies do not cross-react with either tyrosine hydroxylase or phenylalanine hydroxylase. Analysis of mouse tissues confirms that TPH1 is the predominant form expressed in pineal gland and in P815 mastocytoma cells with a molecular weight of 51 kDa. TPH2 is the predominant enzyme form expressed in brain extracts from mesencephalic tegmentum, striatum, and hippocampus with a molecular weight of 56 kDa. Antibody specificity against TPH1 and TPH2 is retained across mouse, rat, rabbit, primate, and human tissues. Antibodies that distinguish between the isoforms of TPH will allow studies of the differential regulation of their expression in brain and periphery.
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Affiliation(s)
- Stacey A Sakowski
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, USA
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Daubner SC, McGinnis JT, Gardner M, Kroboth SL, Morris AR, Fitzpatrick PF. A flexible loop in tyrosine hydroxylase controls coupling of amino acid hydroxylation to tetrahydropterin oxidation. J Mol Biol 2006; 359:299-307. [PMID: 16618490 PMCID: PMC1945210 DOI: 10.1016/j.jmb.2006.03.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2006] [Revised: 03/08/2006] [Accepted: 03/08/2006] [Indexed: 10/24/2022]
Abstract
The role of a polypeptide loop in tyrosine hydroxylase (TyrH) whose homolog in phenylalanine hydroxylase (PheH) takes on a different conformation when substrates are bound has been studied using site-directed mutagenesis. The loop spans positions 177 to 191; alanine was introduced into those positions, introducing one alanine substitution per TyrH variant. Mutagenesis of residues in the center of the loop resulted in alterations in the KM values for substrates, the Vmax value for dihydroxyphenylalanine (DOPA) synthesis, and the coupling of tetrahydropterin oxidation to tyrosine hydroxylation. The variant with the most altered KM value for 6-methyltetrahydropterin was TyrH F184A. The variants with the most affected K(tyr) values were those with substitutions in the center of the loop, TyrH K183A, F184A, D185A, P186A and D187A. These five variants also had the most reduced Vmax values for DOPA synthesis. Alanine substitution in positions 182-186 resulted in lowered ratios of tyrosine hydroxylation to tetrahydropterin oxidation. TyrH F184Y and PheH Y138F, variants with the residue at the center of the loop substituted with the residue present at the homologous position in the other hydroxylase, were also studied. The V/K(tyr) to V/K(phe) ratios for these variants were altered significantly, but the results did not suggest that F184 of TyrH or Y138 of PheH plays a dominant role in determining amino acid substrate specificity.
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Affiliation(s)
- S Colette Daubner
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128, USA
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Bao X, Tian X, Hu X, Zhao Z, Qu Y, Song C. Discovery of specific tryptophan hydroxylase in the brain of the beetle Harmonia axyridis. Brain Res 2006; 1073-1074:202-8. [PMID: 16426586 DOI: 10.1016/j.brainres.2005.12.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 12/06/2005] [Accepted: 12/06/2005] [Indexed: 11/27/2022]
Abstract
Rabbit anti-serotonin and mouse monoclonal anti-tryptophan hydroxylase antisera were applied on the brain sections of the beetle Harmonia axyridis, butterfly Childrena zenobia, moth Antheraea pernyi and ant Camponotus japonicus, using the Streptavidin-Peroxidase immunohistochemical method and Colophony-Paraffin embedded section technique. Results revealed that all the experimental insects showed notable serotonin-like immunoreactivity in the brain. However, only the brain sections of the beetle H. axyridis were strongly labeled by mouse monoclonal anti-tryptophan hydroxylase antiserum, with the distribution pattern matching that of serotonin. These results demonstrate that specific tryptophan hydroxylase may exist in the brain of the beetle and likely reflect the diversity of serotonin synthetic mechanisms as well as the evolution of aromatic amino acid hydroxylase genes.
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Affiliation(s)
- Xuexiang Bao
- Laboratory of Insect Brain Neurobiology, School of Life Sciences, Northeast Normal University, Changchun 130024, P.R. China.
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Sakowski SA, Geddes TJ, Kuhn DM. Mouse tryptophan hydroxylase isoform 2 and the role of proline 447 in enzyme function. J Neurochem 2006; 96:758-65. [PMID: 16405505 DOI: 10.1111/j.1471-4159.2005.03604.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in the synthesis of the neurotransmitter serotonin (5-HT). Once thought to be a single gene product, TPH is now known to exist in two isoforms. Isoform 1 (TPH1) is found in the pineal gland and gut, and isoform 2 (TPH2) is selectively expressed in brain. A single-nucleotide polymorphism in TPH2 results in a proline-to-arginine mutation at residue 447 and substantially lowers catalytic activity. In view of the importance of TPH in determining brain 5-HT function, we cloned TPH2 and produced the P447R mutant to assess the importance of this proline in enzyme function. Catalytically active TPH2 and the P447R mutant were expressed at the predicted subunit molecular mass of 56 kDa. The P447R mutant expressed less than 50% of the activity of TPH2. Mutation of this conserved proline in TPH1 (P403R) also resulted in an enzyme with significantly lower activity than the wild-type enzyme. The P447R mutant had a V(max) 50% lower than that of TPH2. The P447R mutation did not alter the oligomeric assembly of the protein, nor change its responsiveness to cysteine modification. The P447R mutation did not alter enzyme substrate specificity or stability, but conferred slightly enhanced sensitivity to inhibition by dopamine and diminished sensitivity to iron in catalysis. The conserved proline in TPH (residue 447 in TPH2 and 403 in TPH1) plays an important role in enzyme function by regulating V(max) of the catalytic reaction.
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Affiliation(s)
- Stacey A Sakowski
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, USA
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45
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Sura GR, Daubner SC, Fitzpatrick PF. Effects of phosphorylation by protein kinase A on binding of catecholamines to the human tyrosine hydroxylase isoforms. J Neurochem 2004; 90:970-8. [PMID: 15287903 PMCID: PMC1839072 DOI: 10.1111/j.1471-4159.2004.02566.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tyrosine hydroxylase (TyrH), the catalyst for the key regulatory step in catecholamine biosynthesis, is phosphorylated by cAMP-dependent protein kinase A (PKA) on a serine residue in a regulatory domain. In the case of the rat enzyme, phosphorylation of Ser40 by PKA is critical in regulating the enzyme activity; the effect of phosphorylation is to relieve the enzyme from inhibition by dopamine and dihydroxyphenylalanine (DOPA). There are four isoforms of human tyrosine hydroxylase (hTyrH), differing in the size of an insertion after Met30. The effects of phosphorylation by PKA on the binding of DOPA and dopamine have now been determined for all four human isoforms. There is an increase of about two-fold in the Kd value for DOPA for isoform 1 upon phosphorylation, from 4.4 to 7.4 microM; this effect decreases with the larger isoforms such that there is no effect of phosphorylation on the Kd value for isoform 4. Dopamine binds more much tightly, with Kd values less than 3 nM for all four unphosphorylated isoforms. Phosphorylation decreases the affinity for dopamine at least two orders of magnitude, resulting in Kd values of about 0.1 microM for the phosphorylated human enzymes, due primarily to increases in the rate constant for dissociation of dopamine. Dopamine binds about two-fold less tightly to the phosphorylated isoform 1 than to the other three isoforms. The results extend the regulatory model developed for the rat enzyme, in which the activity is regulated by the opposing effects of catecholamine binding and phosphorylation by PKA. The small effects on the relatively high Kd values for DOPA suggest that DOPA levels do not regulate the activity of hTyrH.
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Affiliation(s)
- Giri R Sura
- Department of Biochemistry and Biophysics, Texas A & M University, College Station, Texas 77843-2128, USA
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46
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Shiota Y, Yoshizawa K. QM/MM Study of the Mononuclear Non-Heme Iron Active Site of Phenylalanine Hydroxylase. J Phys Chem B 2004. [DOI: 10.1021/jp048001r] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Yoshihito Shiota
- Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka 812-8581, Japan
| | - Kazunari Yoshizawa
- Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka 812-8581, Japan
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47
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Coleman CM, Neckameyer WS. Substrate regulation of serotonin and dopamine synthesis in Drosophila. INVERTEBRATE NEUROSCIENCE : IN 2004; 5:85-96. [PMID: 15480914 DOI: 10.1007/s10158-004-0031-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/11/2004] [Indexed: 11/24/2022]
Abstract
In Drosophila melanogaster, serotonin (5-hydroxytryptamine, 5-HT) is required for both very early non-neuronal developmental events, and in the CNS as a neurotransmitter to modulate behavior. 5-HT is synthesized, at least in part, by the actions of Drosophila tryptophan-phenylalanine hydroxylase (DTPH), a dual function enzyme that hydroxylates both phenylalanine and tryptophan. DTPH is expressed in numerous tissues as well as dopaminergic and serotonergic neurons, but it does not necessarily function as both enzymes in these tissues. Deficiencies in DTPH could affect the production of dopamine and serotonin, and thus dopaminergic and serotonergic signaling pathways. In this paper, we show that DTPH exhibits differential hydroxylase activity based solely on substrate. When DTPH uses phenylalanine as a substrate, regulatory control (end product inhibition, decreased PAH activity following phosphorylation, catecholamine inhibition) is observed that is not seen when the enzyme uses tryptophan as a substrate. These studies suggest that regulation of DTPH enzymatic activity occurs, at least in part, through the actions of its substrate.
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Affiliation(s)
- Chandra M Coleman
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, 1402 S. Grand Blvd, St. Louis, MO 63104, USA
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48
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Affiliation(s)
- Paul F Fitzpatrick
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, USA.
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49
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Abstract
Serotonin (5-hydroxytryptophan, 5-HT) is a neurotransmitter synthesized in the raphe nuclei of the brain stem and involved in the central control of food intake, sleep, and mood. Accordingly, dysfunction of the serotonin system has been implicated in the pathogenesis of psychiatric diseases. At the same time, serotonin is a peripheral hormone produced mainly by enterochromaffin cells in the intestine and stored in platelets, where it is involved in vasoconstriction, haemostasis, and the control of immune responses. Moreover, serotonin is a precursor for melatonin and is therefore synthesized in high amounts in the pineal gland. Tryptophan hydroxylase (TPH) catalyzes the rate limiting step in 5-HT synthesis. Until recently, only one gene encoding TPH was described for vertebrates. By gene targeting, we functionally ablated this gene in mice. To our surprise, the resulting animals, although being deficient for serotonin in the periphery and in the pineal gland, exhibited close to normal levels of 5-HT in the brain stem. This led us to the detection of a second TPH gene in the genome of humans, mice, and rats, called TPH2. This gene is predominantly expressed in the brain stem, while the classical TPH gene, now called TPH1, is expressed in the gut, pineal gland, spleen, and thymus. These findings clarify puzzling data, which have been collected over the last decades about partially purified TPH proteins with different characteristics and justify a new concept of the serotonin system. In fact, there are two serotonin systems in vertebrates, independently regulated and with distinct functions.
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Affiliation(s)
- Diego J Walther
- Max Delbrück Center for Molecular Medicine (MDC), Robert-Rossle-Strasse 10, D-13092 Berlin-Buch, Germany
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50
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Yohrling GJ, Jiang GCT, DeJohn MM, Miller DW, Young AB, Vrana KE, Cha JHJ. Analysis of cellular, transgenic and human models of Huntington's disease reveals tyrosine hydroxylase alterations and substantia nigra neuropathology. ACTA ACUST UNITED AC 2003; 119:28-36. [PMID: 14597227 DOI: 10.1016/j.molbrainres.2003.08.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Huntington's disease (HD) is a progressive, autosomal dominant neurodegenerative disorder that is pathologically characterized by a striatal-specific degeneration. Aberrant dopamine neurotransmission has been proposed as a mechanism underlying the movement disorder of HD. We report that the enzymatic activity of tyrosine hydroxylase (TH), the rate-limiting enzyme for dopamine biosynthesis, is decreased in a transgenic mouse model of HD. In addition, mutant huntingtin was found to disrupt transcription of TH and dopamine beta-hydroxylase (DbetaH) promoter reporter constructs. In situ hybridization revealed extensive loss of TH mRNA and decreased dopaminergic cell size in human HD substantia nigra. TH-immunoreactive protein was reduced in human grade 4 HD substantia nigra by 32% compared to age-matched controls. These findings implicate abnormalities in dopamine neurotransmission in HD and may provide new insights into targets for pharmacotherapy.
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Affiliation(s)
- George J Yohrling
- Department of Neurology, Center for Aging, Genetics, and Neurodegeneration, Massachusetts General Hospital, 114 16th Street, B114-2000, Charlestown, MA 02129-4404, USA
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