1
|
Myo-D-inositol Trisphosphate Signalling in Oomycetes. Microorganisms 2022; 10:microorganisms10112157. [DOI: 10.3390/microorganisms10112157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 10/21/2022] [Accepted: 10/27/2022] [Indexed: 11/06/2022] Open
Abstract
Oomycetes are pathogens of plants and animals, which cause billions of dollars of global losses to the agriculture, aquaculture and forestry sectors each year. These organisms superficially resemble fungi, with an archetype being Phytophthora infestans, the cause of late blight of tomatoes and potatoes. Comparison of the physiology of oomycetes with that of other organisms, such as plants and animals, may provide new routes to selectively combat these pathogens. In most eukaryotes, myo-inositol 1,4,5 trisphosphate is a key second messenger that links extracellular stimuli to increases in cytoplasmic Ca2+, to regulate cellular activities. In the work presented in this study, investigation of the molecular components of myo-inositol 1,4,5 trisphosphate signaling in oomycetes has unveiled similarities and differences with that in other eukaryotes. Most striking is that several oomycete species lack detectable phosphoinositide-selective phospholipase C homologues, the enzyme family that generates this second messenger, but still possess relatives of myo-inositol 1,4,5 trisphosphate-gated Ca2+-channels.
Collapse
|
2
|
Insights to the Structural Basis for the Stereospecificity of the Escherichia coli Phytase, AppA. Int J Mol Sci 2022; 23:ijms23116346. [PMID: 35683026 PMCID: PMC9181005 DOI: 10.3390/ijms23116346] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 05/30/2022] [Accepted: 06/02/2022] [Indexed: 02/01/2023] Open
Abstract
AppA, the Escherichia coli periplasmic phytase of clade 2 of the histidine phosphatase (HP2) family, has been well-characterized and successfully engineered for use as an animal feed supplement. AppA is a 1D-6-phytase and highly stereospecific but transiently accumulates 1D-myo-Ins(2,3,4,5)P4 and other lower phosphorylated intermediates. If this bottleneck in liberation of orthophosphate is to be obviated through protein engineering, an explanation of its rather rigid preference for the initial site and subsequent cleavage of phytic acid is required. To help explain this behaviour, the role of the catalytic proton donor residue in determining AppA stereospecificity was investigated. Four variants were generated by site-directed mutagenesis of the active site HDT amino acid sequence motif containing the catalytic proton donor, D304. The identity and position of the prospective proton donor residue was found to strongly influence stereospecificity. While the wild-type enzyme has a strong preference for 1D-6-phytase activity, a marked reduction in stereospecificity was observed for a D304E variant, while a proton donor-less mutant (D304A) displayed exclusive 1D-1/3-phytase activity. High-resolution X-ray crystal structures of complexes of the mutants with a non-hydrolysable substrate analogue inhibitor point to a crucial role played by D304 in stereospecificity by influencing the size and polarity of specificity pockets A and B. Taken together, these results provide the first evidence for the involvement of the proton donor residue in determining the stereospecificity of HP2 phytases and prepares the ground for structure-informed engineering studies targeting the production of animal feed enzymes capable of the efficient and complete dephosphorylation of dietary phytic acid.
Collapse
|
3
|
Zubair M, Hamzah R, Griffin R, Ali N. Identification and functional characterization of multiple inositol polyphosphate phosphatase1 (Minpp1) isoform-2 in exosomes with potential to modulate tumor microenvironment. PLoS One 2022; 17:e0264451. [PMID: 35235602 PMCID: PMC8890658 DOI: 10.1371/journal.pone.0264451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 02/10/2022] [Indexed: 01/06/2023] Open
Abstract
Inositol polyphosphates (InsPs) play key signaling roles in diverse cellular functions, including calcium homeostasis, cell survival and death. Multiple inositol polyphosphate phosphatase 1 (Minpp1) affects the cellular levels of InsPs and cell functions. The Minpp1 is an endoplasmic reticulum (ER) resident but localizes away from its cytosolic InsPs substrates. The current study examines the heterogeneity of Minpp1 and the potential physiologic impact of Minpp1 isoforms, distinct motifs, subcellular distribution, and enzymatic potential. The NCBI database was used to analyze the proteome diversity of Minpp1 using bioinformatics tools. The analysis revealed that translation of three different Minpp1 variants resulted in three isoforms of Minpp1 of varying molecular weights. A link between the minpp1 variant-2 gene and ER-stress, using real-time PCR, suggests a functional similarity between minpp1 variant-1 and variant-2. A detailed study on motifs revealed Minpp1 isoform-2 is the only other isoform, besides isoform-1, that carries a phosphatase motif for InsPs hydrolysis but no ER-retention signal. The confocal microscopy revealed that the Minpp1 isoform-1 predominantly localized near the nucleus with a GRP-78 ER marker, while Minpp1 isoform-2 was scattered more towards the cell periphery where it co-localizes with the plasma membrane-destined multivesicular bodies biomarker CD63. MCF-7 cells were used to establish that Minpp1 isoform-2 is secreted into exosomes. Brefeldin A treatment resulted in overexpression of the exosome-associated Minpp1 isoform-2, suggesting its secretion via an unconventional route involving endocytic-generated vesicles and a link to ER stress. Results further demonstrated that the exosome-associated Minpp1 isoform-2 was enzymatically active. Overall, the data support the possibility that an extracellular form of enzymatically active Minpp1 isoform-2 mitigates any anti-proliferative actions of extracellular InsPs, thereby also impacting the makeup of the tumor microenvironment.
Collapse
Affiliation(s)
- Mohd Zubair
- Department of Biology, University of Arkansas at Little Rock, Little Rock, AR, United States of America
| | - Rabab Hamzah
- Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AR, United States of America
- Center for Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, Little Rock, AR, United States of America
| | - Robert Griffin
- Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AR, United States of America
| | - Nawab Ali
- Department of Biology, University of Arkansas at Little Rock, Little Rock, AR, United States of America
| |
Collapse
|
4
|
Ricaña CL, Dick RA. Inositol Phosphates and Retroviral Assembly: A Cellular Perspective. Viruses 2021; 13:v13122516. [PMID: 34960784 PMCID: PMC8703376 DOI: 10.3390/v13122516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/09/2021] [Accepted: 12/11/2021] [Indexed: 12/13/2022] Open
Abstract
Understanding the molecular mechanisms of retroviral assembly has been a decades-long endeavor. With the recent discovery of inositol hexakisphosphate (IP6) acting as an assembly co-factor for human immunodeficiency virus (HIV), great strides have been made in retroviral research. In this review, the enzymatic pathways to synthesize and metabolize inositol phosphates (IPs) relevant to retroviral assembly are discussed. The functions of these enzymes and IPs are outlined in the context of the cellular biology important for retroviruses. Lastly, the recent advances in understanding the role of IPs in retroviral biology are surveyed.
Collapse
|
5
|
Nakajima T, Hosoyamada S, Kobayashi T, Mukai Y. Secreted acid phosphatases maintain replicative lifespan via inositol polyphosphate metabolism in budding yeast. FEBS Lett 2021; 596:189-198. [PMID: 34845723 DOI: 10.1002/1873-3468.14245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/03/2021] [Accepted: 11/24/2021] [Indexed: 11/07/2022]
Abstract
Secreted acid phosphatases (APases) dephosphorylate extracellular organic phosphate compounds to supply inorganic phosphate (Pi) to maintain cellular functions. Here, we show that APases are necessary to maintain a normal replicative lifespan in Saccharomyces cerevisiae. Deletion of all four APase genes shortened the lifespan in yeast strains on synthetic media (irrespective of the concentrations of Pi in the media), but it did not affect the intracellular ortho- and polyphosphate levels. Deletion of inositol-pentakisphosphate 2-kinase (IPK1), which encodes inositol-pentakisphosphate 2-kinase, restored the lifespan in APase-null mutants, and IPK1 overexpression shortened the lifespan in wild-type strains. Overexpression of inositol hexakisphosphate (IP6 ) and heptakisphosphate kinases, KCS1 and VIP1, recovered the lifespan in APase-null mutants. Thus, yeast APases modulate the replicative lifespan, probably through dephosphorylation of intracellular IP6 .
Collapse
Affiliation(s)
- Toshio Nakajima
- Department of Frontier Bioscience, Nagahama Institute of Bio-Science and Technology, Shiga, Japan
| | - Shun Hosoyamada
- Institute for Quantitative Biosciences, The University of Tokyo, Japan
| | - Takehiko Kobayashi
- Institute for Quantitative Biosciences, The University of Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Japan
| | - Yukio Mukai
- Department of Frontier Bioscience, Nagahama Institute of Bio-Science and Technology, Shiga, Japan
| |
Collapse
|
6
|
Acquistapace IM, Zi Etek MA, Li AWH, Salmon M, Kühn I, Bedford MR, Brearley CA, Hemmings AM. Snapshots during the catalytic cycle of a histidine acid phytase reveal an induced-fit structural mechanism. J Biol Chem 2020; 295:17724-17737. [PMID: 33454010 PMCID: PMC7762957 DOI: 10.1074/jbc.ra120.015925] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/10/2020] [Indexed: 11/16/2022] Open
Abstract
Highly engineered phytases, which sequentially hydrolyze the hexakisphosphate ester of inositol known as phytic acid, are routinely added to the feeds of monogastric animals to improve phosphate bioavailability. New phytases are sought as starting points to further optimize the rate and extent of dephosphorylation of phytate in the animal digestive tract. Multiple inositol polyphosphate phosphatases (MINPPs) are clade 2 histidine phosphatases (HP2P) able to carry out the stepwise hydrolysis of phytate. MINPPs are not restricted by a strong positional specificity making them attractive targets for development as feed enzymes. Here, we describe the characterization of a MINPP from the Gram-positive bacterium Bifidobacterium longum (BlMINPP). BlMINPP has a typical HP2P-fold but, unusually, possesses a large α-domain polypeptide insertion relative to other MINPPs. This insertion, termed the U-loop, spans the active site and contributes to substrate specificity pockets underpopulated in other HP2Ps. Mutagenesis of U-loop residues reveals its contribution to enzyme kinetics and thermostability. Moreover, four crystal structures of the protein along the catalytic cycle capture, for the first time in an HP2P, a large ligand-driven α-domain motion essential to allow substrate access to the active site. This motion recruits residues both downstream of a molecular hinge and on the U-loop to participate in specificity subsites, and mutagenesis identified a mobile lysine residue as a key determinant of positional specificity of the enzyme. Taken together, these data provide important new insights to the factors determining stability, substrate recognition, and the structural mechanism of hydrolysis in this industrially important group of enzymes.
Collapse
Affiliation(s)
| | - Monika A Zi Etek
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Arthur W H Li
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Melissa Salmon
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | | | | | - Charles A Brearley
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Andrew M Hemmings
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom; School of Chemistry, University of East Anglia, Norwich, United Kingdom.
| |
Collapse
|
7
|
Ucuncu E, Rajamani K, Wilson MSC, Medina-Cano D, Altin N, David P, Barcia G, Lefort N, Banal C, Vasilache-Dangles MT, Pitelet G, Lorino E, Rabasse N, Bieth E, Zaki MS, Topcu M, Sonmez FM, Musaev D, Stanley V, Bole-Feysot C, Nitschké P, Munnich A, Bahi-Buisson N, Fossoud C, Giuliano F, Colleaux L, Burglen L, Gleeson JG, Boddaert N, Saiardi A, Cantagrel V. MINPP1 prevents intracellular accumulation of the chelator inositol hexakisphosphate and is mutated in Pontocerebellar Hypoplasia. Nat Commun 2020; 11:6087. [PMID: 33257696 PMCID: PMC7705663 DOI: 10.1038/s41467-020-19919-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 10/29/2020] [Indexed: 12/13/2022] Open
Abstract
Inositol polyphosphates are vital metabolic and secondary messengers, involved in diverse cellular functions. Therefore, tight regulation of inositol polyphosphate metabolism is essential for proper cell physiology. Here, we describe an early-onset neurodegenerative syndrome caused by loss-of-function mutations in the multiple inositol-polyphosphate phosphatase 1 gene (MINPP1). Patients are found to have a distinct type of Pontocerebellar Hypoplasia with typical basal ganglia involvement on neuroimaging. We find that patient-derived and genome edited MINPP1−/− induced stem cells exhibit an inefficient neuronal differentiation combined with an increased cell death. MINPP1 deficiency results in an intracellular imbalance of the inositol polyphosphate metabolism. This metabolic defect is characterized by an accumulation of highly phosphorylated inositols, mostly inositol hexakisphosphate (IP6), detected in HEK293 cells, fibroblasts, iPSCs and differentiating neurons lacking MINPP1. In mutant cells, higher IP6 level is expected to be associated with an increased chelation of intracellular cations, such as iron or calcium, resulting in decreased levels of available ions. These data suggest the involvement of IP6-mediated chelation on Pontocerebellar Hypoplasia disease pathology and thereby highlight the critical role of MINPP1 in the regulation of human brain development and homeostasis. Tight regulation of inositol polyphosphate metabolism is essential for proper cell physiology. Here, the authors describe an early-onset neurodegenerative syndrome caused by loss-of-function mutations in the MINPP1 gene, characterised by intracellular imbalance of inositol polyphosphate metabolism.
Collapse
Affiliation(s)
- Ekin Ucuncu
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Karthyayani Rajamani
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Miranda S C Wilson
- MRC Laboratory for Molecular Cell Biology, University College London, WC1E 6BT, London, UK
| | - Daniel Medina-Cano
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Nami Altin
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Pierre David
- Transgenesis Platform, Laboratoire d'Expérimentation Animale et Transgenèse (LEAT), Imagine Institute, Structure Fédérative de Recherche Necker INSERM US24/CNRS UMS3633, 75015, Paris, France
| | - Giulia Barcia
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France.,Département de Génétique Médicale, AP-HP, Hôpital Necker-Enfants Malades, F-75015, Paris, France
| | - Nathalie Lefort
- Université de Paris, iPSC Core Facility, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Céline Banal
- Université de Paris, iPSC Core Facility, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | | | - Gaële Pitelet
- Service de Neuropédiatrie, CHU Nice, 06200, Nice, France
| | - Elsa Lorino
- ESEAN, 44200 Nantes, Service de maladies chroniques de l'enfant, CHU Nantes, 44093, Nantes, France
| | - Nathalie Rabasse
- Service de pédiatrie, hôpital d'Antibes-Juan-les-Pins, 06600, Antibes-Juan-les-Pins, France
| | - Eric Bieth
- Service de Génétique Médicale, CHU Toulouse, 31059, Toulouse, France
| | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, 12311, Egypt
| | - Meral Topcu
- Department of Child Neurology, Faculty of Medicine, Hacettepe University, Ankara, 06100, Turkey
| | - Fatma Mujgan Sonmez
- Guven Hospital, Child Neurology Department, Ankara, Turkey.,Department of Child Neurology, Faculty of Medicine, Karadeniz Technical University, Trabzon, 61080, Turkey
| | - Damir Musaev
- Laboratory for Pediatric Brain Diseases, Rady Children's Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Valentina Stanley
- Laboratory for Pediatric Brain Diseases, Rady Children's Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Christine Bole-Feysot
- Université de Paris, Genomics Platform, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Patrick Nitschké
- Université de Paris, Bioinformatics Core Facility, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Arnold Munnich
- Université de Paris, Translational Genetics Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Nadia Bahi-Buisson
- Université de Paris, Genetics and Development of the Cerebral Cortex Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Catherine Fossoud
- Centre de Référence des Troubles des Apprentissages, Hôpitaux Pédiatriques de Nice CHU-Lenval, 06200, Nice, France
| | - Fabienne Giuliano
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Nice, 06202, Nice, France
| | - Laurence Colleaux
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Lydie Burglen
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France.,Centre de Référence des Malformations et Maladies Congénitales du Cervelet, Département de Génétique, AP-HP, Sorbonne Université, Hôpital Trousseau, 75012, Paris, France
| | - Joseph G Gleeson
- Laboratory for Pediatric Brain Diseases, Rady Children's Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Nathalie Boddaert
- Département de radiologie pédiatrique, INSERM UMR 1163 and INSERM U1000, AP-HP, Hôpital Necker-Enfants Malades, F-75015, Paris, France
| | - Adolfo Saiardi
- MRC Laboratory for Molecular Cell Biology, University College London, WC1E 6BT, London, UK.
| | - Vincent Cantagrel
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France.
| |
Collapse
|
8
|
Appelhof B, Wagner M, Hoefele J, Heinze A, Roser T, Koch-Hogrebe M, Roosendaal SD, Dehghani M, Mehrjardi MYV, Torti E, Houlden H, Maroofian R, Rajabi F, Sticht H, Baas F, Wieczorek D, Jamra RA. Pontocerebellar hypoplasia due to bi-allelic variants in MINPP1. Eur J Hum Genet 2020; 29:411-421. [PMID: 33168985 PMCID: PMC7940488 DOI: 10.1038/s41431-020-00749-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 09/11/2020] [Accepted: 09/22/2020] [Indexed: 12/24/2022] Open
Abstract
Pontocerebellar hypoplasia (PCH) describes a group of rare heterogeneous neurodegenerative diseases with prenatal onset. Here we describe eight children with PCH from four unrelated families harboring the homozygous MINPP1 (NM_004897.4) variants; c.75_94del, p.(Leu27Argfs*39), c.851 C > A, p.(Ala284Asp), c.1210 C > T, p.(Arg404*), and c.992 T > G, p.(Ile331Ser). The homozygous p.(Leu27Argfs*39) change is predicted to result in a complete absence of MINPP1. The p.(Arg404*) would likely lead to a nonsense mediated decay, or alternatively, a loss of several secondary structure elements impairing protein folding. The missense p.(Ala284Asp) affects a buried, hydrophobic residue within the globular domain. The introduction of aspartic acid is energetically highly unfavorable and therefore predicted to cause a significant reduction in protein stability. The missense p.(Ile331Ser) affects the tight hydrophobic interactions of the isoleucine by the disruption of the polar side chain of serine, destabilizing the structure of MINPP1. The overlap of the above-mentioned genotypes and phenotypes is highly improbable by chance. MINPP1 is the only enzyme that hydrolyses inositol phosphates in the endoplasmic reticulum lumen and several studies support its role in stress induced apoptosis. The pathomechanism explaining the disease mechanism remains unknown, however several others genes of the inositol phosphatase metabolism (e.g., INPP5K, FIG4, INPP5E, ITPR1) are correlated with phenotypes of neurodevelopmental disorders. Taken together, we present MINPP1 as a novel autosomal recessive pontocerebellar hypoplasia gene.
Collapse
Affiliation(s)
- Bart Appelhof
- Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands
| | - Matias Wagner
- Institute of Neurogenomics, Helmholtz Zentrum Munich, Neuherberg, Germany, Technical University of Munich, Munich, Germany.,Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Julia Hoefele
- Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Anja Heinze
- Institute of Human Genetics, University Medical Center Leipzig, Leipzig, Germany
| | - Timo Roser
- Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, Department of Pediatrics, Dr. von Haunersches Children's Hospital, Ludwig-Maximilian-University of Munich, Munich, Germany
| | | | - Stefan D Roosendaal
- Department of Radiology, Amsterdam University Medical Centers, Amsterdam, Netherlands
| | - Mohammadreza Dehghani
- Medical Genetics Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | | | | | - Henry Houlden
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK
| | - Reza Maroofian
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK
| | - Farrah Rajabi
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachussetts, USA
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander -Nürnberg, Erlangen, Germany
| | - Frank Baas
- Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands.
| | - Dagmar Wieczorek
- Institute of Human Genetics, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Rami Abou Jamra
- Institute of Human Genetics, University Medical Center Leipzig, Leipzig, Germany.
| |
Collapse
|
9
|
Madsen CK, Brinch-Pedersen H. Globoids and Phytase: The Mineral Storage and Release System in Seeds. Int J Mol Sci 2020; 21:ijms21207519. [PMID: 33053867 PMCID: PMC7589363 DOI: 10.3390/ijms21207519] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 10/07/2020] [Accepted: 10/09/2020] [Indexed: 01/08/2023] Open
Abstract
Phytate and phytases in seeds are the subjects of numerous studies, dating back as far as the early 20th century. Most of these studies concern the anti-nutritional properties of phytate, and the prospect of alleviating the effects of phytate with phytase. As reasonable as this may be, it has led to a fragmentation of knowledge, which hampers the appreciation of the physiological system at hand. In this review, we integrate the existing knowledge on the chemistry and biosynthesis of phytate, the globoid cellular structure, and recent advances on plant phytases. We highlight that these components make up a system that serves to store and-in due time-release the seed's reserves of the mineral nutrients phosphorous, potassium, magnesium, and others, as well as inositol and protein. The central component of the system, the phytate anion, is inherently rich in phosphorous and inositol. The chemical properties of phytate enable it to sequester additional cationic nutrients. Compartmentalization and membrane transport processes regulate the buildup of phytate and its associated nutrients, resulting in globoid storage structures. We suggest, based on the current evidence, that the degradation of the globoid and the mobilization of the nutrients also depend on membrane transport processes, as well as the enzymatic action of phytase.
Collapse
|
10
|
Vashishth A, Ram S, Beniwal V. Cereal phytases and their importance in improvement of micronutrients bioavailability. 3 Biotech 2017; 7:42. [PMID: 28444586 DOI: 10.1007/s13205-017-0698-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 03/15/2017] [Indexed: 10/19/2022] Open
Abstract
Phytic acid is a main reservoir of phosphorous (P) in plants and contributes to about 80% of the total P in cereal seeds. However, it is well known to possess anti-nutritional behavior. Because it has strong affinity to chelate divalent ions e.g. calcium, magnesium, and especially with iron and zinc. Therefore, it is extremely poor as a dietary source of P. To enhance bio-availability of micronutrients, an enzyme namely phytase is known to hydrolyze phytic acid. Unfortunately, phytase is not produced in the stomach of monogastric animals and humans. Thus, the presence of phytic acid in cereal foods has become major concern about the deficiency of essential micronutrients in developing countries. To address this problem, various types of phytase have been isolated, purified and characterized from different varieties of cereal till date. Therefore, the present article discusses about catalytic properties, gene regulation of such cereal phytases and their importance in ensuring food safety.
Collapse
|
11
|
Kilaparty SP, Agarwal R, Singh P, Kannan K, Ali N. Endoplasmic reticulum stress-induced apoptosis accompanies enhanced expression of multiple inositol polyphosphate phosphatase 1 (Minpp1): a possible role for Minpp1 in cellular stress response. Cell Stress Chaperones 2016; 21:593-608. [PMID: 27038811 PMCID: PMC4907990 DOI: 10.1007/s12192-016-0684-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 03/16/2016] [Accepted: 03/17/2016] [Indexed: 01/22/2023] Open
Abstract
Inositol polyphosphates represent a group of differentially phosphorylated inositol metabolites, many of which are implicated to regulate diverse cellular processes such as calcium mobilization, vesicular trafficking, differentiation, apoptosis, etc. The metabolic network of these compounds is complex and tightly regulated by various kinases and phosphatases present predominantly in the cytosol. Multiple inositol polyphosphate phosphatase 1 (Minpp1) is the only known endoplasmic reticulum (ER) luminal enzyme that hydrolyzes various inositol polyphosphates in vitro as well as in vivo conditions. However, access of the Minpp1 to cytosolic substrates has not yet been demonstrated clearly and hence its physiological function. In this study, we examined a potential role for Minpp1 in ER stress-induced apoptosis. We generated a custom antibody and characterized its specificity to study the expression of Minpp1 protein in multiple mammalian cells under experimentally induced cellular stress conditions. Our results demonstrate a significant increase in the expression of Minpp1 in response to a variety of cellular stress conditions. The protein expression was corroborated with the expression of its mRNA and enzymatic activity. Further, in an attempt to link the role of Minpp1 to apoptotic stress, we studied the effect of Minpp1 expression on apoptosis following silencing of the Minpp1 gene by its specific siRNA. Our results suggest an attenuation of apoptotic parameters following knockdown of Minpp1. Thus, in addition to its known role in inositol polyphosphate metabolism, we have identified a novel role for Minpp1 as a stress-responsive protein. In summary, our results provide, for the first time, a probable link between ER stress-induced apoptosis and Minpp1 expression.
Collapse
Affiliation(s)
- Surya P Kilaparty
- Department of Biology, University of Arkansas at Little Rock, 2801 S University Avenue, Little Rock, AR, 72204, USA
| | - Rakhee Agarwal
- Department of Biology, University of Arkansas at Little Rock, 2801 S University Avenue, Little Rock, AR, 72204, USA
- Alexion Pharmaceuticals, Inc., Cheshire, CT, 06410, USA
| | - Pooja Singh
- Department of Biology, University of Arkansas at Little Rock, 2801 S University Avenue, Little Rock, AR, 72204, USA
| | - Krishnaswamy Kannan
- Department of Internal Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Nawab Ali
- Department of Biology, University of Arkansas at Little Rock, 2801 S University Avenue, Little Rock, AR, 72204, USA.
| |
Collapse
|
12
|
Wildberger P, Pfeiffer M, Brecker L, Nidetzky B. Diastereoselektive Synthese von Glykosylphosphaten mit einem Phosphorylase‐Phosphatase‐Kombikatalysator. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201507710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Patricia Wildberger
- Institut für Biotechnologie und Bioprozesstechnik, Technische Universität Graz, Petersgasse 12, 8010 Graz (Österreich)
| | - Martin Pfeiffer
- Institut für Biotechnologie und Bioprozesstechnik, Technische Universität Graz, Petersgasse 12, 8010 Graz (Österreich)
| | - Lothar Brecker
- Institut für Organische Chemie, Universität Wien, Währingerstraße 38, 1090 Wien (Österreich)
| | - Bernd Nidetzky
- Institut für Biotechnologie und Bioprozesstechnik, Technische Universität Graz, Petersgasse 12, 8010 Graz (Österreich)
- acib – Austrian Centre of Industrial Biotechnology (Österreich)
| |
Collapse
|
13
|
Wildberger P, Pfeiffer M, Brecker L, Nidetzky B. Diastereoselective Synthesis of Glycosyl Phosphates by Using a Phosphorylase-Phosphatase Combination Catalyst. Angew Chem Int Ed Engl 2015; 54:15867-71. [PMID: 26565075 PMCID: PMC4737314 DOI: 10.1002/anie.201507710] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Indexed: 11/10/2022]
Abstract
Sugar phosphates play an important role in metabolism and signaling, but also as constituents of macromolecular structures. Selective phosphorylation of sugars is chemically difficult, particularly at the anomeric center. We report phosphatase-catalyzed diastereoselective "anomeric" phosphorylation of various aldose substrates with α-D-glucose 1-phosphate, derived from phosphorylase-catalyzed conversion of sucrose and inorganic phosphate, as the phosphoryl donor. Simultaneous and sequential two-step transformations by the phosphorylase-phosphatase combination catalyst yielded glycosyl phosphates of defined anomeric configuration in yields of up to 70 % based on the phosphate applied to the reaction. An efficient enzyme-assisted purification of the glycosyl phosphate products from reaction mixtures was established.
Collapse
Affiliation(s)
- Patricia Wildberger
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 12, 8010 Graz (Austria)
| | - Martin Pfeiffer
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 12, 8010 Graz (Austria)
| | - Lothar Brecker
- Institute of Organic Chemistry, University of Vienna, Währingerstraße 38, 1090 Vienna (Austria)
| | - Bernd Nidetzky
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 12, 8010 Graz (Austria). .,acib - Austrian Centre of Industrial Biotechnology (Austria).
| |
Collapse
|
14
|
Kilaparty SP, Singh A, Baltosser WH, Ali N. Computational analysis reveals a successive adaptation of multiple inositol polyphosphate phosphatase 1 in higher organisms through evolution. Evol Bioinform Online 2014; 10:239-50. [PMID: 25574123 PMCID: PMC4275298 DOI: 10.4137/ebo.s18948] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 09/29/2014] [Accepted: 10/05/2014] [Indexed: 11/05/2022] Open
Abstract
Multiple inositol polyphosphate phosphatase 1 (Minpp1) in higher organisms dephosphorylates InsP6, the most abundant inositol phosphate. It also dephosphorylates less phosphorylated InsP5 and InsP4 and more phosphorylated InsP7 or InsP8. Minpp1 is classified as a member of the histidine acid phosphatase super family of proteins with functional resemblance to phytases found in lower organisms. This study took a bioinformatics approach to explore the extent of evolutionary diversification in Minpp1 structure and function in order to understand its physiological relevance in higher organisms. The human Minpp1 amino acid (AA) sequence was BLAST searched against available national protein databases. Phylogenetic analysis revealed that Minpp1 was widely distributed from lower to higher organisms. Further, we have identified that there exist four isoforms of Minpp1. Multiple computational tools were used to identify key functional motifs and their conservation among various species. Analyses showed that certain motifs predominant in higher organisms were absent in lower organisms. Variation in AA sequences within motifs was also analyzed. We found that there is diversification of key motifs and thus their functions present in Minpp1 from lower organisms to higher organisms. Another interesting result of this analysis was the presence of a glucose-1-phosphate interaction site in Minpp1; the functional significance of which has yet to be determined experimentally. The overall findings of our study point to an evolutionary adaptability of Minpp1 functions from lower to higher life forms.
Collapse
Affiliation(s)
- Surya P Kilaparty
- Department of Biology, University of Arkansas at Little Rock, Arkansas, USA
| | - Awantika Singh
- UAMS/UALR Joint Bioinformatics Program, University of Arkansas at Little Rock, Arkansas, USA
| | | | - Nawab Ali
- Department of Biology, University of Arkansas at Little Rock, Arkansas, USA
| |
Collapse
|
15
|
Tan DJL, Dvinge H, Christoforou A, Bertone P, Martinez Arias A, Lilley KS. Mapping organelle proteins and protein complexes in Drosophila melanogaster. J Proteome Res 2009; 8:2667-78. [PMID: 19317464 DOI: 10.1021/pr800866n] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Many proteins within eukaryotic cells are organized spatially and functionally into membrane bound organelles and complexes. A protein's location thus provides information about its function. Here, we apply LOPIT, a mass-spectrometry based technique that simultaneously maps proteins to specific subcellular compartments, to Drosophila embryos. We determine the subcellular distribution of hundreds of proteins, and protein complexes. Our results reveal the potential of LOPIT to provide average snapshots of cells.
Collapse
Affiliation(s)
- Denise J L Tan
- Cambridge Systems Biology Centre, Department of Biochemistry, Tennis Court Road, Cambridge CB2 1QR, United Kingdom
| | | | | | | | | | | |
Collapse
|
16
|
Neff CD, Abkevich V, Packer JCL, Chen Y, Potter J, Riley R, Davenport C, DeGrado Warren J, Jammulapati S, Bhathena A, Choi WS, Kroeger PE, Metzger RE, Gutin A, Skolnick MH, Shattuck D, Katz DA. Evidence for HTR1A and LHPP as interacting genetic risk factors in major depression. Mol Psychiatry 2009; 14:621-30. [PMID: 18268499 DOI: 10.1038/mp.2008.8] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The HTR1A -1019C>G genotype was associated with major depression in the Utah population. Linkage analysis on Utah pedigrees with strong family histories of major depression including only cases with the HTR1A -1019G allele revealed a linkage peak on chromosome 10 (maximum HLOD=4.4). Sequencing of all known genes in the linkage region revealed disease-segregating single-nucleotide polymorphisms (SNPs) in LHPP. LHPP SNPs were also associated with major depression in both Utah and Ashkenazi populations. Consistent with the linkage evidence, LHPP associations depended on HTR1A genotype. Lhpp or a product of a collinear brain-specific transcript, therefore, may interact with Htr1a in the pathogenesis of major depression.
Collapse
Affiliation(s)
- C D Neff
- Myriad Genetics, Salt Lake City, UT 84108, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Cho JS. General Enzymatic Properties of Human Histidine Acid Phosphatase-Phytase. JOURNAL OF ANIMAL SCIENCE AND TECHNOLOGY 2009. [DOI: 10.5187/jast.2009.51.2.177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
18
|
Orloff MS, Eng C. Genetic and phenotypic heterogeneity in the PTEN hamartoma tumour syndrome. Oncogene 2008; 27:5387-97. [PMID: 18794875 DOI: 10.1038/onc.2008.237] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Germline PTEN (Phosphatase and TENsin homologue deleted on chromosome TEN) mutations predispose to phenotypically diverse disorders that share several overlapping clinical features: Cowden syndrome, Bannayan-Riley-Ruvalcaba syndrome, Proteus syndrome and Proteus-like syndrome, collectively classified as PTEN hamartoma tumour syndrome (PHTS). The meticulous acquisition and documentation of PHTS phenotypic data at different levels and the profiling of the plethora of genetic changes in PTEN and other genes within the same or related pathways are important in resolving the challenge of discriminating heritable cancers from sporadic PHTS-mimicking clinical features. The characterization of PTEN and PTEN-related pathways from a multidisciplinary perspective underscores the importance of incorporating data from different -omics, which is crucial for the advancement of personalized medicine.
Collapse
Affiliation(s)
- M S Orloff
- Genomic Medicine Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | | |
Collapse
|
19
|
Dionisio G, Holm PB, Brinch-Pedersen H. Wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) multiple inositol polyphosphate phosphatases (MINPPs) are phytases expressed during grain filling and germination. PLANT BIOTECHNOLOGY JOURNAL 2007; 5:325-38. [PMID: 17309687 DOI: 10.1111/j.1467-7652.2007.00244.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
At present, little is known about the phytases of plant seeds in spite of the fact that this group of enzymes is the primary determinant for the utilization of the major phosphate storage compound in seeds, phytic acid. We report the cloning and characterization of complementary DNAs (cDNAs) encoding one of the groups of enzymes with phytase activity, the multiple inositol phosphate phosphatases (MINPPs). Four wheat cDNAs (TaPhyIIa1, TaPhyIIa2, TaPhyIIb and TaPhyIIc) and three barley cDNAs (HvPhyIIa1, HvPhyIIa2 and HvPhyIIb) were isolated. The open reading frames ranged from 1548 to 1554 bp and the level of homology between the barley and wheat proteins ranged from 90.5% to 91.9%. All cDNAs contained an N-terminal signal peptide encoding sequence, and a KDEL-like sequence, KTEL, was present at the C-terminal, indicating that the enzyme was targeted to and retained within the endoplasmic reticulum. Expression of TaPhyIIa2 and HvPhyIIb in Escherichia coli revealed that the MINPPs possessed a significant phytase activity with narrow substrate specificity for phytate. The pH and temperature optima for both enzymes were pH 4.5 and 65 degrees C, respectively, and the K(m) values for phytate were 246 and 334 microm for the wheat and barley recombinant enzymes, respectively. The enzymes were inhibited by several metal ions, in particular copper and zinc. The cDNAs showed significantly different temporal and tissue-specific expression patterns during seed development and germination. With the exception of TaPhyIIb, the cDNAs were present during late seed development and germination. We conclude that MINPPs constitute a significant part of the endogenous phytase potential of the developing and germinating barley and wheat seeds.
Collapse
Affiliation(s)
- Giuseppe Dionisio
- University of Aarhus, Faculty of Agricultural Sciences, Institute of Genetics and Biotechnology, Research Centre Flakkebjerg, DK-4200 Slagelse, Denmark
| | | | | |
Collapse
|
20
|
Affiliation(s)
- Mary F Roberts
- Department of Chemistry, Boston College, Chestnut Hill, MA 02467, USA
| |
Collapse
|
21
|
Mehta BD, Jog SP, Johnson SC, Murthy PPN. Lily pollen alkaline phytase is a histidine phosphatase similar to mammalian multiple inositol polyphosphate phosphatase (MINPP). PHYTOCHEMISTRY 2006; 67:1874-86. [PMID: 16860350 DOI: 10.1016/j.phytochem.2006.06.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Revised: 05/24/2006] [Accepted: 06/06/2006] [Indexed: 05/11/2023]
Abstract
Phytic acid is the most abundant inositol phosphate in cells; it constitutes 1-5% of the dry weight of cereal grains and legumes. Phytases are the primary enzymes responsible for the hydrolysis of phytic acid and thus play important roles in inositol phosphate metabolism. A novel alkaline phytase in lily pollen (LlALP) was recently purified in our laboratory. In this paper, we describe the cloning and characterization of LlALP cDNA from lily pollen. Two isoforms of alkaline phytase cDNAs, LlAlp1 and LlAlp2, which are 1467 and 1533 bp long and encode proteins of 487 and 511 amino acids, respectively, were identified. The deduced amino acid sequences contains the signature heptapeptide of histidine phosphatases, -RHGXRXP-, but shares < 25% identity to fungal histidine acid phytases. Phylogenetic analysis reveals that LlALP is most closely related to multiple inositol polyphosphate phosphatase (MINPP) from humans (25%) and rats (23%). mRNA corresponding to LlAlp1 and LlAlp2 were expressed in leaves, stem, petals and pollen grains. The expression profiles of LlAlp isoforms in anthers indicated that mRNA corresponding to both isoforms were present at all stages of flower development. The expression of LlAlp2 cDNA in Escherichia coli revealed the accumulation of the active enzyme in inclusion bodies and confirmed that the cDNA encodes an alkaline phytase. In summary, plant alkaline phytase is a member of the histidine phosphatase family that includes MINPP and exhibits properties distinct from bacterial and fungal phytases.
Collapse
Affiliation(s)
- Bakul Dhagat Mehta
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931, USA
| | | | | | | |
Collapse
|
22
|
Cho J, Choi K, Darden T, Reynolds PR, Petitte JN, Shears SB. Avian multiple inositol polyphosphate phosphatase is an active phytase that can be engineered to help ameliorate the planet's "phosphate crisis". J Biotechnol 2006; 126:248-59. [PMID: 16759730 PMCID: PMC1892222 DOI: 10.1016/j.jbiotec.2006.04.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Revised: 03/24/2006] [Accepted: 04/07/2006] [Indexed: 11/18/2022]
Abstract
Contemporary phytase research is primarily concerned with ameliorating the problem of inadequate digestion of inositol hexakisphosphate (phytate; InsP6) in monogastric farm animal feed, so as to reduce the pollution that results from the high phosphate content of the manure. In the current study we pursue a new, safe and cost-effective solution. We demonstrate that the rate of hydrolysis of InsP6 by recombinant avian MINPP (0.7 micromol/mg protein/min) defines it as by far the most active phytase found to date in any animal cell (the corresponding activity of recombinant mammalian MINPP is only 0.006 micromol/mg protein/min). Although avian MINPP has less than 20% sequence identity with microbial phytases, we create a homology model of MINPP in which it is predicted that the structure of the phytase active site is well-conserved. This model is validated by site-directed mutagenesis and by use of a substrate analogue, scyllo-InsP6, which we demonstrate is only a weak MINPP substrate. In a model chicken cell line, we overexpressed a mutant form of MINPP that is secretion-competent. This version of the enzyme was actively secreted without affecting either cell viability or the cellular levels of any inositol phosphates. Our studies offer a genetic strategy for greatly improving dietary InsP6 digestion in poultry.
Collapse
Affiliation(s)
- Jaiesoon Cho
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, NIH, DHSS, Research Triangle Park, P.O. Box 12233, NC 27709, USA
| | - Kuicheon Choi
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, NIH, DHSS, Research Triangle Park, P.O. Box 12233, NC 27709, USA
| | - Thomas Darden
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, DHSS, Research Triangle Park, P.O. Box 12233, NC 27709, USA
| | - Paul R. Reynolds
- Department of Environmental and Occupational Health, University of Pittsburgh, 3343 Forbes Avenue, Pittsburgh, PA 15260, USA
| | - James N. Petitte
- College of Agriculture and Life Science, NC State University, Raleigh, NC 27695, USA
| | - Stephen B. Shears
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, NIH, DHSS, Research Triangle Park, P.O. Box 12233, NC 27709, USA
- * Corresponding author. Tel.: +1 919 541 0793; fax: +1 919 541 0559. E-mail address: (S.B. Shears)
| |
Collapse
|
23
|
Delnatte C, Sanlaville D, Mougenot JF, Vermeesch JR, Houdayer C, Blois MCD, Genevieve D, Goulet O, Fryns JP, Jaubert F, Vekemans M, Lyonnet S, Romana S, Eng C, Stoppa-Lyonnet D. Contiguous gene deletion within chromosome arm 10q is associated with juvenile polyposis of infancy, reflecting cooperation between the BMPR1A and PTEN tumor-suppressor genes. Am J Hum Genet 2006; 78:1066-74. [PMID: 16685657 PMCID: PMC1474102 DOI: 10.1086/504301] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2005] [Accepted: 03/14/2006] [Indexed: 12/24/2022] Open
Abstract
We describe four unrelated children who were referred to two tertiary referral medical genetics units between 1991 and 2005 and who are affected with juvenile polyposis of infancy. We show that these children are heterozygous for a germline deletion encompassing two contiguous genes, PTEN and BMPR1A. We hypothesize that juvenile polyposis of infancy is caused by the deletion of these two genes and that the severity of the disease reflects cooperation between these two tumor-suppressor genes.
Collapse
Affiliation(s)
- Capucine Delnatte
- Department of Genetics, Institut Curie, and Departments of Genetics, Pediatrics, and Pathology, Hôpital Necker-Enfants Malades, Assistance Publique–Hôpitaux de Paris, and INSERM Equipe Mixte INSERM E0210, Paris; Center of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium; and Cleveland Clinic Genomic Medicine Institute and Department of Genetics, Case Western Reserve University School of Medicine, Cleveland
| | - Damien Sanlaville
- Department of Genetics, Institut Curie, and Departments of Genetics, Pediatrics, and Pathology, Hôpital Necker-Enfants Malades, Assistance Publique–Hôpitaux de Paris, and INSERM Equipe Mixte INSERM E0210, Paris; Center of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium; and Cleveland Clinic Genomic Medicine Institute and Department of Genetics, Case Western Reserve University School of Medicine, Cleveland
| | - Jean-François Mougenot
- Department of Genetics, Institut Curie, and Departments of Genetics, Pediatrics, and Pathology, Hôpital Necker-Enfants Malades, Assistance Publique–Hôpitaux de Paris, and INSERM Equipe Mixte INSERM E0210, Paris; Center of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium; and Cleveland Clinic Genomic Medicine Institute and Department of Genetics, Case Western Reserve University School of Medicine, Cleveland
| | - Joris-Robert Vermeesch
- Department of Genetics, Institut Curie, and Departments of Genetics, Pediatrics, and Pathology, Hôpital Necker-Enfants Malades, Assistance Publique–Hôpitaux de Paris, and INSERM Equipe Mixte INSERM E0210, Paris; Center of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium; and Cleveland Clinic Genomic Medicine Institute and Department of Genetics, Case Western Reserve University School of Medicine, Cleveland
| | - Claude Houdayer
- Department of Genetics, Institut Curie, and Departments of Genetics, Pediatrics, and Pathology, Hôpital Necker-Enfants Malades, Assistance Publique–Hôpitaux de Paris, and INSERM Equipe Mixte INSERM E0210, Paris; Center of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium; and Cleveland Clinic Genomic Medicine Institute and Department of Genetics, Case Western Reserve University School of Medicine, Cleveland
| | - Marie-Christine de Blois
- Department of Genetics, Institut Curie, and Departments of Genetics, Pediatrics, and Pathology, Hôpital Necker-Enfants Malades, Assistance Publique–Hôpitaux de Paris, and INSERM Equipe Mixte INSERM E0210, Paris; Center of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium; and Cleveland Clinic Genomic Medicine Institute and Department of Genetics, Case Western Reserve University School of Medicine, Cleveland
| | - David Genevieve
- Department of Genetics, Institut Curie, and Departments of Genetics, Pediatrics, and Pathology, Hôpital Necker-Enfants Malades, Assistance Publique–Hôpitaux de Paris, and INSERM Equipe Mixte INSERM E0210, Paris; Center of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium; and Cleveland Clinic Genomic Medicine Institute and Department of Genetics, Case Western Reserve University School of Medicine, Cleveland
| | - Olivier Goulet
- Department of Genetics, Institut Curie, and Departments of Genetics, Pediatrics, and Pathology, Hôpital Necker-Enfants Malades, Assistance Publique–Hôpitaux de Paris, and INSERM Equipe Mixte INSERM E0210, Paris; Center of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium; and Cleveland Clinic Genomic Medicine Institute and Department of Genetics, Case Western Reserve University School of Medicine, Cleveland
| | - Jean-Pierre Fryns
- Department of Genetics, Institut Curie, and Departments of Genetics, Pediatrics, and Pathology, Hôpital Necker-Enfants Malades, Assistance Publique–Hôpitaux de Paris, and INSERM Equipe Mixte INSERM E0210, Paris; Center of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium; and Cleveland Clinic Genomic Medicine Institute and Department of Genetics, Case Western Reserve University School of Medicine, Cleveland
| | - Francis Jaubert
- Department of Genetics, Institut Curie, and Departments of Genetics, Pediatrics, and Pathology, Hôpital Necker-Enfants Malades, Assistance Publique–Hôpitaux de Paris, and INSERM Equipe Mixte INSERM E0210, Paris; Center of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium; and Cleveland Clinic Genomic Medicine Institute and Department of Genetics, Case Western Reserve University School of Medicine, Cleveland
| | - Michel Vekemans
- Department of Genetics, Institut Curie, and Departments of Genetics, Pediatrics, and Pathology, Hôpital Necker-Enfants Malades, Assistance Publique–Hôpitaux de Paris, and INSERM Equipe Mixte INSERM E0210, Paris; Center of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium; and Cleveland Clinic Genomic Medicine Institute and Department of Genetics, Case Western Reserve University School of Medicine, Cleveland
| | - Stanislas Lyonnet
- Department of Genetics, Institut Curie, and Departments of Genetics, Pediatrics, and Pathology, Hôpital Necker-Enfants Malades, Assistance Publique–Hôpitaux de Paris, and INSERM Equipe Mixte INSERM E0210, Paris; Center of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium; and Cleveland Clinic Genomic Medicine Institute and Department of Genetics, Case Western Reserve University School of Medicine, Cleveland
| | - Serge Romana
- Department of Genetics, Institut Curie, and Departments of Genetics, Pediatrics, and Pathology, Hôpital Necker-Enfants Malades, Assistance Publique–Hôpitaux de Paris, and INSERM Equipe Mixte INSERM E0210, Paris; Center of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium; and Cleveland Clinic Genomic Medicine Institute and Department of Genetics, Case Western Reserve University School of Medicine, Cleveland
| | - Charis Eng
- Department of Genetics, Institut Curie, and Departments of Genetics, Pediatrics, and Pathology, Hôpital Necker-Enfants Malades, Assistance Publique–Hôpitaux de Paris, and INSERM Equipe Mixte INSERM E0210, Paris; Center of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium; and Cleveland Clinic Genomic Medicine Institute and Department of Genetics, Case Western Reserve University School of Medicine, Cleveland
| | - Dominique Stoppa-Lyonnet
- Department of Genetics, Institut Curie, and Departments of Genetics, Pediatrics, and Pathology, Hôpital Necker-Enfants Malades, Assistance Publique–Hôpitaux de Paris, and INSERM Equipe Mixte INSERM E0210, Paris; Center of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium; and Cleveland Clinic Genomic Medicine Institute and Department of Genetics, Case Western Reserve University School of Medicine, Cleveland
| |
Collapse
|
24
|
Hidaka K, Kanematsu T, Caffrey JJ, Takeuchi H, Shears SB, Hirata M. The importance to chondrocyte differentiation of changes in expression of the multiple inositol polyphosphate phosphatase. Exp Cell Res 2003; 290:254-64. [PMID: 14567985 DOI: 10.1016/s0014-4827(03)00337-9] [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] [Indexed: 11/19/2022]
Abstract
It is important to both physiological and pathological osteogenesis to understand the significance of changes in gene expression in growth-plate chondrocytes that transit between the proliferative and hypertrophic states. MINPP is one such gene of interest. The Minpp protein dephosphorylates highly phosphorylated inositol signaling molecules InsP(5) and InsP(6). We show here that the ATDC5 chondrocyte progenitor cell line can recapitulate developmentally specific changes in MINPP expression previously only seen in longitudinal bone growth plates-both an initial 2-3-fold increase and a subsequent decrease back to initial levels during transition to hypertrophy. The increase in MINPP expression was accompanied by a 40% decrease in InsP(6) levels in ATDC5 cells. However, InsP(5) levels were not modified. Furthermore, throughout the hypertrophic phase, during which MINPP expression decreased, there were no alterations in InsP(5) and InsP(6) levels. We also created an ATDC5 line that stably overexpressed Minpp at 2-fold higher levels than in wild-type cells. This had no significant effect upon cellular levels of InsP(5) and InsP(6). Thus, substantial changes in MINPP expression can occur without a net effect upon InsP(5) and InsP(6) turnover in vivo. On the other hand, Minpp-overexpressing cells showed impaired chondrogenesis. We noted that the expression of alkaline phosphatase activity was inversely correlated with the expression of MINPP. The ATDC5 cells that overexpress Minpp failed to show an insulin-dependent increase in alkaline phosphatase levels, which presumably affects phosphate balance [J. Biol. Chem. 276 (2001) 33995], and may be the reason cellular differentiation was impaired. In any case, we conclude that Minpp is important to chondrocyte differentiation, but in a manner that is, surprisingly, independent of inositol polyphosphate turnover.
Collapse
Affiliation(s)
- Kiyoshi Hidaka
- Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan.
| | | | | | | | | | | |
Collapse
|
25
|
Lee DC, Cottrill MA, Forsberg CW, Jia Z. Functional insights revealed by the crystal structures of Escherichia coli glucose-1-phosphatase. J Biol Chem 2003; 278:31412-8. [PMID: 12782623 DOI: 10.1074/jbc.m213154200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Escherichia coli periplasmic glucose-1-phosphatase is a member of the histidine acid phosphatase family and acts primarily as a glucose scavenger. Previous substrate profiling studies have demonstrated some of the intriguing properties of the enzyme, including its unique and highly selective inositol phosphatase activity. The enzyme is also potentially involved in pathogenic inositol phosphate signal transduction pathways via type III secretion into the host cell. We have determined the crystal structure of E. coli glucose-1-phosphatase in an effort to unveil the structural mechanism underlying such unique substrate specificity. The structure was determined by the method of multiwavelength anomalous dispersion using a tungstate derivative together with the H18A inactive mutant complex structure with glucose 1-phosphate at 2.4-A resolution. In the active site of glucose-1-phosphatase, there are two unique gating residues, Glu-196 and Leu-24, in addition to the conserved features of histidine acid phosphatases. Together they create steric and electrostatic constraints responsible for the unique selectivity of the enzyme toward phytate and glucose-1-phosphate as well as its unusually high pH optimum for the latter. Based on the structural characterization, we were able to derive simple structural principles that not only precisely explains the substrate specificity of glucose-1-phosphatase and the hydrolysis products of various inositol phosphate substrates but also rationalizes similar general characteristics across the histidine acid phosphatase family.
Collapse
Affiliation(s)
- Daniel C Lee
- Department of Biochemistry, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | | | | | | |
Collapse
|
26
|
Ebner A, Kiefer FN, Ribeiro C, Petit V, Nussbaumer U, Affolter M. Tracheal development in Drosophila melanogaster as a model system for studying the development of a branched organ. Gene 2002; 287:55-66. [PMID: 11992723 DOI: 10.1016/s0378-1119(01)00895-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The development of the tracheal system of Drosophila melanogaster represents a paradigm for studying the molecular mechanisms involved in the formation of a branched tubular network. Tracheogenesis has been characterized at the morphological, cellular and genetic level and a series of successive, but linked events have been described as the basis for the formation of the complex network of tubules which extend over the entire organism. Tracheal cells stop to divide early in the process of tracheogenesis and the formation of the interconnected network requires highly controlled cell migration events and cell shape changes. A number of genes involved in these two processes have been identified but in order to obtain a more complete view of branching morphogenesis, many more genes carrying essential functions have to be isolated and characterized. Here, we provide a progress report on our attempts to identify further genes expressed in the tracheal system. We show that empty spiracles (ems), a head gap gene, is required for the formation of a specific tracheal branch, the visceral branch. We also identified a Sulfotransferase and a Multiple Inositol Polyphosphate phosphatase that are strongly upregulated in tracheal cells and discuss their possible involvement in tracheal development.
Collapse
Affiliation(s)
- Andreas Ebner
- Abteilung Zellbiologie, Biozentrum der Universität Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
| | | | | | | | | | | |
Collapse
|
27
|
Yu WP, Pallen CJ, Tay A, Jirik FR, Brenner S, Tan YH, Venkatesh B. Conserved synteny between the Fugu and human PTEN locus and the evolutionary conservation of vertebrate PTEN function. Oncogene 2001; 20:5554-61. [PMID: 11571655 DOI: 10.1038/sj.onc.1204679] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2001] [Revised: 05/10/2001] [Accepted: 05/10/2001] [Indexed: 11/08/2022]
Abstract
Mutations of PTEN, which encodes a protein-tyrosine and lipid phosphatase, are prevalent in a variety of human cancers. The human genome 'draft' sequence still lacks organization and much of the PTEN and adjacent loci remain undefined. The pufferfish, Fugu rubripes, by virtue of having a compact genome represents an excellent template for rapid vertebrate gene discovery. Sequencing of 56 kb from the Fugu pten (fpten) locus identified four complete genes and one partial gene homologous to human genes. Genes neighboring fpten include a PAPS synthase (fpapss2) differentially expressed between non-metastatic/metastatic human carcinoma cell lines, an inositol phosphatase (fminpp1) and an omega class glutathione-S-transferase (fgsto). We have determined the order of human BAC clones at the hPTEN locus and that the locus contains hPAPSS2 and hMINPP1 genes oriented as are their Fugu orthologs. Although the human genes span 500 kb, the Fugu genes lie within only 22 kb due to the compressed intronic and intergenic regions that typify this genome. Interestingly, and providing striking evidence of regulatory element conservation between widely divergent vertebrate species, the compact 2.1 kb fpten promoter is active in human cells. Also, like hPTEN, fpten has a growth and tumor suppressor activity in human glioblastoma cells, demonstrating conservation of protein function.
Collapse
Affiliation(s)
- W P Yu
- Institute of Molecular and Cell Biology, 30 Medical Drive, Singapore 117609, Republic of Singapore
| | | | | | | | | | | | | |
Collapse
|
28
|
Gimm O, Chi H, Dahia PL, Perren A, Hinze R, Komminoth P, Dralle H, Reynolds PR, Eng C. Somatic mutation and germline variants of MINPP1, a phosphatase gene located in proximity to PTEN on 10q23.3, in follicular thyroid carcinomas. J Clin Endocrinol Metab 2001; 86:1801-5. [PMID: 11297621 DOI: 10.1210/jcem.86.4.7419] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Various genes have been identified to play a role in the pathogenesis of follicular thyroid tumors. Cowden syndrome is the only known familial syndrome with an increased risk of both follicular thyroid adenoma (FA) and carcinoma (FTC). Germline mutations in the tumor suppressor gene PTEN, which encodes a dual-specificity phosphatase, have been found in up to 80% of patients with Cowden syndrome suggesting a role of PTEN in the pathogenesis of follicular thyroid tumors. Although somatic intragenic mutations in PTEN, which maps to 10q23.3, are rarely found in follicular tumors, loss of heterozygosity (LOH) of markers within 10q22-24 occurs in about 25%. Recently, another phosphatase gene, MINPP1, has been localized to 10q23.3. MINPP1 has the ability to remove 3-phosphate from inositol phosphate substrates, a function that overlaps that of PTEN. Because of this overlapping function with PTEN and the physical location of MINPP1 to a region with frequent LOH in follicular thyroid tumors, we considered it to be an excellent candidate gene that could contribute to the pathogenesis of follicular thyroid tumors. We analyzed DNA from tumor and corresponding normal tissue from 23 patients with FA and 15 patients with FTC for LOH and mutations at the MINPP1 locus. LOH was identified in four malignant and three benign tumors. One of these FTCs with LOH was found to harbor a somatic c.122C > T or S41L mutation. We also found two germline sequence variants, c.809A > G (Q270R) and IVS3 + 34T > A. The c.809A > G variant was found in only one patient with FA but not in patients with FTC or normal controls. More interestingly, IVS3 + 34T > A was found in about 15% of FA cases and normal controls but not in patients with FTC. These results suggest a role for MINPP1 in the pathogenesis of at least a subset of malignant follicular thyroid tumors, and MINPP1 might act as a low penetrance predisposition allele for FTC.
Collapse
Affiliation(s)
- O Gimm
- Clinical Cancer Genetics Program, Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Abstract
This review assesses the authenticity of inositol hexakisphosphate (InsP(6)) being a wide-ranging regulator of many important cellular functions. Against a background in which the possible importance of localized InsP(6) metabolism is discussed, there is the facile explanation that InsP(6) is merely an "inactive" precursor for the diphosphorylated inositol phosphates. Indeed, many of the proposed cellular functions of InsP(6) cannot sustain a challenge from the implementation of a rigorous set of criteria, which are designed to avoid experimental artefacts.
Collapse
Affiliation(s)
- S B Shears
- Inositol Signaling Section, Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, 27709, Research Triangle Park, NC, USA.
| |
Collapse
|
30
|
Chi H, Yang X, Kingsley PD, O'Keefe RJ, Puzas JE, Rosier RN, Shears SB, Reynolds PR. Targeted deletion of Minpp1 provides new insight into the activity of multiple inositol polyphosphate phosphatase in vivo. Mol Cell Biol 2000; 20:6496-507. [PMID: 10938126 PMCID: PMC86124 DOI: 10.1128/mcb.20.17.6496-6507.2000] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multiple inositol polyphosphate phosphatase (Minpp1) metabolizes inositol 1,3,4,5,6-pentakisphosphate (InsP(5)) and inositol hexakisphosphate (InsP(6)) with high affinity in vitro. However, Minpp1 is compartmentalized in the endoplasmic reticulum (ER) lumen, where access of enzyme to these predominantly cytosolic substrates in vivo has not previously been demonstrated. To gain insight into the physiological activity of Minpp1, Minpp1-deficient mice were generated by homologous recombination. Tissue extracts from Minpp1-deficient mice lacked detectable Minpp1 mRNA expression and Minpp1 enzyme activity. Unexpectedly, Minpp1-deficient mice were viable, fertile, and without obvious defects. Although Minpp1 expression is upregulated during chondrocyte hypertrophy, normal chondrocyte differentiation and bone development were observed in Minpp1-deficient mice. Biochemical analyses demonstrate that InsP(5) and InsP(6) are in vivo substrates for ER-based Minpp1, as levels of these polyphosphates in Minpp1-deficient embryonic fibroblasts were 30 to 45% higher than in wild-type cells. This increase was reversed by reintroducing exogenous Minpp1 into the ER. Thus, ER-based Minpp1 plays a significant role in the maintenance of steady-state levels of InsP(5) and InsP(6). These polyphosphates could be reduced below their natural levels by aberrant expression in the cytosol of a truncated Minpp1 lacking its ER-targeting N terminus. This was accompanied by slowed cellular proliferation, indicating that maintenance of cellular InsP(5) and InsP(6) is essential to normal cell growth. Yet, depletion of cellular inositol polyphosphates during erythropoiesis emerges as an additional physiological activity of Minpp1; loss of this enzyme activity in erythrocytes from Minpp1-deficient mice was accompanied by upregulation of a novel, substitutive inositol polyphosphate phosphatase.
Collapse
Affiliation(s)
- H Chi
- Department of Pathology and Laboratory Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Yeh JJ, Marsh DJ, Zedenius J, Dwight T, Delbridge L, Robinson BG, Eng C. Fine-structure deletion mapping of 10q22-24 identifies regions of loss of heterozygosity and suggests that sporadic follicular thyroid adenomas and follicular thyroid carcinomas develop along distinct neoplastic pathways. Genes Chromosomes Cancer 1999; 26:322-8. [PMID: 10534767 DOI: 10.1002/(sici)1098-2264(199912)26:4<322::aid-gcc6>3.0.co;2-#] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Previous studies have demonstrated frequent loss of heterozygosity (LOH) of markers on chromosome arm 10q in both follicular thyroid carcinomas (FTCs) and follicular thyroid adenomas (FAs). A novel tumor suppressor gene, PTEN, has been mapped to 10q23.3 and is the susceptibility gene for Cowden syndrome, an autosomal dominant disorder characterized by multiple hamartomas and a risk of benign and malignant tumors of the breast and thyroid. Studies examining the relationship of somatic PTEN status and follicular thyroid neoplasms have only demonstrated a variable subset of tumors that have somatic monoallelic deletions of PTEN, suggesting that other tumor suppressor genes may be present in this region. We therefore sought to conduct a detailed examination of LOH of 20 polymorphic markers in a 19-cM region spanning 10q22-24, including PTEN, in 44 FAs and 17 FTCs. Using this fine-structure somatic mapping approach, we defined at least two novel regions of LOH in follicular adenomas and follicular carcinomas, suggesting the presence of at least two distinct tumor suppressor genes that may play a role in thyroid neoplasia. Furthermore, the difference in patterns of LOH in adenomas versus carcinomas lends additional support to the hypothesis that adenomas and carcinomas can develop along two separate, nonserial pathways. Genes Chromosomes Cancer 26:322-328, 1999.
Collapse
Affiliation(s)
- J J Yeh
- Clinical Cancer Genetics and Human Cancer Genetics Programs, Ohio State University Comprehensive Cancer Center, Columbus, Ohio 43210, USA
| | | | | | | | | | | | | |
Collapse
|