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Meng J, Chen X, Han Z. PFKFB4 promotes lung adenocarcinoma progression via phosphorylating and activating transcriptional coactivator SRC-2. BMC Pulm Med 2021; 21:60. [PMID: 33593309 PMCID: PMC7887818 DOI: 10.1186/s12890-021-01420-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 01/27/2021] [Indexed: 11/22/2022] Open
Abstract
Background To investigate the role and its potential mechanism of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4 (PFKFB4) in lung adenocarcinoma. Methods Co-immunoprecipitation was performed to analyze the interaction between PFKFB4 and SRC-2. Western blot was used to investigate the phosphorylation of steroid receptor coactivator-2 (SRC-2) on the condition that PFKFB4 was knockdown. Transcriptome sequencing was performed to find the downstream target of SRC-2. Cell Counting Kit-8 (CCK-8) assay, transwell assay and transwell-matrigel assay were used to examine the proliferation, migration and invasion abilities in A549 and NCI-H1975 cells with different treatment. Results In our study we found that PFKFB4 was overexpressed in lung adenocarcinoma associated with SRC family protein and had an interaction with SRC-2. PFKFB4 could phosphorylate SRC-2 at Ser487, which altered SRC-2 transcriptional activity. Functionally, PFKFB4 promoted lung adenocarcinoma cells proliferation, migration and invasion by phosphorylating SRC-2. Furthermore, we identified that CARM1 was transcriptionally regulated by SRC-2 and involved in PFKFB4-SRC-2 axis on lung adenocarcinoma progression. Conclusions Our research reveal that PFKFB4 promotes lung adenocarcinoma cells proliferation, migration and invasion via enhancing phosphorylated SRC-2-mediated CARM1 expression.
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Affiliation(s)
- Jiguang Meng
- Department of Respiratory Medicine, Sixth Medical Center of Chinese People's Liberation Army General Hospital, Beijing, 100048, China
| | - Xuxin Chen
- Department of Respiratory Medicine, Sixth Medical Center of Chinese People's Liberation Army General Hospital, Beijing, 100048, China
| | - Zhihai Han
- Department of Respiratory Medicine, Sixth Medical Center of Chinese People's Liberation Army General Hospital, Beijing, 100048, China.
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2
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Sellem CH, Humbert A, Sainsard-Chanet A. Mutations in the phosphatase domain of the 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase result in the transcriptional activation of the alternative oxidase and gluconeogenic pathways in Podospora anserina. Fungal Genet Biol 2019; 130:1-10. [PMID: 30980907 DOI: 10.1016/j.fgb.2019.04.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 03/01/2019] [Accepted: 04/03/2019] [Indexed: 11/29/2022]
Abstract
By screening suppressors of a respiratory mutant lacking a functional cytochrome pathway in the filamentous fungus Podospora anserina, we isolated a mutation located in the phosphatase domain of the bi-functional enzyme 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase (PFK-2/FBPase-2). We show that the inactivation of the phosphatase but not of the kinase domain is responsible for the suppressor effect that results from the activation of the RSEs transcription factors that control expression of AOX, an alternative oxidase able to bypass the mitochondria cytochrome pathway of respiration. Remarkably, activation of the RSEs also stimulates the expression of the gluconeogenic enzymes, fructose-1,6 bi-phosphatase (FBPase-1) and phosphoenolpyruvate carboxykinase (PCK-1). We thus reveal in P. anserina an apparently paradoxical situation where the inactivation of the phosphatase domain of PFK-2/FBPase-2, supposed to stimulate glycolysis, is correlated with the transcriptional induction of the gluconeogenic enzymes. Phylogenic analysis revealed the presence of multiple presumed PFK-2/FBPase-2 isoforms in all the species of tested Ascomycetes.
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Affiliation(s)
- Carole H Sellem
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France.
| | - Adeline Humbert
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Annie Sainsard-Chanet
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
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3
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Bartrons R, Simon-Molas H, Rodríguez-García A, Castaño E, Navarro-Sabaté À, Manzano A, Martinez-Outschoorn UE. Fructose 2,6-Bisphosphate in Cancer Cell Metabolism. Front Oncol 2018; 8:331. [PMID: 30234009 PMCID: PMC6131595 DOI: 10.3389/fonc.2018.00331] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 08/01/2018] [Indexed: 01/28/2023] Open
Abstract
For a long time, pioneers in the field of cancer cell metabolism, such as Otto Warburg, have focused on the idea that tumor cells maintain high glycolytic rates even with adequate oxygen supply, in what is known as aerobic glycolysis or the Warburg effect. Recent studies have reported a more complex situation, where the tumor ecosystem plays a more critical role in cancer progression. Cancer cells display extraordinary plasticity in adapting to changes in their tumor microenvironment, developing strategies to survive and proliferate. The proliferation of cancer cells needs a high rate of energy and metabolic substrates for biosynthesis of biomolecules. These requirements are met by the metabolic reprogramming of cancer cells and others present in the tumor microenvironment, which is essential for tumor survival and spread. Metabolic reprogramming involves a complex interplay between oncogenes, tumor suppressors, growth factors and local factors in the tumor microenvironment. These factors can induce overexpression and increased activity of glycolytic isoenzymes and proteins in stromal and cancer cells which are different from those expressed in normal cells. The fructose-6-phosphate/fructose-1,6-bisphosphate cycle, catalyzed by 6-phosphofructo-1-kinase/fructose 1,6-bisphosphatase (PFK1/FBPase1) isoenzymes, plays a key role in controlling glycolytic rates. PFK1/FBpase1 activities are allosterically regulated by fructose-2,6-bisphosphate, the product of the enzymatic activity of the dual kinase/phosphatase family of enzymes: 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase (PFKFB1-4) and TP53-induced glycolysis and apoptosis regulator (TIGAR), which show increased expression in a significant number of tumor types. In this review, the function of these isoenzymes in the regulation of metabolism, as well as the regulatory factors modulating their expression and activity in the tumor ecosystem are discussed. Targeting these isoenzymes, either directly or by inhibiting their activating factors, could be a promising approach for treating cancers.
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Affiliation(s)
- Ramon Bartrons
- Unitat de Bioquímica, Departament de Ciències Fisiològiques, Universitat de Barcelona, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Catalunya, Spain
| | - Helga Simon-Molas
- Unitat de Bioquímica, Departament de Ciències Fisiològiques, Universitat de Barcelona, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Catalunya, Spain
| | - Ana Rodríguez-García
- Unitat de Bioquímica, Departament de Ciències Fisiològiques, Universitat de Barcelona, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Catalunya, Spain
| | - Esther Castaño
- Centres Científics i Tecnològics, Universitat de Barcelona, Catalunya, Spain
| | - Àurea Navarro-Sabaté
- Unitat de Bioquímica, Departament de Ciències Fisiològiques, Universitat de Barcelona, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Catalunya, Spain
| | - Anna Manzano
- Unitat de Bioquímica, Departament de Ciències Fisiològiques, Universitat de Barcelona, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Catalunya, Spain
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Bartrons R, Rodríguez-García A, Simon-Molas H, Castaño E, Manzano A, Navarro-Sabaté À. The potential utility of PFKFB3 as a therapeutic target. Expert Opin Ther Targets 2018; 22:659-674. [PMID: 29985086 DOI: 10.1080/14728222.2018.1498082] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
INTRODUCTION It has been known for over half a century that tumors exhibit an increased demand for nutrients to fuel their rapid proliferation. Interest in targeting cancer metabolism to treat the disease has been renewed in recent years with the discovery that many cancer-related pathways have a profound effect on metabolism. Considering the recent increase in our understanding of cancer metabolism and the enzymes and pathways involved, the question arises as to whether metabolism is cancer's Achilles heel. Areas covered: This review summarizes the role of 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) in glycolysis, cell proliferation, and tumor growth, discussing PFKFB3 gene and isoenzyme regulation and the changes that occur in cancer and inflammatory diseases. Pharmacological options currently available for selective PFKFB3 inhibition are also reviewed. Expert opinion: PFKFB3 plays an important role in sustaining the development and progression of cancer and might represent an attractive target for therapeutic strategies. Nevertheless, clinical trials are needed to follow up on the promising results from preclinical studies with PFKFB3 inhibitors. Combination therapies with PFKFB3 inhibitors, chemotherapeutic drugs, or radiotherapy might improve the efficacy of cancer treatments targeting PFKFB3.
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Affiliation(s)
- Ramon Bartrons
- a Unitat de Bioquímica, Departament de Ciències Fisiològiques , Universitat de Barcelona, IDIBELL , Catalunya , Spain
| | - Ana Rodríguez-García
- a Unitat de Bioquímica, Departament de Ciències Fisiològiques , Universitat de Barcelona, IDIBELL , Catalunya , Spain
| | - Helga Simon-Molas
- a Unitat de Bioquímica, Departament de Ciències Fisiològiques , Universitat de Barcelona, IDIBELL , Catalunya , Spain
| | - Esther Castaño
- a Unitat de Bioquímica, Departament de Ciències Fisiològiques , Universitat de Barcelona, IDIBELL , Catalunya , Spain
| | - Anna Manzano
- a Unitat de Bioquímica, Departament de Ciències Fisiològiques , Universitat de Barcelona, IDIBELL , Catalunya , Spain
| | - Àurea Navarro-Sabaté
- a Unitat de Bioquímica, Departament de Ciències Fisiològiques , Universitat de Barcelona, IDIBELL , Catalunya , Spain
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Dasgupta S, Rajapakshe K, Zhu B, Nikolai BC, Yi P, Putluri N, Choi JM, Jung SY, Coarfa C, Westbrook TF, Zhang XHF, Foulds CE, Tsai SY, Tsai MJ, O'Malley BW. Metabolic enzyme PFKFB4 activates transcriptional coactivator SRC-3 to drive breast cancer. Nature 2018; 556:249-254. [PMID: 29615789 PMCID: PMC5895503 DOI: 10.1038/s41586-018-0018-1] [Citation(s) in RCA: 146] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 02/28/2018] [Indexed: 01/27/2023]
Abstract
Alterations in both cell metabolism and transcriptional programs are hallmarks of cancer that sustain rapid proliferation and metastasis 1 . However, the mechanisms that control the interaction between metabolic reprogramming and transcriptional regulation remain unclear. Here we show that the metabolic enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4 (PFKFB4) regulates transcriptional reprogramming by activating the oncogenic steroid receptor coactivator-3 (SRC-3). We used a kinome-wide RNA interference-based screening method to identify potential kinases that modulate the intrinsic SRC-3 transcriptional response. PFKFB4, a regulatory enzyme that synthesizes a potent stimulator of glycolysis 2 , is found to be a robust stimulator of SRC-3 that coregulates oestrogen receptor. PFKFB4 phosphorylates SRC-3 at serine 857 and enhances its transcriptional activity, whereas either suppression of PFKFB4 or ectopic expression of a phosphorylation-deficient Ser857Ala mutant SRC-3 abolishes the SRC-3-mediated transcriptional output. Functionally, PFKFB4-driven SRC-3 activation drives glucose flux towards the pentose phosphate pathway and enables purine synthesis by transcriptionally upregulating the expression of the enzyme transketolase. In addition, the two enzymes adenosine monophosphate deaminase-1 (AMPD1) and xanthine dehydrogenase (XDH), which are involved in purine metabolism, were identified as SRC-3 targets that may or may not be directly involved in purine synthesis. Mechanistically, phosphorylation of SRC-3 at Ser857 increases its interaction with the transcription factor ATF4 by stabilizing the recruitment of SRC-3 and ATF4 to target gene promoters. Ablation of SRC-3 or PFKFB4 suppresses breast tumour growth in mice and prevents metastasis to the lung from an orthotopic setting, as does Ser857Ala-mutant SRC-3. PFKFB4 and phosphorylated SRC-3 levels are increased and correlate in oestrogen receptor-positive tumours, whereas, in patients with the basal subtype, PFKFB4 and SRC-3 drive a common protein signature that correlates with the poor survival of patients with breast cancer. These findings suggest that the Warburg pathway enzyme PFKFB4 acts as a molecular fulcrum that couples sugar metabolism to transcriptional activation by stimulating SRC-3 to promote aggressive metastatic tumours.
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Affiliation(s)
- Subhamoy Dasgupta
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.
- Department of Cell Stress Biology, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA.
| | - Kimal Rajapakshe
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Bokai Zhu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Bryan C Nikolai
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Ping Yi
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Nagireddy Putluri
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Jong Min Choi
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Sung Y Jung
- Verna & Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Cristian Coarfa
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Thomas F Westbrook
- Verna & Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Xiang H-F Zhang
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Charles E Foulds
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
- Center for Precision Environmental Health, Baylor College of Medicine, Houston, TX, USA
| | - Sophia Y Tsai
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Ming-Jer Tsai
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Bert W O'Malley
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.
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Hagopian K, Kim K, López-Dominguez JA, Tomilov AA, Cortopassi GA, Ramsey JJ. Mice with low levels of Shc proteins display reduced glycolytic and increased gluconeogenic activities in liver. Biochem Biophys Rep 2016; 7:273-286. [PMID: 28133633 PMCID: PMC5267479 DOI: 10.1016/j.bbrep.2016.06.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Shc proteins play a role in energy metabolism through interaction with the insulin receptor. The aim of this study was to determine whether Shc proteins influence liver glycolysis and gluconeogenesis under both fed and fasted states. Decreased glycolytic and increased gluconeogenic and transamination enzyme activities were observed in ShcKO versus WT mice. Levels of key regulatory metabolites, such as fructose-2,6-bisphosphate, matched the activity of metabolic pathways. Protein levels of glycolytic and gluconeogenic enzymes were not different. pAMPK protein levels increased with fasting and were higher in ShcKO versus WT mice. Therefore, Shc proteins play a role in shifting the metabolism from glucose oxidation to gluconeogenesis and lipid catabolism and should be considered as regulators of fuel selection. Fuel selection and utilization could play a critical role in healthy aging. Characterization of metabolic events in ShcKO mice would help to elucidate how metabolism is influenced by these proteins. Decreased glycolysis and increased gluconeogenesis in ShcKO mice. Changes in metabolite levels reflect changes in enzyme activities. Protein levels of key enzymes remained unchanged. Shc proteins play a role in metabolic shift and act as regulators of fuel selection.
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Affiliation(s)
- Kevork Hagopian
- VM Molecular Biosciences, School of Veterinary Medicine, University of California, Davis 1089 Veterinary Medicine Dr, VM3B, Davis, CA 95616, USA
- Corresponding author.
| | - Kyoungmi Kim
- Department of Public Health Sciences, University of California Davis, Davis, CA 95616, USA
| | - José Alberto López-Dominguez
- VM Molecular Biosciences, School of Veterinary Medicine, University of California, Davis 1089 Veterinary Medicine Dr, VM3B, Davis, CA 95616, USA
| | - Alexey A. Tomilov
- VM Molecular Biosciences, School of Veterinary Medicine, University of California, Davis 1089 Veterinary Medicine Dr, VM3B, Davis, CA 95616, USA
| | - Gino A. Cortopassi
- VM Molecular Biosciences, School of Veterinary Medicine, University of California, Davis 1089 Veterinary Medicine Dr, VM3B, Davis, CA 95616, USA
| | - Jon J. Ramsey
- VM Molecular Biosciences, School of Veterinary Medicine, University of California, Davis 1089 Veterinary Medicine Dr, VM3B, Davis, CA 95616, USA
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Regulation of Glucose Homeostasis by Glucocorticoids. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015. [PMID: 26215992 DOI: 10.1007/978-1-4939-2895-8_5] [Citation(s) in RCA: 355] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glucocorticoids are steroid hormones that regulate multiple aspects of glucose homeostasis. Glucocorticoids promote gluconeogenesis in liver, whereas in skeletal muscle and white adipose tissue they decrease glucose uptake and utilization by antagonizing insulin response. Therefore, excess glucocorticoid exposure causes hyperglycemia and insulin resistance. Glucocorticoids also regulate glycogen metabolism. In liver, glucocorticoids increase glycogen storage, whereas in skeletal muscle they play a permissive role for catecholamine-induced glycogenolysis and/or inhibit insulin-stimulated glycogen synthesis. Moreover, glucocorticoids modulate the function of pancreatic α and β cells to regulate the secretion of glucagon and insulin, two hormones that play a pivotal role in the regulation of blood glucose levels. Overall, the major glucocorticoid effect on glucose homeostasis is to preserve plasma glucose for brain during stress, as transiently raising blood glucose is important to promote maximal brain function. In this chapter we will discuss the current understanding of the mechanisms underlying different aspects of glucocorticoid-regulated mammalian glucose homeostasis.
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Hagopian K, Tomilov AA, Kim K, Cortopassi GA, Ramsey JJ. Key glycolytic enzyme activities of skeletal muscle are decreased under fed and fasted states in mice with knocked down levels of Shc proteins. PLoS One 2015; 10:e0124204. [PMID: 25880638 PMCID: PMC4400099 DOI: 10.1371/journal.pone.0124204] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 03/10/2015] [Indexed: 11/18/2022] Open
Abstract
Shc proteins interact with the insulin receptor, indicating a role in regulating glycolysis. To investigate this idea, the activities of key glycolytic regulatory enzymes and metabolites levels were measured in skeletal muscle from mice with low levels of Shc proteins (ShcKO) and wild-type (WT) controls. The activities of hexokinase, phosphofructokinase-1 and pyruvate kinase were decreased in ShcKO versus WT mice under both fed and fasted conditions. Increased alanine transaminase and branched-chain amino acid transaminase activities were also observed in ShcKO mice under both fed and fasting conditions. Protein expression of glycolytic enzymes was unchanged in the ShcKO and WT mice, indicating that decreased activities were not due to changes in their transcription. Changes in metabolite levels were consistent with the observed changes in enzyme activities. In particular, the levels of fructose-2,6-bisphosphate, a potent activator of phosphofructokinase-1, were consistently decreased in the ShcKO mice. Furthermore, the levels of lactate (inhibitor of hexokinase and phosphofructokinase-1) and citrate (inhibitor of phosphofructokinase-1 and pyruvate kinase) were increased in fed and fasted ShcKO versus WT mice. Pyruvate dehydrogenase activity was lower in ShcKO versus WT mice under fed conditions, and showed inhibition under fasting conditions in both ShcKO and WT mice, with ShcKO mice showing less inhibition than the WT mice. Pyruvate dehydrogenase kinase 4 levels were unchanged under fed conditions but were lower in the ShcKO mice under fasting conditions. These studies indicate that decreased levels of Shc proteins in skeletal muscle lead to a decreased glycolytic capacity in both fed and fasted states.
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Affiliation(s)
- Kevork Hagopian
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, United States of America
- * E-mail:
| | - Alexey A. Tomilov
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, United States of America
| | - Kyoungmi Kim
- Department of Public Health Sciences, University of California Davis, Davis, CA 95616, United States of America
| | - Gino A. Cortopassi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, United States of America
| | - Jon J. Ramsey
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, United States of America
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Cosin-Roger J, Vernia S, Alvarez MS, Cucarella C, Boscá L, Martin-Sanz P, Fernández-Alvarez AJ, Casado M. Identification of a novel Pfkfb1 mRNA variant in rat fetal liver. Biochem Biophys Res Commun 2013; 431:36-40. [PMID: 23291237 DOI: 10.1016/j.bbrc.2012.12.109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 12/13/2012] [Indexed: 02/07/2023]
Abstract
The bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2) catalyzes the synthesis and degradation of fructose-2,6-bisphosphate, a key metabolite in the glucose homeostasis. Four genes, Pfkfb1-4, have been characterized in mammals that code for several isoforms generated by alternative splicing through the control of several promoters and 5' non-coding exons. Here, we characterize in fetal rat liver new mRNA variants which are transcribed from a new Pfkfb1 gene promoter. The long variant codes to a new isoform (FL-PFK-2) that would be of relevant function to modulate the transition of fetal to adult liver metabolism.
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Affiliation(s)
- Jesús Cosin-Roger
- Instituto de Biomedicina de Valencia, IBV-CSIC, Jaime Roig 11, 46010 Valencia, Spain
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Wang Y, Yi H, Wang M, Yu O, Jez JM. Structural and kinetic analysis of the unnatural fusion protein 4-coumaroyl-CoA ligase::stilbene synthase. J Am Chem Soc 2011; 133:20684-7. [PMID: 22129213 DOI: 10.1021/ja2085993] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
To increase the biochemical efficiency of biosynthetic systems, metabolic engineers have explored different approaches for organizing enzymes, including the generation of unnatural fusion proteins. Previous work aimed at improving the biosynthesis of resveratrol, a stilbene associated a range of health-promoting activities, in yeast used an unnatural engineered fusion protein of Arabidopsis thaliana (thale cress) 4-coumaroyl-CoA ligase (At4CL1) and Vitis vinifera (grape) stilbene synthase (VvSTS) to increase resveratrol levels 15-fold relative to yeast expressing the individual enzymes. Here we present the crystallographic and biochemical analysis of the 4CL::STS fusion protein. Determination of the X-ray crystal structure of 4CL::STS provides the first molecular view of an artificial didomain adenylation/ketosynthase fusion protein. Comparison of the steady-state kinetic properties of At4CL1, VvSTS, and 4CL::STS demonstrates that the fusion protein improves catalytic efficiency of either reaction less than 3-fold. Structural and kinetic analysis suggests that colocalization of the two enzyme active sites within 70 Å of each other provides the basis for enhanced in vivo synthesis of resveratrol.
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Affiliation(s)
- Yechun Wang
- Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, Missouri 63132, USA
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Androgen stimulates glycolysis for de novo lipid synthesis by increasing the activities of hexokinase 2 and 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 2 in prostate cancer cells. Biochem J 2011; 433:225-33. [PMID: 20958264 DOI: 10.1042/bj20101104] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Up-regulation of lipogenesis by androgen is one of the most characteristic metabolic features of LNCaP prostate cancer cells. The present study revealed that androgen increases glucose utilization for de novo lipogenesis in LNCaP cells through the activation of HK2 (hexokinase 2) and activation of the cardiac isoform of PFKFB2 (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase). Activation of PKA (cAMP-dependent protein kinase) by androgen increased phosphorylation of CREB [CRE (cAMP-response element)-binding protein], which in turn bound to CRE on the promoter of the HK2 gene resulting in transcriptional activation of the HK2 gene. Up-regulation of PFKFB2 expression was mediated by the direct binding of ligand-activated androgen receptor to the PFKFB2 promoter. The activated PI3K (phosphoinositide 3-kinase)/Akt signalling pathway in LNCaP cells contributes to the phosphorylation of PFKFB2 at Ser466 and Ser483, resulting in the constitutive activation of PFK-2 (6-phosphofructo-2-kinase) activity. Glucose uptake and lipogenesis were severely blocked by knocking-down of PFKFB2 using siRNA (small interfering RNA) or by inhibition of PFK-2 activity with LY294002 treatment. Taken together, our results suggest that the induction of de novo lipid synthesis by androgen requires the transcriptional up-regulation of HK2 and PFKFB2, and phosphorylation of PFKFB2 generated by the PI3K/Akt signalling pathway to supply the source for lipogenesis from glucose in prostate cancer cells.
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Zscharnack K, Kessler R, Bleichert F, Warnke JP, Eschrich K. The PFKFB3 splice variant UBI2K4 is downregulated in high-grade astrocytomas and impedes the growth of U87 glioblastoma cells. Neuropathol Appl Neurobiol 2009; 35:566-78. [PMID: 19490427 DOI: 10.1111/j.1365-2990.2009.01027.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
AIMS Fructose-2,6-bisphosphate, a key regulator of glycolysis, is synthesized and degraded by four different isozymes of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB1-4). The PFKFB3 isozyme is upregulated in several human tumours. Six alternatively spliced variants of PFKFB3 mRNA are known in humans (UBI2K1-6). Here, we studied the role of the PFKFB3 splice variants in human astrocytic gliomas. METHODS We analysed the PFKFB3 splice variants in 48 astrocytic gliomas by RT-PCR and real-time PCR. The effect of transient and stable overexpression of the PFKFB3 isoforms was studied in U87 glioblastoma cells by MTT, cell counting, clone formation assay and metabolic measurements. RESULTS UBI2K5 and UBI2K6 are the predominant splice variants in rapidly proliferating high-grade astrocytomas while the expression of UBI2K3 and UBI2K4 is mainly restricted to low-grade astrocytomas and nonneoplastic brain tissue. Overexpression of UBI2K5 or UBI2K6 in the U87 glioblastoma cell line enhances the glycolytic flux but does not affect cell growth. In contrast, overexpression of UBI2K4 reduces cell viability and anchorage-independent growth of U87 cells. The UBI2K4 mRNA level is downregulated in astrocytic gliomas with increasing malignancy grade. Moreover, the UBI2K4 mRNA level correlates with growth rate of several human cancer cell lines derived from different tissue types. CONCLUSIONS Our results demonstrate that the splice variant UBI2K4 impedes the tumour cell growth and might serve as a tumour suppressor in astrocytic tumours.
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Affiliation(s)
- K Zscharnack
- Institute of Biochemistry, University of Leipzig, Germany
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13
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Mykhalchenko VG, Tsuchihara K, Minchenko DO, Esumi H, Prystupiuk OM, Minchenko OH. 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase mRNA expression in streptozotocin-diabetic rats. ACTA ACUST UNITED AC 2008. [DOI: 10.7124/bc.0007a9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- V. G. Mykhalchenko
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine
| | | | - D. O. Minchenko
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine
| | - H. Esumi
- National Cancer Center Hospital East
| | - O. M. Prystupiuk
- Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine
| | - O. H. Minchenko
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine
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14
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Minchenko OH, Ogura T, Opentanova IL, Minchenko DO, Esumi H. Splice isoform of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-4: expression and hypoxic regulation. Mol Cell Biochem 2006; 280:227-34. [PMID: 16311927 DOI: 10.1007/s11010-005-8009-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2005] [Accepted: 05/26/2005] [Indexed: 12/24/2022]
Abstract
The 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB) is responsible for maintaining the cellular levels of fructose-2,6-bisphosphate which is a key regulator of glycolysis. Here we have studied the expression of PFKFB-4 isozyme in the DB-1 melanoma cells. An additional isoform of PFKFB-4 mRNA with 148 bases insert in the amino-terminal region at high constitutive levels was identified in these cells. The expression of this splice isoform as well as main isoform of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase was responsible to hypoxia and dimethyloxalylglycine, an inhibitor of HIF-1 alpha hydroxylase enzymes, suggesting that the hypoxia responsiveness of PFKFB-4 gene in these cells is regulated by HIF-1alpha protein. Hypoxic induction of PFKFB4 mRNA in the DB-1 melanoma cells correlates with the expression of PFKFB-3 and VEGF mRNA which are known as HIF-1 dependent genes. Thus, our results clearly demonstrated the existence of splice isoform of PFKFB-4 mRNA in the DB-1 melanoma cells and its overexpression under hypoxic conditions.
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Affiliation(s)
- Oleksandr H Minchenko
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovycha Street, Kyiv, 01601, Ukraine.
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15
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Minchenko OH, Ochiai A, Opentanova IL, Ogura T, Minchenko DO, Caro J, Komisarenko SV, Esumi H. Overexpression of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-4 in the human breast and colon malignant tumors. Biochimie 2006; 87:1005-10. [PMID: 15925437 DOI: 10.1016/j.biochi.2005.04.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2005] [Revised: 03/24/2005] [Accepted: 04/04/2005] [Indexed: 11/28/2022]
Abstract
6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB) is a bifunctional enzyme, which is responsible for maintaining the cellular level of fructose-2,6-bisphosphate, a powerful allosteric activator of glycolysis. We describe herein the overexpression of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-4 (PFKFB-4) isozyme in the human breast and colon malignant tumors as compared to corresponding non-malignant tissue counterparts. We have shown also that breast malignant cell line MCF7 constitutively express PFKFB-4 mRNA and that the expression of this gene is highly induced by hypoxia. Overexpression of PFKFB-4 transcript levels in breast and colon malignant tumors correlates with enhanced expression of PFKFB-3, hypoxia-inducible factor (HIF)-1alpha and known HIF-1 dependent genes glucose transporter 1 (Glut1) and vascular endothelial growth factor (VEGF). Thus, our data clearly demonstrates overexpression of PFKFB-4 mRNA and protein in the breast and colon malignant tumors.
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Affiliation(s)
- O H Minchenko
- Department of Molecular Biology, Palladin Institute of Biochemistry National Academy of Science of Ukraine, Kyiv 01601, Ukraine.
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16
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Minchenko O, Opentanova I, Minchenko D, Ogura T, Esumi H. Hypoxia induces transcription of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase-4 gene via hypoxia-inducible factor-1alpha activation. FEBS Lett 2004; 576:14-20. [PMID: 15474002 DOI: 10.1016/j.febslet.2004.08.053] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2004] [Revised: 07/15/2004] [Accepted: 08/30/2004] [Indexed: 12/14/2022]
Abstract
The PFKFB4 gene encodes isoenzyme of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase (PFKFB or PFK-2/FBPase-2) which originally was found in the testes. We have studied hypoxic regulation of PFKFB4 gene in prostate cancer cell line, PC-3, and several other cancer cell lines. It was shown that hypoxia significantly induced PFKFB4 mRNA levels in PC-3 as well as in HeLa, Hep3B and HepG2 cell lines. Hypoxia increased PFKFB4 protein levels also. Moreover, desferrioxamine and cobalt chloride, which are known to mimic hypoxia, also had a stimulatory effect on the expression of PFKFB4 mRNA. In order to investigate the mechanisms of hypoxic regulation of PFKFB4 gene expression, we used dimethyloxalylglycine, which has the ability to mimic effect of hypoxia by significant induction of hypoxia-inducible factor (HIF-1alpha) protein levels. Our studies showed that PFKFB4 mRNA expression in PC-3, HeLa, Hep3B and HepG2 cell lines was highly responsive to dimethyloxalylglycine, an inhibitor of HIF-1alpha hydroxylase enzymes, suggesting that the hypoxia responsiveness of this gene is regulated by HIF proteins. To better understand the hypoxic regulation of PFKFB4 gene expression, we isolated genomic DNA, which includes the promoter region of PFKFB4. Cell transfection, deletion and site-specific mutagenesis of the PFKFB4 promoter region indicates that hypoxic induction of PFKFB4 gene expression is mediated by the hypoxia-responsive element (HRE). These experiments identified a HRE 422-429 bp upstream from the translation start site. Thus, our results indicate that testis-specific form of PFKFB or PFK-2/FBPase-2 is also expressed in several cancer cell lines and that hypoxia induces transcription of PFKFB4 gene in these cell lines by HIF-1alpha dependent mechanism. HRE in 5'-promoter region of PFKFB4 gene mediates hypoxic induction of PFKFB4 gene transcription.
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Affiliation(s)
- Oleksandr Minchenko
- Department of Molecular Biology, Palladin Institute of Biochemistry, National Academy of Science of Ukraine, Kyiv 01601, Ukraine.
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17
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Lee YH, Li Y, Uyeda K, Hasemann CA. Tissue-specific structure/function differentiation of the liver isoform of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase. J Biol Chem 2003; 278:523-30. [PMID: 12379646 DOI: 10.1074/jbc.m209105200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The crystal structures of the human liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase in three different liganding states were determined and compared with those of the rat testis isozyme. A set of amino acid sequence heterogeneity from the two distinct genes encoding the two different tissue isozymes leads to both global and local conformational differences that may cause the differences in catalytic properties of the two isozymes. The sequence differences in a beta-hairpin loop in the kinase domain causes a translational shift of several hydrophobic interactions in the dimeric contact region, and its propagation to the domains interface results in a 5 degrees twist of the entire bisphosphatase domain relative to the kinase domain. The bisphosphatase domain twist allows the dimeric interactions between the bisphosphatase domains, which are negligible in the testis enzyme, and as a result, the conformational stability of the domain is increased. Sequence polymorphisms also confer small but significant structural dissimilarities in the substrate-binding loops, allowing the differentiated catalytic properties between the two different tissue-type isozymes. Whereas the polymorphic sequence at the bisphosphatase-active pocket suggests a more suitable substrate binding, a similar extent of sequence differences at the kinase-active pocket confers a different mechanism of substrates bindings to the kinase-active pocket. It includes the ATP-sensitive unwinding of the switch helix alpha5, which is a characteristic ATP-dependent conformational change in the testis form. The sequence-dependent structural difference disallows the liver kinase to follow the ATP-switch mechanism. Altogether these suggest that the liver isoform has structural features more appropriate for an elevated bisphosphatase activity, compared with that of the testis form. The structural predisposition for bisphosphatase activity in the liver isozyme is consistent with the liver-unique glucose metabolic pathway, gluconeogenesis.
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Affiliation(s)
- Yong-Hwan Lee
- Structural Biology Core, Molecular Biology, University of Missouri, Columbia, Missouri 65211, USA.
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18
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Hydroformylation of cyclopentenes, novel strategy for total synthesis of carba- d -fructofuranose. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)00153-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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19
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20
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Zhu Z, Ling S, Yang QH, Li L. Involvement of the chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase sequence His444-Arg-Glu-Arg in modulation of the bisphosphatase activity by its kinase domain. Biochem J 2001; 357:513-20. [PMID: 11439102 PMCID: PMC1221979 DOI: 10.1042/0264-6021:3570513] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The bisphosphatase activity of the hepatic bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase is repressed by its kinase domain, and regulated by cAMP-dependent protein kinase (PKA)-catalysed phosphorylation. In the present study, the mechanism by which the bisphosphatase activity is repressed by the kinase domain and regulated by phosphorylation was investigated. We found that truncation of the C-terminus of the enzyme by 25, but not 20, amino acids dramatically enhanced the catalytic rate of the bisphosphatase, abrogated the inhibition by the kinase domain, and eliminated the effect of PKA-mediated phosphorylation on activity. In addition, mutation of His444-Arg-Glu-Arg to Ala-Ala-Glu-Ala had similar effects as the deletion. Moreover, the mutations also significantly affected the phosphorylation-mediated regulation of the kinase activity of the enzyme. Furthermore, the mutations altered the pH-dependence of the bisphosphatase, and the mutant bisphosphatases were more sensitive to modification by diethyl pyrocarbonate and guanidine-induced inactivation than the wild-type enzyme. Taken together, these results demonstrate that the sequence His444-Arg-Glu-Arg plays a critical role in repression of the bisphosphatase activity by both the N-terminal kinase domain and the C-terminal tail itself. These results also explain the activation of the bisphosphatase activity by PKA-catalysed phosphorylation, by suggesting that phosphorylation may relieve the inhibitory effect of the kinase domain that is mediated by the three basic residues in this sequence.
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Affiliation(s)
- Z Zhu
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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21
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Yang QH, Zhu Z, Dong MQ, Ling S, Wu CL, Li L. Binding of ATP to the fructose-2,6-bisphosphatase domain of chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase leads to activation of its 6-phosphofructo-2-kinase. J Biol Chem 2001; 276:24608-13. [PMID: 11325970 DOI: 10.1074/jbc.m102366200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To understand the mechanism by which the activity of the 6-phosphofructo-2-kinase (6PF-2K) of chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase is stimulated by its substrate ATP, we studied two mutants of the enzyme. Mutation of either Arg-279, the penultimate basic residue within the Walker A nucleotide-binding fold in the bisphosphatase domain, or Arg-359 to Ala eliminated the activation of the chicken 6PF-2K by ATP. Binding analysis by fluorescence spectroscopy using 2'(3')-O-(N-methylanthraniloyl)-ATP revealed that the kinase domains of these two mutants, unlike that of the wild type enzyme, showed no cooperativity in ATP binding and that the mutant enzymes possess only the high affinity ATP binding site, suggesting that the ATP binding site on the bisphosphatase domain represents the low affinity site. This conclusion was supported by the result that the affinity of ATP for the isolated bisphosphatase domain is similar to that for the low affinity site in the wild type enzyme. In addition, we found that the 6PF-2K of a chimeric enzyme, in which the last 25 residues of chicken enzyme were replaced with those of the rat enzyme, could not be activated by ATP, despite the fact that the ATP-binding properties of this chimeric enzyme were not different from those of the wild type chicken enzyme. These results demonstrate that activation of the chicken 6PF-2K by ATP may result from allosteric binding of ATP to the bisphosphatase domain where residues Arg-279 and Arg-359 are critically involved and require specific C-terminal sequences.
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Affiliation(s)
- Q H Yang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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22
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Navarro-Sabaté A, Manzano A, Riera L, Rosa JL, Ventura F, Bartrons R. The human ubiquitous 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase gene (PFKFB3): promoter characterization and genomic structure. Gene 2001; 264:131-8. [PMID: 11245987 DOI: 10.1016/s0378-1119(00)00591-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A DNA fragment containing 1.5 kb of the 5'-flanking region of the human ubiquitous PFKFB3 gene, coding for 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase, was cloned and its promoter activity was examined. The 5' flanking region contains a TATA box-like and GC-rich sequences, yielding several potential Specific protein (Sp-1) and activator protein (AP)-2 binding sites. Putative regulatory motifs for E-box, nuclear factor (NF)-1 and progesterone response element were also found by computer assisted analysis. Transient expression assays of truncated promoter-reporter constructs in HeLa cells showed that this gene is induced by phorbol esters (PDB) and cyclic-AMP-dependent protein kinase signal activation. Furthermore, the genomic organization of the PFKFB3 gene is reported. This gene spans more than 26 kb containing at least 16 exons that accounts for the two reported isoforms, inducible and ubiquitous, generated through alternative splicing of exon 15.
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Affiliation(s)
- A Navarro-Sabaté
- Unitat de Bioquímica. Departament de Ciències Fisiològiques II, Campus de Bellvitge, Universitat de, C/ Feixa Llarga s/n E-08907 L'Hospitalet, Barcelona, Spain
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23
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Raamsdonk LM, Teusink B, Broadhurst D, Zhang N, Hayes A, Walsh MC, Berden JA, Brindle KM, Kell DB, Rowland JJ, Westerhoff HV, van Dam K, Oliver SG. A functional genomics strategy that uses metabolome data to reveal the phenotype of silent mutations. Nat Biotechnol 2001; 19:45-50. [PMID: 11135551 DOI: 10.1038/83496] [Citation(s) in RCA: 636] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A large proportion of the 6,000 genes present in the genome of Saccharomyces cerevisiae, and of those sequenced in other organisms, encode proteins of unknown function. Many of these genes are "silent, " that is, they show no overt phenotype, in terms of growth rate or other fluxes, when they are deleted from the genome. We demonstrate how the intracellular concentrations of metabolites can reveal phenotypes for proteins active in metabolic regulation. Quantification of the change of several metabolite concentrations relative to the concentration change of one selected metabolite can reveal the site of action, in the metabolic network, of a silent gene. In the same way, comprehensive analyses of metabolite concentrations in mutants, providing "metabolic snapshots," can reveal functions when snapshots from strains deleted for unstudied genes are compared to those deleted for known genes. This approach to functional analysis, using comparative metabolomics, we call FANCY-an abbreviation for functional analysis by co-responses in yeast.
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Affiliation(s)
- L M Raamsdonk
- Swammerdam Institute for Life Sciences, BioCentrum Amsterdam, University of Amsterdam, Plantage Muidergracht 12, NL-1018 TV Amsterdam, The Netherlands
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24
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Zhu Z, Ling S, Yang QH, Li L. The difference in the carboxy-terminal sequence is responsible for the difference in the activity of chicken and rat liver fructose-2,6-bisphosphatase. Biol Chem 2000; 381:1195-202. [PMID: 11209754 DOI: 10.1515/bc.2000.147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The fructose-2,6-bisphosphatase domain of the bifunctional chicken liver enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase shares approximately 95% amino acid sequence homology with that of the rat enzyme. However, these two enzymes are significantly different in their phosphatase activities. In this report, we show that the COOH-terminal 25 amino acids of the two enzymes are responsible for the different enzymatic activities. Although these 25 amino acids are not required for the phosphatase activity, their removal diminishes the differences in the activities between the two enzymes. In addition, two chimeric molecules (one consisting of the catalytic core of the chicken bisphosphatase domain and the rat COOH-terminal 25 amino acids, and the other consisting of most of the intact chicken enzyme and the rat COOH-terminal 25 amino acids) showed the same kinetic properties as the rat enzyme. Furthermore, substitution of the residues Pro456Pro457Ala458 of the chicken enzyme with GluAlaGlu, the corresponding sequence in the rat liver enzyme, yields a chicken enzyme that behaves like the rat enzyme. These results demonstrate that the different bisphosphatase activities of the chicken and rat liver bifunctional enzymes can be attributed to the differences in their COOH-terminal amino acid sequences, particularly the three residues.
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Affiliation(s)
- Z Zhu
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences
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25
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Benigni F, Atsumi T, Calandra T, Metz C, Echtenacher B, Peng T, Bucala R. The proinflammatory mediator macrophage migration inhibitory factor induces glucose catabolism in muscle. J Clin Invest 2000; 106:1291-300. [PMID: 11086030 PMCID: PMC381433 DOI: 10.1172/jci9900] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Severe infection or tissue invasion can provoke a catabolic response, leading to severe metabolic derangement, cachexia, and even death. Macrophage migration inhibitory factor (MIF) is an important regulator of the host response to infection. Released by various immune cells and by the anterior pituitary gland, MIF plays a critical role in the systemic inflammatory response by counterregulating the inhibitory effect of glucocorticoids on immune-cell activation and proinflammatory cytokine production. We describe herein an unexpected role for MIF in the regulation of glycolysis. The addition of MIF to differentiated L6 rat myotubes increased synthesis of fructose 2,6-bisphosphate (F2,6BP), a positive allosteric regulator of glycolysis. Increased expression of the enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2) enhanced F2,6BP production and, consequently, cellular lactate production. The catabolic effect of TNF-alpha on myotubes was mediated by MIF, which served as an autocrine stimulus for F2, 6BP production. TNF-alpha administered to mice decreased serum glucose levels and increased muscle F2,6BP levels; pretreatment with a neutralizing anti-MIF mAb completely inhibited these effects. Anti-MIF also prevented hypoglycemia and increased muscle F2,6BP levels in TNF-alpha-knockout mice that were administered LPS, supporting the intrinsic contribution of MIF to these inflammation-induced metabolic changes. Taken together with the recent finding that MIF is a positive, autocrine stimulator of insulin release, these data suggest an important role for MIF in the control of host glucose disposal and carbohydrate metabolism.
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Affiliation(s)
- F Benigni
- The Picower Institute for Medical Research, Manhasset, New York 10030, USA
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26
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Peralta C, Bartrons R, Riera L, Manzano A, Xaus C, Gelpí E, Roselló-Catafau J. Hepatic preconditioning preserves energy metabolism during sustained ischemia. Am J Physiol Gastrointest Liver Physiol 2000; 279:G163-71. [PMID: 10898759 DOI: 10.1152/ajpgi.2000.279.1.g163] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We evaluated the possibility that ischemic preconditioning could modify hepatic energy metabolism during ischemia. Accordingly, high-energy nucleotides and their degradation products, glycogen and glycolytic intermediates and regulatory metabolites, were compared between preconditioned and nonpreconditioned livers. Preconditioning preserved to a greater extent ATP, adenine nucleotide pool, and adenylate energy charge; the accumulation of adenine nucleosides and bases was much lower in preconditioned livers, thus reflecting slower adenine nucleotide degradation. These effects were associated with a decrease in glycogen depletion and reduced accumulation of hexose 6-phosphates and lactate. 6-Phosphofructo-2-kinase decreased in both groups, reducing the availability of fructose-2, 6-bisphosphate. Preconditioning sustained metabolite concentration at higher levels although this was not correlated with an increased glycolytic rate, suggesting that adenine nucleotides and cAMP may play the main role in the modulation of glycolytic pathway. Preconditioning attenuated the rise in cAMP and limited the accumulation of hexose 6-phosphates and lactate, probably by reducing glycogen depletion. Our results suggest the induction of metabolic arrest and/or associated metabolic downregulation as energetic cost-saving mechanisms that could be induced by preconditioning.
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Affiliation(s)
- C Peralta
- Unitat de Bioquímica, Campus de Bellvitge, Universitat de Barcelona, Spain
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27
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Goren N, Manzano A, Riera L, Ambrosio S, Ventura F, Bartrons R. 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase expression in rat brain during development. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2000; 75:138-42. [PMID: 10648897 DOI: 10.1016/s0169-328x(99)00319-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This study reports the expression of the ubiquitous 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase gene (PFKFB3) (PFK-2/FBPase-2) in different stages of rat brain development. Northern blot and RT-PCR analysis demonstrated that ubiquitous PFK-2/FBPase-2 is expressed in rat brain from embryonic to adult life and shows a transient increase 1 day before birth, coincident with the maximum concentration of Fru-2,6-P(2) and PFK-2 activity. The levels of brain PFK-2/FBPase-2 gene expression as well as the enzymatic activity and the concentration of Fru-2,6-P(2) appear to be remarkably constant during adult life, without significant differences in the brain hippocampus, cortex, cerebellum or striatum areas.
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Affiliation(s)
- N Goren
- Cátedra de Farmacología, Facultad de Odontología, Universidad de Buenos Aires, CEFYBO-CONICET, Buenos Aires, Argentina
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28
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Kholodenko BN, Westerhoff HV, Schwaber J, Cascante M. Engineering a living cell to desired metabolite concentrations and fluxes: pathways with multifunctional enzymes. Metab Eng 2000; 2:1-13. [PMID: 10935931 DOI: 10.1006/mben.1999.0132] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
With molecular genetics enabling modulation of the concentrations of cellular enzymes, metabolic engineering becomes limited by the question of which modulations of the enzyme concentrations are required to bring about a desired pattern of cellular metabolism. In an earlier paper (Kholodenko et al. (1998). Biotechnol. Bioeng. 59, 239-247) we derived a method to determine the required modulations. This method, however, cannot be immediately applied to cellular pathways with enzymes catalyzing more than one step in metabolism (multifunctional enzymes). In the present paper we show to which extent the presence of multifunctional enzymes limits biotechological ambitions, which one might otherwise pursue in vain. In particular, it is impossible to change the concentration of a single intermediate and leave the rest of metabolism unperturbed if that intermediate interacts directly with a multifunctional enzyme. The analytical machinery of Metabolic Control Analysis is used to relate the desired and ensuing changes in the metabolic pattern. An explicit solution to this problem of engineering metabolism is then given in the form of a single matrix equation.
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Affiliation(s)
- B N Kholodenko
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
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29
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Ainscow EK, Brand MD. Internal regulation of ATP turnover, glycolysis and oxidative phosphorylation in rat hepatocytes. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 266:737-49. [PMID: 10583367 DOI: 10.1046/j.1432-1327.1999.00856.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Previously [Ainscow, E.K. & Brand, M.D. (1999) Eur. J. Biochem. 263, 671-685], top-down control analysis was used to describe the control pattern of energy metabolism in rat hepatocytes. The system was divided into nine reaction blocks (glycogen breakdown, glucose release, glycolysis, lactate production, NADH oxidation, pyruvate oxidation, mitochondrial proton leak, mitochondrial phosphorylation and ATP consumption) linked by five intermediates (intracellular glucose 6-phosphate, pyruvate and ATP levels, cytoplasmic NADH/NAD ratio and mitochondrial membrane potential). The kinetic responses (elasticities) of reaction blocks to intermediates were determined and used to calculate control coefficients. In the present paper, these elasticities and control coefficients are used to quantify the internal regulatory pathways within the cell. Flux control coefficients were partitioned to give partial flux control coefficients. These describe how strongly one block of reactions controls the flux through another via its effects on the concentration of a particular intermediate. Most flux control coefficients were the sum of positive and negative partial effects acting through different intermediates; these partial effects could be large compared to the final control strength. An important result was the breakdown of the way ATP consumption controlled respiration: changes in ATP level were more important than changes in mitochondrial membrane potential in stimulating oxygen consumption when ATP consumption increased. The partial internal response coefficients to changes in each intermediate were also calculated; they describe how steady state concentrations of intermediates are maintained. Increases in mitochondrial membrane potential were opposed mostly by decreased supply, whereas increases in glucose-6-phosphate, NADH/NAD and pyruvate were opposed mostly by increased consumption. Increases in ATP were opposed significantly by both decreased supply and increased consumption.
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Affiliation(s)
- E K Ainscow
- Department of Biochemistry, University of Cambridge. UK
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30
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Seepersaud M, Al-Abed Y. Total Synthesis of Carba-d-fructofuranose via a Novel Metathesis Reaction. Org Lett 1999. [DOI: 10.1021/ol990275n] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mohindra Seepersaud
- The Picower Institute for Medical Research, 350 Community Drive, Manhasset, New York 11030
| | - Yousef Al-Abed
- The Picower Institute for Medical Research, 350 Community Drive, Manhasset, New York 11030
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31
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Pierreux CE, Stafford J, Demonte D, Scott DK, Vandenhaute J, O'Brien RM, Granner DK, Rousseau GG, Lemaigre FP. Antiglucocorticoid activity of hepatocyte nuclear factor-6. Proc Natl Acad Sci U S A 1999; 96:8961-6. [PMID: 10430878 PMCID: PMC17715 DOI: 10.1073/pnas.96.16.8961] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Glucocorticoids exert their effects on gene transcription through ubiquitous receptors that bind to regulatory sequences present in many genes. These glucocorticoid receptors are present in all cell types, yet glucocorticoid action is controlled in a tissue-specific way. One mechanism for this control relies on tissue-specific transcriptional activators that bind in the vicinity of the glucocorticoid receptor and are required for receptor action. We now describe a gene-specific and tissue-specific inhibitory mechanism through which glucocorticoid action is repressed by a tissue-restricted transcription factor, hepatocyte nuclear factor-6 (HNF-6). HNF-6 inhibits the glucocorticoid-induced stimulation of two genes coding for enzymes of liver glucose metabolism, namely 6-phosphofructo-2-kinase and phosphoenolpyruvate carboxykinase. Binding of HNF-6 to DNA is required for inhibition of glucocorticoid receptor activity. In vitro and in vivo experiments suggest that this inhibition is mediated by a direct HNF-6/glucocorticoid receptor interaction involving the amino-terminal domain of HNF-6 and the DNA-binding domain of the receptor. Thus, in addition to its known property of stimulating transcription of liver-expressed genes, HNF-6 can antagonize glucocorticoid-stimulated gene transcription.
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Affiliation(s)
- C E Pierreux
- Hormone and Metabolic Research Unit, Université catholique de Louvain and Christian de Duve Institute of Cellular Pathology, 75 Avenue Hippocrate, B-1200 Brussels, Belgium
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32
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Vandoolaeghe P, Gueuning MA, Rousseau GG. M-type 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase is the product of a late muscle differentiation gene. Biochem Biophys Res Commun 1999; 259:250-4. [PMID: 10362495 DOI: 10.1006/bbrc.1999.0767] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Genes that are expressed in adult muscle, but not in myotubes, are useful markers of the last steps of muscle maturation. We have investigated at what stage of differentiation the muscle-specific (M) promoter of a gene that codes for 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK2) becomes functional. M-PFK2 mRNA, which is present in adult muscle, did not appear during differentiation of L6 myoblasts into myotubes induced by growth factor withdrawal and hormonal treatment, even when this differentiation was stimulated by expression of transgenes coding for myf-5 or Rb. A comparison with the expression pattern of muscle genes showed that M-PFK2 is a marker of mature skeletal muscle. We also found that M-PFK2 is expressed in both types (slow-twitch and fast-twitch) of adult muscle. Thus, the M-PFK2 promoter is a novel model for studying the transcriptional control of the final steps of muscle differentiation that are common to the two types of myofibers.
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Affiliation(s)
- P Vandoolaeghe
- Hormone and Metabolic Research Unit, Université catholique de Louvain and Christian de Duve Institute of Cellular Pathology (ICP), 75 Avenue Hippocrate, Brussels, B-1200, Belgium
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Durante P, Gueuning MA, Darville MI, Hue L, Rousseau GG. Apoptosis induced by growth factor withdrawal in fibroblasts overproducing fructose 2,6-bisphosphate. FEBS Lett 1999; 448:239-43. [PMID: 10218483 DOI: 10.1016/s0014-5793(99)00387-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Fructose 2,6-bisphosphate is a potent endogenous stimulator of glycolysis. A high aerobic glycolytic rate often correlates with increased cell proliferation. To investigate this relationship, we have produced clonal cell lines of Rat-1 fibroblasts that stably express transgenes coding for 6-phosphofructo-2-kinase, which catalyzes the synthesis of fructose 2,6-bisphosphate, or for fructose 2,6-bisphosphatase, which catalyzes its degradation. While serum deprivation in culture reduced the growth rate of control cells, it caused apoptosis in cells overproducing fructose 2,6-bisphosphate. Apoptosis was inhibited by 5-amino-4-imidazolecarboxamide riboside, suggesting that 5'-AMP-activated protein kinase interferes with this phenomenon.
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Affiliation(s)
- P Durante
- Hormone and Metabolic Research Unit, Université Catholique de Louvain and Christian de Duve Institute of Cellular Pathology, Brussels, Belgium
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34
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Manzano A, Pérez JX, Nadal M, Estivill X, Lange A, Bartrons R. Cloning, expression and chromosomal localization of a human testis 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase gene. Gene 1999; 229:83-9. [PMID: 10095107 DOI: 10.1016/s0378-1119(99)00037-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
6-Phosphofructo-2-kinase/fructose 2,6-bisphosphatase (PFK-2/FBPase-2) is a bifunctional enzyme responsible for the synthesis and breakdown of Fru-2,6-P2, a key metabolite in the regulation of glycolysis. Several genes encode distinct PFK-2/FBPase-2 isozymes that differ in their tissue distribution and enzyme regulation. In this paper, we present the isolation of a cDNA from a human testis cDNA library that encodes a PFK-2/FBPase-2 isozyme. Sequencing data show an open reading frame of 1407 nucleotides that codifies for a protein of 469 amino acids. This has a calculated molecular weight of 54kDa and 97% similarity with rat testis PFK-2/FBPase-2, with complete conservation of the amino acid residues involved in the catalytic mechanism. Fluorescence in-situ hybridization (FISH) localized testis PFK-2/FBPase-2 gene (PFKFB4) in human chromosome 3 at bands p21-p22. A Northern blot analysis of different rat tissues showed the presence of a 2.4-kb mRNA expressed specifically in testis. In mammalian COS-1 cells, the human testis cDNA drives expression of an isozyme with a molecular weight of 55kDa. This isozyme shows clear PFK-2 activity. Taken together, these results provide evidence for a new PFK-2/FBPase-2 gene coding for a human testis isozyme.
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Affiliation(s)
- A Manzano
- Unitat de Bioquímica, Campus de Bellvitge, U.B.C/Feixa Llarga sn E-08907, L'Hospitalet, Spain
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Bruni P, Vandoolaeghe P, Rousseau GG, Hue L, Rider MH. Expression and regulation of 6-phosphofructo-2-kinase/fructose- 2,6-bisphosphatase isozymes in white adipose tissue. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 259:756-61. [PMID: 10092861 DOI: 10.1046/j.1432-1327.1999.00104.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The aim of this work was to identify the 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2) isozyme(s) present in white adipose tissue. Ion-exchange chromatography of PFK-2 from rat epididymal fat pads yielded an elution pattern compatible with the presence of both the L (liver) and M (muscle) isozymes. This was consistent with a study of the phosphorylation of the purified adipose tissue enzyme by cAMP-dependent protein kinase, by specific labelling of the preparation with [2-32P]fructose 2,6-bisphosphate and by reaction with antibodies. Characterization of the PFK-2/FBPase-2 mRNAs showed that mature adipocytes express the mRNA that codes for the L isozyme and the two mRNAs that code for the M isozyme. Preadipocytes expressed mRNA that codes for the M isozyme. Incubation of rat epididymal fat pads with adrenaline stimulated glycolysis but decreased fructose 2,6-bisphosphate concentrations without significant inactivation of PFK-2. These results support previous findings showing that fructose 2,6-bisphosphate is not involved in the adrenaline-induced stimulation of glycolysis in white adipose tissue.
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Affiliation(s)
- P Bruni
- Hormone and Metabolic Research Unit, Louvain University Medical School, Brussels, Belgium
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Yuen MH, Mizuguchi H, Lee YH, Cook PF, Uyeda K, Hasemann CA. Crystal structure of the H256A mutant of rat testis fructose-6-phosphate,2-kinase/fructose-2,6-bisphosphatase. Fructose 6-phosphate in the active site leads to mechanisms for both mutant and wild type bisphosphatase activities. J Biol Chem 1999; 274:2176-84. [PMID: 9890980 DOI: 10.1074/jbc.274.4.2176] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fructose-6-phosphate,2-kinase/fructose-2,6-bisphosphatase (Fru-6-P, 2-kinase/Fru-2,6-Pase) is a bifunctional enzyme, catalyzing the interconversion of beta-D-fructose- 6-phosphate (Fru-6-P) and fructose-2,6-bisphosphate (Fru-2,6-P2) at distinct active sites. A mutant rat testis isozyme with an alanine replacement for the catalytic histidine (H256A) in the Fru-2,6-Pase domain retains 17% of the wild type activity (Mizuguchi, H., Cook, P. F., Tai, C-H., Hasemann, C. A., and Uyeda, K. (1998) J. Biol. Chem. 274, 2166-2175). We have solved the crystal structure of H256A to a resolution of 2. 4 A by molecular replacement. Clear electron density for Fru-6-P is found at the Fru-2,6-Pase active site, revealing the important interactions in substrate/product binding. A superposition of the H256A structure with the RT2K-Wo structure reveals no significant reorganization of the active site resulting from the binding of Fru-6-P or the H256A mutation. Using this superposition, we have built a view of the Fru-2,6-P2-bound enzyme and identify the residues responsible for catalysis. This analysis yields distinct catalytic mechanisms for the wild type and mutant proteins. The wild type mechanism would lead to an inefficient transfer of a proton to the leaving group Fru-6-P, which is consistent with a view of this event being rate-limiting, explaining the extremely slow turnover (0. 032 s-1) of the Fru-2,6-Pase in all Fru-6-P,2-kinase/Fru-2,6-Pase isozymes.
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Affiliation(s)
- M H Yuen
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA
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37
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Hirata T, Kato M, Okamura N, Fukasawa M, Sakakibara R. Expression of human placental-type 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase in various cells and cell lines. Biochem Biophys Res Commun 1998; 242:680-4. [PMID: 9464277 DOI: 10.1006/bbrc.1997.8024] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The expression of the human placental-type 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (HP2K) in various human cells and cell lines was investigated at the levels of transcription and translation. Analyses by both Northern blotting and a reverse transcription-polymerase chain reaction (RT-PCR) showed that BeWo, U-937, SupT1, H9, HeLa, HepG2, and human mononuclear cells, as well as human placental chorionic cells, expressed HP2K mRNA. All the nucleotide sequences of RT-PCR products from these cell lines were identical to that of HP2K. The expression of HP2K protein was determined by Western blot analysis of fractions from POROS-HQ column chromatography of the cell extracts from U-937 cells, which was used as an example of HP2K-mRNA positive cell lines. As with the 6-phosphofructo-2-kinase activity of HP2K, the activity of 6-phosphofructo-2-kinase in extracts of U-937 cells was not inhibited by glycerol 3-phosphate, a known 6-phosphofructo-2-kinase inhibitor of liver- and testis-type isozymes. These results strongly suggested that various cell lines, in particular U-937 cells, express functional HP2K enzyme. Furthermore, 6-phosphofructo-2-kinase in U-937 cells was found to be activated by treatments with isoproterenol and phorbol 12-myristate 13-acetate, indicating regulation of 6-phosphofructo-2-kinase activity in U-937 cells by protein kinases A and C.
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Affiliation(s)
- T Hirata
- Department of Biochemistry, School of Pharmaceutical Sciences, Nagasaki University, Japan
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38
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Landry C, Clotman F, Hioki T, Oda H, Picard JJ, Lemaigre FP, Rousseau GG. HNF-6 is expressed in endoderm derivatives and nervous system of the mouse embryo and participates to the cross-regulatory network of liver-enriched transcription factors. Dev Biol 1997; 192:247-57. [PMID: 9441665 DOI: 10.1006/dbio.1997.8757] [Citation(s) in RCA: 120] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Hepatocyte nuclear factor-6 (HNF-6) is a liver-enriched transcription factor that contains a single cut domain and a novel type of homeodomain. Here we have studied the developmental expression pattern of HNF-6 in the mouse. In situ hybridization experiments showed that HNF-6 mRNA is detected in the liver at embryonic day (E) 9, at the onset of liver differentiation. HNF-6 mRNA disappeared transiently from the liver between E12.5 and E15. In transfection experiments HNF-6 stimulated the expression of HNF-4 and of HNF-3 beta, two transcription factors known to be involved in liver development and differentiation. HNF-6 was detected in the pancreas from E10.5 onward, where it was restricted to the exocrine cells. HNF-6 was also detected in the developing nervous system. Both the brain and the spinal cord started to express HNF-6 at E9-9.5 in postmitotic neuroblasts. Later on, HNF-6 was restricted to brain nuclei, to the retina, to the ventral horn of the spinal cord, and to dorsal root ganglia. Our observations that HNF-6 contributes to the control of the expression of transcription factors and is expressed at early stages of liver, pancreas, and neuronal differentiation suggest that HNF-6 regulates several developmental programs.
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Affiliation(s)
- C Landry
- Hormone and Metabolic Research Unit, International Institute of Cellular and Molecular Pathology, Brussels, Belgium
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Li L, Ling S, Wu CL, Yao W, Xu G. Separate bisphosphatase domain of chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase: the role of the C-terminal tail in modulating enzyme activity. Biochem J 1997; 328 ( Pt 3):751-6. [PMID: 9396716 PMCID: PMC1218982 DOI: 10.1042/bj3280751] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The separate bisphosphatase domain (amino acid residues 243-468) of the chicken liver bifunctional enzyme 6-phosphofructo-2-kinase-fructose-2,6-bisphosphatase was expressed in Escherichia coli and purified to homogeneity. The fructose-2, 6-bisphosphatase activity of the separate domain was 7-fold higher than that of the native bifunctional enzyme, and exhibited substrate inhibition characteristic of the native enzyme. The inhibition of the enzymes by fructose 2,6-bisphosphate could be overcome by Pi, glycerol 3-phosphate and GTP. Deletion of 30 amino acid residues from the C-terminus of the separate domain resulted in around a 5-fold increase in the Vmax of the bisphosphatase. Also, the truncated form was more accessible to chemical modification by diethyl pyrocarbonate and N-ethylmaleimide, suggesting a more open structure than the wild-type form. In addition, the mutation of cysteine-389 to alanine increased bisphosphatase activity by 20% and the Km value for fructose 2,6-bisphosphate by 3-fold, and both the point mutation at cysteine-389 and the deletional mutation led to the predominantly insoluble expression of the enzyme. The results indicated that the C-terminal tail plays a role in modulating the enzyme activity and suggested that the difference in the C-terminal tail sequence is responsible for the difference in activity of the chicken and rat liver fructose-2,6-bisphosphatases. It is postulated that an interaction between the C-terminal tail and the active site might be present.
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Affiliation(s)
- L Li
- Shanghai Institute of Biochemistry, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
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40
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Dupriez VJ, Rousseau GG. Glucose response elements in a gene that codes for 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase. DNA Cell Biol 1997; 16:1075-85. [PMID: 9324310 DOI: 10.1089/dna.1997.16.1075] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We have shown previously that rat hepatoma FTO-2B cells express two mRNAs, called F (fetal) and L (liver), from distinct promoters of the same gene coding for 6-phosphofructo-2-kinase (PFK-2). This enzyme catalyzes the synthesis of fructose 2,6-bisphosphate, an allosteric stimulator of glycolysis. We have now found that glucose, as well as lactate and pyruvate, increases the concentration of the F and L mRNAs. The effect of glucose was mimicked by xylitol, a precursor of xylulose 5-phosphate, and hence of intermediates of the pentose phosphate and glycolytic pathways, and was inhibited by okadaic acid, an inhibitor of protein phosphatases. Transfection experiments showed that the F promoter region is a target of the glucose effect, with glucose stimulating F promoter activity in a way probably similar to mitogens. Another region of the gene, located between the F and L promoters, also behaved as a glucose-sensitive element. This region corresponds to a cluster of DNase I-hypersensitive sites that were induced in chromatin following glucose treatment. The sequence organization of this region is very similar to the functional architecture of the glucose-sensitive insulin gene promoter. We propose a model for the concerted regulation by glucose metabolites of three pathways that lead to increased PFK-2 activity.
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Affiliation(s)
- V J Dupriez
- Hormone and Metabolic Research Unit, Louvain University Medical School and International Institute of Cellular and Molecular Pathology, Brussels, Belgium
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41
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Vandoolaeghe P, Rousseau GG. C/EBP binds over the TATA box and can activate the M promoter of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase. Biochem Biophys Res Commun 1997; 232:247-50. [PMID: 9125141 DOI: 10.1006/bbrc.1997.6266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The gene A coding for 6-phosphofructo-2-kinase gives rise to three mRNA that originate from distinct promoters called F (fetal), M (muscle) and L (liver). The regulation of the M promoter is ill-understood and its TATA box region binds an unidentified factor. The aim of this work was to identify this factor and to investigate its activity. In vitro protein-DNA binding assays and transfection experiments showed that this factor is C/EBP and that C/EBP can stimulate the M promoter despite its potential interference with TFIID binding. The effect of C/EBP was abolished by a dominant negative variant of C/EBP. These data and other work lead to the conclusion that C/EBP may participate to the regulation of promoter switching in 6-phosphofructo-2-kinase gene A.
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Affiliation(s)
- P Vandoolaeghe
- Hormone and Metabolic Research Unit, International Institute of Cellular and Molecular Pathology, Brussels, Belgium
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42
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Hasemann CA, Istvan ES, Uyeda K, Deisenhofer J. The crystal structure of the bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase reveals distinct domain homologies. Structure 1996; 4:1017-29. [PMID: 8805587 DOI: 10.1016/s0969-2126(96)00109-8] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Glucose homeostasis is maintained by the processes of glycolysis and gluconeogenesis. The importance of these pathways is demonstrated by the severe and life threatening effects observed in various forms of diabetes. The bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase catalyzes both the synthesis and degradation of fructose-2,6-bisphosphate, a potent regulator of glycolysis. Thus this bifunctional enzyme plays an indirect yet key role in the regulation of glucose metabolism. RESULTS We have determined the 2.0 A crystal structure of the rat testis isozyme of this bifunctional enzyme. The enzyme is a homodimer of 55 kDa subunits arranged in a head-to-head fashion, with each monomer consisting of independent kinase and phosphatase domains. The location of ATPgammaS and inorganic phosphate in the kinase and phosphatase domains, respectively, allow us to locate and describe the active sites of both domains. CONCLUSIONS The kinase domain is clearly related to the superfamily of mononucleotide binding proteins, with a particularly close relationship to the adenylate kinases and the nucleotide-binding portion of the G proteins. This is in disagreement with the broad speculation that this domain would resemble phosphofructokinase. The phosphatase domain is structurally related to a family of proteins which includes the cofactor independent phosphoglycerate mutases and acid phosphatases.
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Affiliation(s)
- C A Hasemann
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75235-8884, USA.
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43
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Lemaigre FP, Durviaux SM, Truong O, Lannoy VJ, Hsuan JJ, Rousseau GG. Hepatocyte nuclear factor 6, a transcription factor that contains a novel type of homeodomain and a single cut domain. Proc Natl Acad Sci U S A 1996; 93:9460-4. [PMID: 8790352 PMCID: PMC38450 DOI: 10.1073/pnas.93.18.9460] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Tissue-specific transcription is regulated in part by cell type-restricted proteins that bind to defined sequences in target genes. The DNA-binding domain of these proteins is often evolutionarily conserved. On this basis, liver-enriched transcription factors were classified into five families. We describe here the mammalian prototype of a sixth family, which we therefore call hepatocyte nuclear factor 6 (HNF-6). It activates the promoter of a gene involved in the control of glucose metabolism. HNF-6 contains two different DNA-binding domains. One of these corresponds to a novel type of homeodomain. The other is homologous to the Drosophila cut domain. A similar bipartite sequence is coded by the genome of Caenorhabditis elegans.
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Affiliation(s)
- F P Lemaigre
- Hormone and Metabolic Research Unit, International Institute of Cellular and Molecular Pathology, Brussels, Belgium
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Aldea M, Piedrafita L, Casas C, Casamayor A, Khalid H, Balcells L, Ariño J, Herrero E. Sequence analysis of a 12 801 bp fragment of the left arm of yeast chromosome XV containing a putative 6-phosphofructo-2-kinase gene, a gene for a possible glycophospholipid-anchored surface protein and six other open reading frames. Yeast 1996; 12:1053-8. [PMID: 8896270 DOI: 10.1002/(sici)1097-0061(199609)12:10b%3c1053::aid-yea993%3e3.0.co;2-s] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The DNA sequence of a 12,801 bp fragment located near the left telomere of chromosome XV has been determined. Sequence analysis reveals eight open reading frames (ORFs) encoding polypeptides larger than 100 residues. ORFs AOE129 and AOAA121 are in opposite strands and they overlap at their 3' ends. AOE397 has similarity with phosphofructokinase genes from other organisms and may code for a second 6-phosphofructo-2-kinase of Saccharomyces cerevisiae. Sequence of AOA471 shows significant similarity with yeast genes coding for glycophospholipid-containing proteins. AOD1341 would code for a 1341 amino acids long protein with a predicted ATP/GTP-binding site and a transmembrane domain.
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Affiliation(s)
- M Aldea
- Departament de Ciències Mèdiques Bàsiques, Facultat de Medicina, Universitat de Lleida, Spain
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Aldea M, Piedrafita L, Casas C, Casamayor A, Khalid H, Balcells L, Ariño J, Herrero E. Sequence analysis of a 12 801 bp fragment of the left arm of yeast chromosome XV containing a putative 6-phosphofructo-2-kinase gene, a gene for a possible glycophospholipid-anchored surface protein and six other open reading frames. Yeast 1996. [DOI: 10.1002/(sici)1097-0061(199609)12:10b<1053::aid-yea993>3.0.co;2-s] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Boles E, Göhlmann HW, Zimmermann FK. Cloning of a second gene encoding 5-phosphofructo-2-kinase in yeast, and characterization of mutant strains without fructose-2,6-bisphosphate. Mol Microbiol 1996; 20:65-76. [PMID: 8861205 DOI: 10.1111/j.1365-2958.1996.tb02489.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We have identified a new gene, PFK27, that encodes a second inducible 6-phosphofructo-2-kinase in the yeast Saccharomyces cerevisiae. Sequencing shows an open reading frame of 397 amino acids and 45.3 kDa. Amino acid sequence comparisons with other bifunctional 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase isoenzymes of various organisms revealed similarities only to the kinase domains. Expression of PFK27 was induced severalfold by glucose and sucrose, but not by galactose or maltose, suggesting that sugar transport might be involved in triggering the induction signal. We have constructed a mutant strain devoid of any fructose-2,6-bisphosphate. The mutant strain grew well on several kinds and concentrations of carbon sources. The levels of hexose phosphates in the cells were increased, but flux rates for glucose utilization and ethanol production were similar to the wild-type strain. However, after the transfer of the mutant cells from respiratory to fermentative growth conditions, growth, glucose consumption and ethanol production were delayed in a transition phase. Our results show that fructose-2,6-bisphosphate is an important effector in vivo of the 6-phosphofructo-1-kinase/fructose-1 ,6-bisphosphatase enzyme pair, and is involved in the initiation of glycolysis during the transition to a fermentative mode of metabolism. Nevertheless, it can be effectively replaced by other effectors and regulatory mechanisms during growth on glucose.
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Affiliation(s)
- E Boles
- Institut für Mikrobiologie und Genetik, Technische Hochschule Darmstadt, Germany
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Casado M, Boscá L, Martín-Sanz P. Multiple forms of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase are expressed in perinatal rat liver. Am J Physiol Endocrinol Metab 1996; 270:E244-50. [PMID: 8779945 DOI: 10.1152/ajpendo.1996.270.2.e244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Fetal rat liver expresses a 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/Fru-2,6-Pase2) form that differs from the adult liver enzyme in the inhibition by phosphorylation by the adenosine 3',5'-cyclic monophosphate-dependent protein kinase and in the recognition by an antibody specific for the NH2-terminal domain of the adult liver enzyme. Northern blot analysis shows that fetal hepatocytes contain a species of mRNA that is 2.2 kb in size and that exhibits the maximal levels after delivery. PFK-2/Fru-2,6-Pase2 mRNA analysis using a sensitive ribonuclease protection assay reveals the presence of nearly similar amounts of adult liver-specific and skeletal muscle-specific mRNA in fetal liver and hepatocytes during the last days of gestation, as well as a 233-bp protected fragment present in fetal liver. These results were confirmed by polymerase chain reaction using specific oligonucleotide pairs. Primer extension of fetal liver cDNA suggests the presence of two initiation sites of transcription. Analysis of the adult liver PFK-2/Fru-2,6-Pase2 protein during the perinatal transition using a specific antibody shows a marked accumulation of this form immediately after birth.
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Affiliation(s)
- M Casado
- Facultad de Farmacia, Instituto de Bioquímica, Consejo Superior de Investigaciones Científicas-Universidad Complutense, Madrid, Spain
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Abstract
Gluconeogenesis, or the formation of glucose from mainly lactate/ pyruvate, glycerol and alanine, plays an essential role in the maintenance of normoglycaemia during fasting. Inborn deficiencies are known of each of the four enzymes of the glycolytic-gluconeogenic pathway that ensure a unidirectional flux from pyruvate to glucose: pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase, and glucose-6-phosphatase. In this paper, the clinical picture, pathophysiology, diagnostic tests, genetics, treatment and prognosis of the deficiencies of fructose-1,6-bisphosphatase and phosphoenolpyruvate carboxykinase are reviewed.
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Affiliation(s)
- G van den Berghe
- Laboratory of Physiological Chemistry, International Institute of Cellular and Molecular Pathology, Brussels, Belgium
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Casado M, Boscá L, Martín-Sanz P. Differential regulation of the expression of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase and pyruvate kinase by cyclic adenosine 3',5'-monophosphate in fetal and adult hepatocytes. J Cell Physiol 1995; 165:630-8. [PMID: 7593243 DOI: 10.1002/jcp.1041650322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Incubation of fetal hepatocytes from 21-day-old rats with permeant derivatives of cyclic AMP (cAMP) or glucagon, increased the mRNA levels of 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase (PFK-2/FBPase-2), L-pyruvate kinase (L-PK) and phosphoenolpyruvate carboxykinase (PEPCK). Contrary to this behavior, adult hepatocytes exhibited a decrease in the PFK-2/FBPase-2 and L-PK mRNA levels when incubated under equivalent experimental conditions. Dexamethasone also increased the PFK-2/FBPase-2 mRNA levels and costimulation of fetal hepatocytes with dexamethasone and a permeant analogue of cyclic AMP enhanced the levels of PFK-2/FBPase-2 mRNA, a situation opposite to that exhibited by adult hepatocytes. Treatment of the hepatocytes with transcriptional and translational inhibitors also produced differential responses in both types of cells. The PFK-2/FBPase-2 mRNA in fetal hepatocytes was more stable than in the adult cells. These results suggest that specific transcriptional factors and regulatory pathways differentially operate in fetal and adult hepatocytes in the control of the responses of carbohydrate metabolism to cAMP.
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Affiliation(s)
- M Casado
- Instituto de Bioquímica (CSIC-UCM), Facultad de Farmacia, Madrid, Spain
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Nissler K, Petermann H, Wenz I, Brox D. Fructose 2,6-bisphosphate metabolism in Ehrlich ascites tumour cells. J Cancer Res Clin Oncol 1995; 121:739-45. [PMID: 7499445 DOI: 10.1007/bf01213320] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Cancer cell energy metabolism is characterized by a high glycolytic rate, which is maintained under aerobic conditions. In Ehrlich ascites tumour cells, the concentration of fructose 2,6-bisphosphate (Fru-2,6-P2), the powerful activator of 6-phosphofructo-1-kinase, is tenfold increased. The bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2), synthesizing and degrading Fru-2,6-P2, was characterized. The molecular mass is 120 kDa. The dependence of PFK-2 activity on the substrate concentrations is hyperbolic (Km for Fru-6-P = 0.09 mM; Km for ATP = 0.7 mM), while the dependence of the FBPase-2 activity on the concentrations of Fru-2,6-P2 is sigmoidal (K0.5 for Fru-2,6-P2 = 4 microM). The PFK-2/FBPase-2 activity ratio is 1. PFK-2 activity is inhibited by citrate (I0.5 = 0.17 mM) and phosphoenolpyruvate (I0.5 = 0.08 mM) but only weakly by glycerol 3-phosphate (I0.5 = 1.57 mM). In contrast to the liver enzyme, the activity of tumour PFK-2/FBPase-2 is not influenced by the action of cAMP-dependent protein kinase. The kinetic properties as well as ion-exchange chromatography pattern differ from their normal counterparts in liver and muscle. The properties are likely to contribute to the maintenance of the high glycolytic rate in these tumour cells.
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Affiliation(s)
- K Nissler
- Institute of Biochemistry, Medical Faculty, Friedrich Schiller University, Jena, Germany
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