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Rani R, Syngkli S, Nongkhlaw J, Das B. Expression and characterisation of human glycerol kinase: the role of solubilising agents and molecular chaperones. Biosci Rep 2023; 43:BSR20222258. [PMID: 37021775 PMCID: PMC10130975 DOI: 10.1042/bsr20222258] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/11/2023] [Accepted: 04/06/2023] [Indexed: 04/07/2023] Open
Abstract
BACKGROUND Glycerol kinase (GK; EC 2.7.1.30) facilitates the entry of glycerol into pathways of glucose and triglyceride metabolism and may play a potential role in Type 2 diabetes mellitus (T2DM). However, the detailed regulatory mechanisms and structure of the human GK are unknown. METHODS The human GK gene was cloned into the pET-24a(+) vector and over-expressed in Escherichia coli BL21 (DE3). Since the protein was expressed as inclusion bodies (IBs), various culture parameters and solubilising agents were used but they did not produce bioactive His-GK; however, co-expression of His-GK with molecular chaperones, specifically pKJE7, achieved expression of bioactive His-GK. The overexpressed bioactive His-GK was purified using coloumn chromatography and characterised using enzyme kinetics. RESULTS The overexpressed bioactive His-GK was purified apparently to homogeneity (∼295-fold) and characterised. The native His-GK was a dimer with a monomeric molecular weight of ∼55 kDa. Optimal enzyme activity was observed in TEA buffer (50 mM) at 7.5 pH. K+ (40 mM) and Mg2+ (2.0 mM) emerged as prefered metal ions for His-GK activity with specific activity 0.780 U/mg protein. The purified His-GK obeyed standard Michaelis-Menten kinetics with Km value of 5.022 µM (R2=0.927) for its substrate glycerol; whereas, that for ATP and PEP was 0.767 mM (R2=0.928) and 0.223 mM (R2=0.967), respectively. Other optimal parameters for the substrate and co-factors were also determined. CONCLUSION The present study demonstrates that co-expression of molecular chaperones assists with the expression of bioactive human GK for its characterisation.
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Affiliation(s)
- Riva Mary Rani
- Biological Chemistry Laboratory, Department of Zoology, North-Eastern Hill University, Shillong 793022, India
| | - Superior Syngkli
- Biological Chemistry Laboratory, Department of Zoology, North-Eastern Hill University, Shillong 793022, India
| | - Joplin Nongkhlaw
- Biological Chemistry Laboratory, Department of Zoology, North-Eastern Hill University, Shillong 793022, India
| | - Bidyadhar Das
- Biological Chemistry Laboratory, Department of Zoology, North-Eastern Hill University, Shillong 793022, India
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2
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Blasco Tavares Pereira Lopes F, Schlatzer D, Wang R, Li X, Feng E, Koyutürk M, Qi X, Chance MR. Temporal and Sex-Linked Protein Expression Dynamics in a Familial Model of Alzheimer's Disease. Mol Cell Proteomics 2022; 21:100280. [PMID: 35944844 PMCID: PMC9483563 DOI: 10.1016/j.mcpro.2022.100280] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 07/27/2022] [Accepted: 08/03/2022] [Indexed: 12/03/2022] Open
Abstract
Mouse models of Alzheimer's disease (AD) show progression through stages reflective of human pathology. Proteomics identification of temporal and sex-linked factors driving AD-related pathways can be used to dissect initiating and propagating events of AD stages to develop biomarkers or design interventions. In the present study, we conducted label-free proteome measurements of mouse hippocampus tissue with variables of time (3, 6, and 9 months), genetic background (5XFAD versus WT), and sex (equal males and females). These time points are associated with well-defined phenotypes with respect to the following: Aβ42 plaque deposition, memory deficits, and neuronal loss, allowing correlation of proteome-based molecular signatures with the mouse model stages. Our data show 5XFAD mice exhibit increases in known human AD biomarkers as amyloid-beta peptide, APOE, GFAP, and ITM2B are upregulated across all time points/stages. At the same time, 23 proteins are here newly associated with Alzheimer's pathology as they are also dysregulated in 5XFAD mice. At a pathways level, the 5XFAD-specific upregulated proteins are significantly enriched for DNA damage and stress-induced senescence at 3-month only, while at 6-month, the AD-specific proteome signature is altered and significantly enriched for membrane trafficking and vesicle-mediated transport protein annotations. By 9-month, AD-specific dysregulation is also characterized by significant neuroinflammation with innate immune system, platelet activation, and hyper-reactive astrocyte-related enrichments. Aside from these temporal changes, analysis of sex-linked differences in proteome signatures uncovered novel sex and AD-associated proteins. Pathway analysis revealed sex-linked differences in the 5XFAD model to be involved in the regulation of well-known human AD-related processes of amyloid fibril formation, wound healing, lysosome biogenesis, and DNA damage. Verification of the discovery results by Western blot and parallel reaction monitoring confirm the fundamental conclusions of the study and poise the 5XFAD model for further use as a molecular tool for understanding AD.
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Affiliation(s)
- Filipa Blasco Tavares Pereira Lopes
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Center for Proteomics and Bioinformatics, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Daniela Schlatzer
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Center for Proteomics and Bioinformatics, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Rihua Wang
- Department of Physiology & Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Center for Mitochondrial Diseases, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Xiaolin Li
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Center for Proteomics and Bioinformatics, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Emily Feng
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Center for Proteomics and Bioinformatics, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Mehmet Koyutürk
- Center for Proteomics and Bioinformatics, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Department of Computer and Data Sciences, Case School of Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Xin Qi
- Department of Physiology & Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Center for Mitochondrial Diseases, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Mark R Chance
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Center for Proteomics and Bioinformatics, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.
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3
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Keegan NP, Wilton SD, Fletcher S. Analysis of Pathogenic Pseudoexons Reveals Novel Mechanisms Driving Cryptic Splicing. Front Genet 2022; 12:806946. [PMID: 35140743 PMCID: PMC8819188 DOI: 10.3389/fgene.2021.806946] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/09/2021] [Indexed: 12/16/2022] Open
Abstract
Understanding pre-mRNA splicing is crucial to accurately diagnosing and treating genetic diseases. However, mutations that alter splicing can exert highly diverse effects. Of all the known types of splicing mutations, perhaps the rarest and most difficult to predict are those that activate pseudoexons, sometimes also called cryptic exons. Unlike other splicing mutations that either destroy or redirect existing splice events, pseudoexon mutations appear to create entirely new exons within introns. Since exon definition in vertebrates requires coordinated arrangements of numerous RNA motifs, one might expect that pseudoexons would only arise when rearrangements of intronic DNA create novel exons by chance. Surprisingly, although such mutations do occur, a far more common cause of pseudoexons is deep-intronic single nucleotide variants, raising the question of why these latent exon-like tracts near the mutation sites have not already been purged from the genome by the evolutionary advantage of more efficient splicing. Possible answers may lie in deep intronic splicing processes such as recursive splicing or poison exon splicing. Because these processes utilize intronic motifs that benignly engage with the spliceosome, the regions involved may be more susceptible to exonization than other intronic regions would be. We speculated that a comprehensive study of reported pseudoexons might detect alignments with known deep intronic splice sites and could also permit the characterisation of novel pseudoexon categories. In this report, we present and analyse a catalogue of over 400 published pseudoexon splice events. In addition to confirming prior observations of the most common pseudoexon mutation types, the size of this catalogue also enabled us to suggest new categories for some of the rarer types of pseudoexon mutation. By comparing our catalogue against published datasets of non-canonical splice events, we also found that 15.7% of pseudoexons exhibit some splicing activity at one or both of their splice sites in non-mutant cells. Importantly, this included seven examples of experimentally confirmed recursive splice sites, confirming for the first time a long-suspected link between these two splicing phenomena. These findings have the potential to improve the fidelity of genetic diagnostics and reveal new targets for splice-modulating therapies.
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Affiliation(s)
- Niall P. Keegan
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
- *Correspondence: Niall P. Keegan,
| | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
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4
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Miao L, Yang Y, Liu Y, Lai L, Wang L, Zhan Y, Yin R, Yu M, Li C, Yang X, Ge C. Glycerol kinase interacts with nuclear receptor NR4A1 and regulates glucose metabolism in the liver. FASEB J 2019; 33:6736-6747. [PMID: 30821173 DOI: 10.1096/fj.201800945rr] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Glycerol kinase (Gyk), consisting of 4 isoforms, plays a critical role in metabolism by converting glycerol to glycerol 3-phosphate in an ATP-dependent reaction. Only Gyk isoform b is present in whole cells, but its function in the nucleus remains elusive. Previous studies have shown that nuclear orphan receptor subfamily 4 group A member (NR4A)-1 is an important regulator of hepatic glucose homeostasis and lipid metabolism in adipose tissue. We aimed to elucidate the functional interaction between nuclear Gyk and NR4A1 during hepatic gluconeogenesis in the unfed state and diabetes. We identified nuclear Gyk as a novel corepressor of NR4A1 in the liver; moreover, this recruitment was dependent on the C-terminal ligand-binding domain instead of the N-terminal activation function 1 domain, which interacts with other NR4A1 coregulators. NR4A1 transcriptional activity was inhibited by Gyk via protein-protein interaction but not enzymatic activity. Moreover, Gyk overexpression suppressed NR4A1 ability to regulate the expression of target genes involved in hepatic gluconeogenesis in vitro and in vivo as well as blood glucose regulation, which was observed in both unfed and diabetic mice. These results highlight the moonlighting function of nuclear Gyk, which was found to act as a coregulator of NR4A1, participating in the regulation of hepatic glucose homeostasis in the unfed state and diabetes.-Miao, L., Yang, Y., Liu, Y., Lai, L., Wang, L., Zhan, Y., Yin, R., Yu, M., Li, C., Yang, X., Ge, C. Glycerol kinase interacts with nuclear receptor NR4A1 and regulates glucose metabolism in the liver.
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Affiliation(s)
- Lili Miao
- Beijing Institute of Radiation Medicine, Beijing, China.,Graduate School, Anhui Medical University, Hefei, China
| | - Yongsheng Yang
- Institute of AcuMoxibustion, China Academy of Chinese Medical Sciences, Beijing, China.,State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, China; and
| | - Yue Liu
- Beijing Institute of Radiation Medicine, Beijing, China.,Department of Pharmaceutical Engineering, Tianjin University, Tianjin, China
| | - Lili Lai
- Beijing Institute of Radiation Medicine, Beijing, China.,Graduate School, Anhui Medical University, Hefei, China
| | - Lei Wang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, China; and.,Department of Pharmaceutical Engineering, Tianjin University, Tianjin, China
| | - Yiqun Zhan
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, China; and
| | - Ronghua Yin
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, China; and
| | - Miao Yu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, China; and
| | - Changyan Li
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, China; and
| | - Xiaoming Yang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, China; and
| | - Changhui Ge
- Beijing Institute of Radiation Medicine, Beijing, China.,Graduate School, Anhui Medical University, Hefei, China
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5
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Parr LS, Sriram G, Nazarian R, Rahib L, Dipple KM. The ATP-stimulated translocation promoter (ASTP) activity of glycerol kinase plays central role in adipogenesis. Mol Genet Metab 2018; 124:254-265. [PMID: 29960856 DOI: 10.1016/j.ymgme.2018.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 06/05/2018] [Accepted: 06/05/2018] [Indexed: 11/16/2022]
Abstract
Glycerol kinase (GK) is a multifunctional enzyme located at the interface of carbohydrate and fat metabolism. It contributes to both central carbon metabolism and adipogenesis; specifically, through its role as the ATP-stimulated translocation promoter (ASTP). GK overexpression leads to increased ASTP activity and increased fat storage in H4IIE cells. We performed metabolic flux analysis in human GK-overexpressing H4IIE cells and found that overexpressing cells had significantly altered fluxes through central carbon and lipid metabolism including increased flux through the pentose phosphate pathway and increased production of lipids. We also observed an equal contribution of glycerol to carbohydrate metabolism in all cell lines, suggesting that GK's alternate functions rather than its enzymatic function are important for these processes. To further elucidate the contributions of the enzymatic (phosphorylation) and alternative (ASTP) functions of GK in adipogenesis, we performed experiments on mammalian GK and E. coli GK. We determined that the ASTP function of GK (which is absent in E. coli GK) plays a greater role than the enzymatic activity in these processes. These studies further emphasize GK's diverse functionality and provides fundamental insights into the multiple protein functions of glycerol kinase.
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Affiliation(s)
- Lilly S Parr
- Department of Human Genetics, David Geffen School of Medicine at UCLA, 695 Charles E. Young Drive South, Los Angeles, CA 90095-7088, USA
| | - Ganesh Sriram
- Department of Human Genetics, David Geffen School of Medicine at UCLA, 695 Charles E. Young Drive South, Los Angeles, CA 90095-7088, USA; Department of Chemical and Biomolecular Engineering, Henry Samueli School of Engineering and Applied Science at UCLA, 420 Westwood Plaza, Los Angeles, CA 90095, USA; Department of Chemical and Biomolecular Engineering, 1208D Building 90, Chemical and Nuclear Engineering Bldg, University of Maryland, College Park, MD 20742-2111, USA
| | - Ramin Nazarian
- Department of Medicine/Dermatology, David Geffen School of Medicine at UCLA, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA
| | - Lola Rahib
- Biomedical Engineering, Interdepartmental Program, Henry Samueli School of Engineering and Applied Science at UCLA, 420 Westwood Plaza, Los Angeles, CA 90095, USA
| | - Katrina M Dipple
- Department of Human Genetics, David Geffen School of Medicine at UCLA, 695 Charles E. Young Drive South, Los Angeles, CA 90095-7088, USA; Biomedical Engineering, Interdepartmental Program, Henry Samueli School of Engineering and Applied Science at UCLA, 420 Westwood Plaza, Los Angeles, CA 90095, USA; Department of Pediatrics, David Geffen School of Medicine at UCLA, Mattel Children's Hospital at UCLA, 10833 Le Conte Avenue, Los Angeles, CA 90095-1782, USA; University of Washington, Department of Pediatrics, Seattle Children's Hospital, Division of Genetic Medicine, 4800 Sand Point Way NE, Seattle, WA 98105, USA.
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6
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Zhang YH, Van Hove JL, McCabe ER, Dipple KM. Gestational Diabetes Associated with a Novel Mutation (378-379insTT) in the Glycerol Kinase Gene. Mol Genet Metab Rep 2015; 4:42-45. [PMID: 26309814 PMCID: PMC4545508 DOI: 10.1016/j.ymgmr.2015.06.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Glycerol kinase deficiency (GKD) is an X-linked inborn error of metabolism at the interface of fat and carbohydrate metabolism. We report a male patient with GKD and a novel insertion of TT in exon 5 at position 378 of the GK cDNA (378–379insTT). This resulted in a premature stop codon and 0.8% normal GK activity. The mother is a carrier for this mutation and had gestational diabetes requiring insulin during this pregnancy but not in her previous pregnancy. Given the association between GKD and type 2 diabetes mellitus, it is interesting that the mother had gestational diabetes while carrying an affected fetus. Therefore, GKD is another disease where there may be a maternal–fetal interaction based on genotype. Further investigations may help elucidate the role of GKD in the carrier mother's gestational diabetes. In addition, these studies will provide better-informed counseling to families with GKD regarding the risk to carrier females.
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Affiliation(s)
- Yao H. Zhang
- Department of Pediatrics, David Geffen School of Medicine at UCLA, and Mattel Children's Hospital UCLA, Los Angeles, CA 90095-1752, USA
| | - Johan L. Van Hove
- Department of Pediatrics, Catholic University Leuven, Leuven B3000, Belgium
| | - Edward R.B. McCabe
- Department of Pediatrics, David Geffen School of Medicine at UCLA, and Mattel Children's Hospital UCLA, Los Angeles, CA 90095-1752, USA
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-7088, USA
- Interdepartmental Program, Biomedical Engineering, Henry Samulei School of Engineering and Applied Sciences at UCLA, Los Angeles, CA 90095, USA
| | - Katrina M. Dipple
- Department of Pediatrics, David Geffen School of Medicine at UCLA, and Mattel Children's Hospital UCLA, Los Angeles, CA 90095-1752, USA
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-7088, USA
- Interdepartmental Program, Biomedical Engineering, Henry Samulei School of Engineering and Applied Sciences at UCLA, Los Angeles, CA 90095, USA
- Corresponding author at: Departments of Human Genetics and Pediatrics, David Geffen School of Medicine at UCLA, Gonda Center 5506B, 695 Charles E. Young Drive South, Los Angeles, CA 90095-7088, USA.
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7
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Wightman PJ, Jackson GR, Dipple KM. Disruption of glycerol metabolism by RNAi targeting of genes encoding glycerol kinase results in a range of phenotype severity in Drosophila. PLoS One 2013; 8:e71664. [PMID: 24039719 PMCID: PMC3765373 DOI: 10.1371/journal.pone.0071664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 07/02/2013] [Indexed: 12/03/2022] Open
Abstract
In Drosophila, RNAi targeting of either dGyk or dGK can result in two alternative phenotypes: adult glycerol hypersensitivity or larval lethality. Here we compare these two phenotypes at the level of glycerol kinase (GK) phosphorylation activity, dGyk and dGK-RNA expression, and glycerol levels. We found both phenotypes exhibit reduced but similar levels of GK phosphorylation activity. Reduced RNA expression levels of dGyk and dGK corresponded with RNAi progeny that developed into glycerol hypersensitive adult flies. However, quantification of dGyk/dGK expression levels for the larval lethality phenotype revealed unexpected levels possibly due to a compensatory mechanism between dGyk and dGK or RNAi inhibition. The enzymatic role of glycerol kinase converts glycerol to glycerol 3-phosphate. As expected, elevated glycerol levels were observed in larvae that went on to develop into glycerol hypersensitive adults. Interestingly, larvae that died before eclosion revealed extremely low glycerol levels. Further characterization identified a wing phenotype that is enhanced by a dGpdh null mutation, indicating disrupted glycerol metabolism underlies the wing phenotype. In humans, glycerol kinase deficiency (GKD) exhibits a wide range of phenotypic variation with no obvious genotype-phenotype correlations. Additionally, disease severity often does not correlate with GK phosphorylation activity. It is intriguing that both human GKD patients and our GKD Drosophila model show a range of phenotype severity. Additionally, the lack of correlation between GK phosphorylation and dGyk/dGK-RNA expression with phenotypic severity suggests further study including understanding the alternative functions of the GK protein, could provide insights into the complex pathogenic mechanism observed in human GKD patients.
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Affiliation(s)
- Patrick J. Wightman
- Department of Human Genetics, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
| | - George R. Jackson
- Department of Neurology, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
- Brain Research Institute, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
| | - Katrina M. Dipple
- Department of Human Genetics, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
- Department of Pediatrics, David Geffen School of Medicine at University of California Los Angeles, Mattel Children's Hospital at University of California, Los Angeles, Los Angeles California, United States of America
- * E-mail:
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8
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García García E, Martínez Ortega AJ, Fernández García R, Madruga Garrido M. [Congenital adrenal hypoplasia as the first manifestation of a contiguous deletion of genes in Xp21]. Med Clin (Barc) 2013. [PMID: 23177307 DOI: 10.1016/j.medcli.2012.09.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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Glycerol hypersensitivity in a Drosophila model for glycerol kinase deficiency is affected by mutations in eye pigmentation genes. PLoS One 2012; 7:e31779. [PMID: 22427807 PMCID: PMC3302884 DOI: 10.1371/journal.pone.0031779] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 01/18/2012] [Indexed: 01/10/2023] Open
Abstract
Glycerol kinase plays a critical role in metabolism by converting glycerol to glycerol 3-phosphate in an ATP dependent reaction. In humans, glycerol kinase deficiency results in a wide range of phenotypic variability; patients can have severe metabolic and CNS abnormalities, while others possess hyperglycerolemia and glyceroluria with no other apparent phenotype. In an effort to help understand the pathogenic mechanisms underlying the phenotypic variation, we have created a Drosophila model for glycerol kinase deficiency by RNAi targeting of dGyk (CG18374) and dGK (CG7995). As expected, RNAi flies have reduced glycerol kinase RNA expression, reduced phosphorylation activity and elevated glycerol levels. Further investigation revealed these flies to be hypersensitive to fly food supplemented with glycerol. Due to the hygroscopic nature of glycerol, we predict glycerol hypersensitivity is a result of greater susceptibility to desiccation, suggesting glycerol kinase to play an important role in desiccation resistance in insects. To evaluate a role for genetic modifier loci in determining severity of the glycerol hypersensitivity observed in knockdown flies, we performed a preliminary screen of lethal transposon insertion mutant flies using a glycerol hypersensitive survivorship assay. We demonstrate that this type of screen can identify both enhancer and suppressor genetic loci of glycerol hypersensitivity. Furthermore, we found that the glycerol hypersensitivity phenotype can be enhanced or suppressed by null mutations in eye pigmentation genes. Taken together, our data suggest proteins encoded by eye pigmentation genes play an important role in desiccation resistance and that eye pigmentation genes are strong modifiers of the glycerol hypersensitive phenotype identified in our Drosophila model for glycerol kinase deficiency.
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10
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Theisen A, Shaffer LG. Disorders caused by chromosome abnormalities. APPLICATION OF CLINICAL GENETICS 2010; 3:159-74. [PMID: 23776360 PMCID: PMC3681172 DOI: 10.2147/tacg.s8884] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Many human genetic disorders result from unbalanced chromosome abnormalities, in which there is a net gain or loss of genetic material. Such imbalances often disrupt large numbers of dosage-sensitive, developmentally important genes and result in specific and complex phenotypes. Alternately, some chromosomal syndromes may be caused by a deletion or duplication of a single gene with pleiotropic effects. Traditionally, chromosome abnormalities were identified by visual inspection of the chromosomes under a microscope. The use of molecular cytogenetic technologies, such as fluorescence in situ hybridization and microarrays, has allowed for the identification of cryptic or submicroscopic imbalances, which are not visible under the light microscope. Microarrays have allowed for the identification of numerous new syndromes through a genotype-first approach in which patients with the same or overlapping genomic alterations are identified and then the phenotypes are described. Because many chromosomal alterations are large and encompass numerous genes, the ascertainment of individuals with overlapping deletions and varying clinical features may allow researchers to narrow the region in which to search for candidate genes.
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Kashork CD, Theisen A, Shaffer LG. Diagnosis of cryptic chromosomal syndromes by fluorescence in situ hybridization (FISH). CURRENT PROTOCOLS IN HUMAN GENETICS 2010; Chapter 8:Unit 8.10.1-20. [PMID: 20891031 DOI: 10.1002/0471142905.hg0810s67] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
This unit describes the various methods by which cytogeneticists detect chromosome abnormalities. The unit offers guidance for detecting such abnormalities with fluorescence in situ hybridization (FISH), as well as the benefits, limitations, and other applications of FISH.
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Sriram G, Parr LS, Rahib L, Liao JC, Dipple KM. Moonlighting function of glycerol kinase causes systems-level changes in rat hepatoma cells. Metab Eng 2010; 12:332-40. [PMID: 20399282 DOI: 10.1016/j.ymben.2010.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 04/08/2010] [Accepted: 04/12/2010] [Indexed: 10/19/2022]
Abstract
Glycerol kinase (GK) is an enzyme with diverse (moonlighting) cellular functions. GK overexpression affects central metabolic fluxes substantially; therefore, to elucidate the mechanism underlying these changes, we employed a systems-level evaluation of GK overexpression in H4IIE rat hepatoma cells. Microarray analysis revealed altered expression of genes in metabolism (central carbon and lipid), which correlated with previous flux analysis, and of genes regulated by the glucocorticoid receptor (GR). Oil Red O staining showed that GK overexpression leads to increased fat storage in H4IIE cells. Network component analysis revealed that activities of peroxisome proliferator-activated receptor alpha, GR, and seven other transcription factors were altered by GK overexpression. The increased activity of GR was experimentally verified by quantitative RT-PCR of GR-responsive genes in the presence and absence of the glucocorticoid agonist, dexamethasone. This systems biology approach further emphasizes GK's essential role in central and lipid metabolism and experimentally verifies GK's alternative (moonlighting) function of affecting GR transcription factor activity.
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Affiliation(s)
- Ganesh Sriram
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-7088, USA
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13
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Fabiani Romero F, Bermúdez de la Vega J, González Martin C, Gentil González J, Oribe A, Cruz C. Hiperglicerolemia, una seudohipertrigliceridemia: A propósito de un niño de 6 años de edad. An Pediatr (Barc) 2009; 71:68-71. [DOI: 10.1016/j.anpedi.2009.02.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 02/24/2009] [Accepted: 02/26/2009] [Indexed: 10/20/2022] Open
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Rahib L, Sriram G, Harada MK, Liao JC, Dipple KM. Transcriptomic and network component analysis of glycerol kinase in skeletal muscle using a mouse model of glycerol kinase deficiency. Mol Genet Metab 2009; 96:106-12. [PMID: 19121967 PMCID: PMC2702540 DOI: 10.1016/j.ymgme.2008.11.163] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Revised: 11/16/2008] [Accepted: 11/16/2008] [Indexed: 11/25/2022]
Abstract
Glycerol kinase (GK) is at the interface of fat and carbohydrate metabolism and has been linked to obesity and type 2 diabetes mellitus (T2DM). The purpose of this study was to investigate the role of GK in fat metabolism and insulin signaling in skeletal muscle (an important end organ tissue in T2DM). Microarray analysis determined that there were 525 genes that were differentially expressed (1.2-fold, p value<0.05) between knockout (KO) and wild-type (WT) mice. Quantitative PCR (qPCR) confirmed the differential expression of genes including glycerol kinase (Gyk), phosphatidylinositol 3-kinase regulatory subunit, polypeptide 1 (p85 alpha) (Pik3r1), insulin-like growth factor 1 (Igf1), and growth factor receptor bound protein 2-associated protein 1 (Gab1). Network component analysis demonstrated that transcription factor activities of myogenic differentiation 1 (MYOD), myogenic regulatory factor 5 (MYF5), myogenin (MYOG), nuclear receptor subfamily 4, group A, member 1 (NUR77) are decreased in the Gyk KO whereas the activity of paired box 3 (PAX3) is increased. The activity of MYOD was confirmed using a DNA binding assay. In addition, myoblasts from Gyk KO had less ability to differentiate into myotubes compared to WT myoblasts. These findings support our previous studies in brown adipose tissue and demonstrate that the role of Gyk in muscle is due in part to its non-metabolic (moonlighting) activities.
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MESH Headings
- Animals
- Cell Differentiation
- Cells, Cultured
- Diabetes Mellitus, Type 2/enzymology
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/metabolism
- Disease Models, Animal
- Female
- Gene Expression Profiling
- Gene Regulatory Networks
- Glycerol Kinase/deficiency
- Glycerol Kinase/genetics
- Humans
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle Fibers, Skeletal/cytology
- Muscle Fibers, Skeletal/enzymology
- Muscle Fibers, Skeletal/metabolism
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/metabolism
- Protein Binding
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Affiliation(s)
- Lola Rahib
- Biomedical Engineering Interdepartmental Program, Henry Samueli School of Engineering and Applied Science, University of California, Los Angeles, CA, USA
| | - Ganesh Sriram
- Department of Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA, USA
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA, USA
| | - Melissa K. Harada
- Department of Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA, USA
| | - James C. Liao
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA, USA
| | - Katrina M. Dipple
- Biomedical Engineering Interdepartmental Program, Henry Samueli School of Engineering and Applied Science, University of California, Los Angeles, CA, USA
- Department of Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA, USA
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Mattel Children’s Hospital at UCLA, University of California, Los Angeles, CA, USA
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15
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Shaikh MG, Boyes L, Kingston H, Collins R, Besley GTN, Padmakumar B, Ismayl O, Hughes I, Hall CM, Hellerud C, Achermann JC, Clayton PE. Skewed X inactivation is associated with phenotype in a female with adrenal hypoplasia congenita. J Med Genet 2008; 45:e1. [PMID: 18762570 PMCID: PMC2602739 DOI: 10.1136/jmg.2007.055129] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Adrenal hypoplasia congenita (AHC) can occur due to deletions or mutations in the DAX 1 (NR0B1) gene on the X chromosome (OMIM 300200). This form of AHC is therefore predominantly seen in boys. Deletion of the DAX 1 gene can also be part of a larger contiguous deletion including the centromeric dystrophin and glycerol kinase (GK) genes. We report a girl with a de novo deletion at Xp21.2 on the maternal chromosome, including DAX1, the GK gene and 3′ end of the dystrophin gene, who presented with salt losing adrenal insufficiency and moderate developmental delay, but relatively mild features of muscular dystrophy. Investigation using the androgen receptor as a marker gene identified skewed inactivation of the X chromosome. In the patient’s leucocytes, the paternal X chromosome was completely inactive, but in muscle 20% of the active chromosomes were of paternal origin. Thus skewed X inactivation (deletion on the active maternal X chromosome with an inactive paternal X chromosome) is associated with AHC in a female. Variability in X inactivation between tissues may account for the pronounced salt loss and adrenal insufficiency but mild muscular dystrophy.
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Affiliation(s)
- M G Shaikh
- Department of Endocrinology, Royal Manchester Children's Hospital, Manchester, M27 4HA, UK
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16
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Sriram G, Rahib L, He JS, Campos AE, Parr LS, Liao JC, Dipple KM. Global metabolic effects of glycerol kinase overexpression in rat hepatoma cells. Mol Genet Metab 2008; 93:145-59. [PMID: 18029214 PMCID: PMC2702542 DOI: 10.1016/j.ymgme.2007.09.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Accepted: 09/10/2007] [Indexed: 10/22/2022]
Abstract
Glycerol kinase has several diverse activities in mammalian cells. Glycerol kinase deficiency is a complex, single-gene, inborn error of metabolism wherein no genotype-phenotype correlation has been established. Since glycerol kinase has been suggested to exhibit additional activities than glycerol phosphorylation, expression level perturbation in this enzyme may affect cellular physiology globally. To investigate this possibility, we conducted metabolic investigations of wild-type and two glycerol kinase-overexpressing H4IIE rat hepatoma cell lines constructed in this study. The glycerol kinase-overexpressing cell lines exhibited a significantly higher consumption of carbon sources per cell, suggesting excess carbon expenditure. Furthermore, we quantified intracellular metabolic fluxes by employing stable isotope 13C labeling with a mathematically designed substrate mixture, gas chromatography-mass spectrometry, and comprehensive isotopomer balancing. This flux analysis revealed that the pentose phosphate pathway flux in the glycerol kinase-overexpressing cell lines was 2-fold higher than that in the wild-type, in addition to subtler flux changes in other pathways of carbohydrate metabolism. Furthermore, the activity and transcript level of the lipogenic enzyme glucose-6-phosphate dehydrogenase, the rate-limiting enzyme of the pentose phosphate pathway, were also about 2-fold higher than that of the wild-type; these data corroborate the flux analysis results. This study shows that glycerol kinase affects carbon metabolism globally, possibly through its additional functions, and highlights glycerol kinase's multifaceted role in cellular physiology.
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Affiliation(s)
- Ganesh Sriram
- Department of Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, California
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California
| | - Lola Rahib
- Biomedical Engineering Interdepartmental Program, Henry Samueli School of Engineering and Applied Science, University of California, Los Angeles, California
| | - Jian-Sen He
- Department of Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, California
| | - Allison E. Campos
- Department of Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, California
| | - Lilly S. Parr
- Department of Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, California
| | - James C. Liao
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California
- Biomedical Engineering Interdepartmental Program, Henry Samueli School of Engineering and Applied Science, University of California, Los Angeles, California
| | - Katrina M. Dipple
- Department of Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, California
- Biomedical Engineering Interdepartmental Program, Henry Samueli School of Engineering and Applied Science, University of California, Los Angeles, California
- Department of Pediatrics, David Geffen School of Medicine at UCLA, and Mattel Children’s Hospital at UCLA, University of California, Los Angeles, California
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17
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Illsinger S, Marquardt I, Lücke T, Hellerud C, Korenke C, Das AM. Two cases of isolated glycerol kinase deficiency with heterogeneous neurological symptoms. Dev Med Child Neurol 2007; 49:396-7. [PMID: 17489818 DOI: 10.1111/j.1469-8749.2007.00396.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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18
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Klein RD, Thorland EC, Gonzales PR, Beck PA, Dykas DJ, McGrath JM, Bale AE. A multiplex assay for the detection and mapping of complex glycerol kinase deficiency. Clin Chem 2006; 52:1864-70. [PMID: 16887896 DOI: 10.1373/clinchem.2006.072397] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Glycerol kinase deficiency (GKD) is an X-linked recessive disorder that presents in both isolated and complex forms. The contiguous deletion that leads to GKD also commonly affects NR0B1 (DAX1), the gene associated with adrenal hypoplasia congenita, and DMD, the Duchenne muscular dystrophy gene. Molecular testing to delineate this deletion is expensive and has only limited availability. METHODS We designed a multiplex PCR assay for the detection and mapping of a contiguous deletion potentially affecting the IL1RAPL1, NR0B1, GK, and DMD genes in a 29-month-old male patient with GKD. RESULTS Multiplex PCR detected a contiguous deletion that involved the IL1RAPL1, NR0B1, GK, and DMD genes. Although the patient had a creatine kinase concentration within the reference interval, further mapping with PCR revealed that exon 74 was the last intact exon at the 3' end of the DMD gene. CONCLUSIONS Multiplex PCR is an effective and inexpensive way to detect and map the contiguous deletion in cases of complex GKD. The extension of a deletion to include DMD exon 75 in a patient with a creatine kinase concentration within the reference interval suggests that this region of the gene may not be essential for protein function.
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Affiliation(s)
- Roger D Klein
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55901, USA.
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19
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Kuwada N, Nagano K, MacLennan N, Havens J, Kumar M, Dipple KM, McCabe ERB. Gene therapy for murine glycerol kinase deficiency: Importance of murine ortholog. Biochem Biophys Res Commun 2005; 335:247-55. [PMID: 16105550 DOI: 10.1016/j.bbrc.2005.07.066] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2005] [Accepted: 07/13/2005] [Indexed: 10/25/2022]
Abstract
A glycerol kinase (Gyk) knock-out (KO) mouse model permits improved understanding of glycerol kinase (GK) deficiency (GKD) pathogenesis, however, early death of affected mice limits its utility. The purpose of this work was to delay death of affected males to investigate thoroughly their phenotypes. An adenoviral vector carrying the human (Adeno-XGK) or mouse (Adeno-XGyk) GK gene was injected into KO mice within 24 h of birth. Adeno-XGK did not change KO mouse survival time despite liver GK activity greater than 100% of wild type. However, Adeno-XGyk improved KO mouse survival time greater than two-fold. These investigations demonstrate that gene replacement therapy for Gyk KO mice is more efficacious using murine Gyk than human GK. These studies expand our understanding of GKD pathogenesis in the murine model, and show that while murine GKD is more severe than in humans, GKD mice have similar metabolic disturbances to affected humans with hypoglycemia and acidemia.
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Affiliation(s)
- N Kuwada
- Department of Pediatrics, David Geffen School of Medicine at UCLA and Mattel Children's Hospital at UCLA, Los Angeles, CA 90095, USA
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20
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Ohira RH, Dipple KM, Zhang YH, McCabe ERB. Human and murine glycerol kinase: influence of exon 18 alternative splicing on function. Biochem Biophys Res Commun 2005; 331:239-46. [PMID: 15845384 DOI: 10.1016/j.bbrc.2005.03.143] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Indexed: 01/18/2023]
Abstract
Glycerol kinase (GK) is a key enzyme in glycerol metabolism with two alternatively spliced forms-one with an 87bp insertion corresponding to exon 18 (GK+EX18), and one lacking exon 18 (GK-EX18). We report the expression of GK+/-EX18 in various tissues and cell lines, as well as their enzymatic characteristics and subcellular localization. RT-PCR revealed differential expression in tissues and cell lines. Northern blot analysis revealed that both forms of the murine ortholog, Gyk, were highly expressed in murine heart and increased during embryonic development. K(m) values for glycerol for GK+/-EX18 were not significantly different, although GK-EX18 had a higher V(max) for glycerol. GK-EX18 had a lower K(m) and V(max) for ATP than GK+EX18. Immunofluorescence experiments showed that GK+EX18 co-localized to the mitochondria and the perinuclear region while GK-EX18 had a diffuse expression pattern. These data suggest specific and divergent roles for GK+EX18 and GK-EX18 in cellular metabolism and development.
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Affiliation(s)
- Riki H Ohira
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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21
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Sriram G, Martinez JA, McCabe ERB, Liao JC, Dipple KM. Single-gene disorders: what role could moonlighting enzymes play? Am J Hum Genet 2005; 76:911-24. [PMID: 15877277 PMCID: PMC1196451 DOI: 10.1086/430799] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2005] [Accepted: 04/05/2005] [Indexed: 11/03/2022] Open
Abstract
Single-gene disorders with "simple" Mendelian inheritance do not always imply that there will be an easy prediction of the phenotype from the genotype, which has been shown for a number of metabolic disorders. We propose that moonlighting enzymes (i.e., metabolic enzymes with additional functional activities) could contribute to the complexity of such disorders. The lack of knowledge about the additional functional activities of proteins could result in a lack of correlation between genotype and phenotype. In this review, we highlight some notable and recent examples of moonlighting enzymes and their possible contributions to human disease. Because knowledge and cataloging of the moonlighting activities of proteins are essential for the study of cellular function and human physiology, we also review recently reported and recommended methods for the discovery of moonlighting activities.
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Affiliation(s)
- Ganesh Sriram
- Department of Human Genetics and Division of Medical Genetics, Department of Pediatrics, David Geffen School of Medicine, Department of Chemical Engineering, Henry Samueli School of Engineering and Applied Science, and Mattel Children’s Hospital, University of California–Los Angeles, Los Angeles
| | - Julian A. Martinez
- Department of Human Genetics and Division of Medical Genetics, Department of Pediatrics, David Geffen School of Medicine, Department of Chemical Engineering, Henry Samueli School of Engineering and Applied Science, and Mattel Children’s Hospital, University of California–Los Angeles, Los Angeles
| | - Edward R. B. McCabe
- Department of Human Genetics and Division of Medical Genetics, Department of Pediatrics, David Geffen School of Medicine, Department of Chemical Engineering, Henry Samueli School of Engineering and Applied Science, and Mattel Children’s Hospital, University of California–Los Angeles, Los Angeles
| | - James C. Liao
- Department of Human Genetics and Division of Medical Genetics, Department of Pediatrics, David Geffen School of Medicine, Department of Chemical Engineering, Henry Samueli School of Engineering and Applied Science, and Mattel Children’s Hospital, University of California–Los Angeles, Los Angeles
| | - Katrina M. Dipple
- Department of Human Genetics and Division of Medical Genetics, Department of Pediatrics, David Geffen School of Medicine, Department of Chemical Engineering, Henry Samueli School of Engineering and Applied Science, and Mattel Children’s Hospital, University of California–Los Angeles, Los Angeles
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22
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Sjarif DR, Hellerud C, van Amstel JKP, Kleijer WJ, Sperl W, Lacombe D, Sass JO, Beemer FA, Duran M, Poll-The BT. Glycerol kinase deficiency: residual activity explained by reduced transcription and enzyme conformation. Eur J Hum Genet 2004; 12:424-32. [PMID: 15026783 DOI: 10.1038/sj.ejhg.5201172] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Four unrelated patients with glyceroluria ranging from 7 to 170 mmol/l were studied. The activity of glycerol kinase (GK) in cultured fibroblasts was determined with a specific enzyme assay and with two indirect methods, that is, incorporation into macromolecules of [(14)C] from [(14)C]glycerol and its oxidation to [(14)C]CO(2). Exon amplification and RT-PCR were used to identify mutations. In patient 1, with low activity in all three assays, we identified a c.1194A>C (E398D) missense mutation. In patient 2 with a considerable activity of the GK enzyme (22% of reference), oxidation to [(14)C]CO(2) (37%) and a high incorporation of [(14)C] into macromolecules (92%), we identified a c.182T>C (L61P) mutation that causes the enzyme to have a higher K(m) for glycerol ( approximately 300 microM) than normals (2-8 microM). In patient 3, the GK activity estimated by the three different methods ranged from 16 to 22% of reference. Analysis of mRNA from the GK gene revealed three alternatively spliced transcripts. A mutation in intron 3 (g.16835G>A) resulted in an insertion of a cryptic exon between exon 2 or 3 and exon 4. Patient 4 with minor glyceroluria (7 mmol/l) and normal plasma glycerol concentration had normal activity with all three assay methods, thus excluding GK deficiency (GKD) as a cause of slight glyceroluria. To evaluate fully patients with glyceroluria, one needs to measure the GK activity and relate this and the clinical data to genetic findings. Residual enzyme activities in cultured fibroblasts can be found in GKD patients with severe clinical symptoms.
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Affiliation(s)
- Damayanti R Sjarif
- Department of Medical Genetics, University Medical Center, Utrecht, The Netherlands
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23
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Hellerud C, Adamowicz M, Jurkiewicz D, Taybert J, Kubalska J, Ciara E, Popowska E, Ellis JR, Lindstedt S, Pronicka E. Clinical heterogeneity and molecular findings in five Polish patients with glycerol kinase deficiency: investigation of two splice site mutations with computerized splice junction analysis and Xp21 gene-specific mRNA analysis. Mol Genet Metab 2003; 79:149-59. [PMID: 12855219 DOI: 10.1016/s1096-7192(03)00094-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Five cases of glycerol kinase deficiency are presented with clinical, biochemical, and genetic results. Two had the glycerol kinase deficiency as part of an Xp21 contiguous gene deletion syndrome-complex form-and three had an isolated form of the enzyme deficiency. In these we found two splice site mutations (IVS1+4A>G, IVS9-1G>T) and one insertion (1393_1394insG). In patients with the complex form, a deletion of the DAX1, GK genes and the distal part of the DMD gene was found. A computerized study was performed to predict the effects of the splice site mutations. It showed that the IVS9-1G>T mutation substantially altered and removed the wild-type site and enhanced a cryptic site seven nucleotides downstream, and that the IVS1+4A>G diminished the strength of the wild-type donor site from strong to leaky. To verify these predictions, we developed an RT-PCR system with gene-specific primers that exclusively amplifies the Xp21 glycerol kinase gene transcript. Identification of individuals at risk is motivated by a need to avoid delay in a correct diagnosis. For reliable identification of heterozygotes for isolated glycerol kinase deficiency, knowledge of the specific mutation in the proband is required. This is easily obtained with the RT-PCR analyses developed in this study.
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MESH Headings
- Adrenal Insufficiency/genetics
- Chromosomes, Human, X
- DAX-1 Orphan Nuclear Receptor
- DNA Mutational Analysis
- DNA Primers/chemistry
- DNA-Binding Proteins/chemistry
- DNA-Binding Proteins/deficiency
- DNA-Binding Proteins/genetics
- Gene Deletion
- Glycerol/blood
- Glycerol/urine
- Glycerol Kinase/chemistry
- Glycerol Kinase/deficiency
- Glycerol Kinase/genetics
- Humans
- Infant, Newborn
- Male
- Molecular Sequence Data
- Muscular Dystrophy, Duchenne/genetics
- Mutation
- Poland
- Polymorphism, Single-Stranded Conformational
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Retinoic Acid/chemistry
- Receptors, Retinoic Acid/deficiency
- Receptors, Retinoic Acid/genetics
- Repressor Proteins/chemistry
- Repressor Proteins/genetics
- Reverse Transcriptase Polymerase Chain Reaction/methods
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Affiliation(s)
- Christina Hellerud
- Department of Clinical Chemistry and Transfusion Medicine, Sahlgrenska University Hospital, Göteborg University, Bruna Stråket 16, S 413 415 Gothenburg, Sweden.
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24
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Hellerud C, Burlina A, Gabelli C, Ellis JR, Nyholm PG, Lindstedt S. Glycerol metabolism and the determination of triglycerides--clinical, biochemical and molecular findings in six subjects. Clin Chem Lab Med 2003; 41:46-55. [PMID: 12636049 DOI: 10.1515/cclm.2003.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Recent recommendations in the National Cholesterol Education Program Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (ATPIII) are expected to increase the number of triglyceride (TG) determinations and consequently the risk of misinterpretation of "non-blanked" results with co-determination of free glycerol. Glycerol-kinase deficiency (GKD) is one cause of falsely elevated TG results. The natural history of isolated GKD with symptom-free cases and cases with e.g. severe episodes of hypoglycemia and/or ketoacidosis challenges the laboratories to identify cases of GKD and family members at risk. "Blanked" methods reporting both glycerol and TG concentration are therefore desirable. Molecular studies of the glycerol kinase (GK) and DAX1 genes were performed on four cases of "persistent hypertriglyceridemia" found in an Italian population and on two pediatric cases with high serum glycerol concentration. Two new missense mutations were found (C358Y, T961). Molecular modeling on GK from E. coli, indicate that these mutations are located in parts of the enzyme important for enzyme formation or activity. One splice-site mutation, (IVS9A-1G>A), was found in two brothers. Splice-junction analysis indicates that it destroys the splice site and results in a mixture of mRNA. Deletion of the GK and DAX1 genes was found in one child with symptoms of adrenal failure. A female with glycerolemia and glyceroluria had normal GK activity but possibly slightly decreased ability to oxidize glycerol.
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Affiliation(s)
- Christina Hellerud
- Department of Clinical Chemistry, Sahlgrenska University Hospital, Göteborg University, Gothenburg, Sweden.
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