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Abu Aqel Y, Alnesf A, Aigha II, Islam Z, Kolatkar PR, Teo A, Abdelalim EM. Glucokinase (GCK) in diabetes: from molecular mechanisms to disease pathogenesis. Cell Mol Biol Lett 2024; 29:120. [PMID: 39245718 PMCID: PMC11382428 DOI: 10.1186/s11658-024-00640-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Accepted: 08/23/2024] [Indexed: 09/10/2024] Open
Abstract
Glucokinase (GCK), a key enzyme in glucose metabolism, plays a central role in glucose sensing and insulin secretion in pancreatic β-cells, as well as glycogen synthesis in the liver. Mutations in the GCK gene have been associated with various monogenic diabetes (MD) disorders, including permanent neonatal diabetes mellitus (PNDM) and maturity-onset diabetes of the young (MODY), highlighting its importance in maintaining glucose homeostasis. Additionally, GCK gain-of-function mutations lead to a rare congenital form of hyperinsulinism known as hyperinsulinemic hypoglycemia (HH), characterized by increased enzymatic activity and increased glucose sensitivity in pancreatic β-cells. This review offers a comprehensive exploration of the critical role played by the GCK gene in diabetes development, shedding light on its expression patterns, regulatory mechanisms, and diverse forms of associated monogenic disorders. Structural and mechanistic insights into GCK's involvement in glucose metabolism are discussed, emphasizing its significance in insulin secretion and glycogen synthesis. Animal models have provided valuable insights into the physiological consequences of GCK mutations, although challenges remain in accurately recapitulating human disease phenotypes. In addition, the potential of human pluripotent stem cell (hPSC) technology in overcoming current model limitations is discussed, offering a promising avenue for studying GCK-related diseases at the molecular level. Ultimately, a deeper understanding of GCK's multifaceted role in glucose metabolism and its dysregulation in disease states holds implications for developing targeted therapeutic interventions for diabetes and related disorders.
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Affiliation(s)
- Yasmin Abu Aqel
- Laboratory of Pluripotent Stem Cell Disease Modeling, Translational Medicine Division, Research Branch, Sidra Medicine, P.O. Box 26999, Doha, Qatar
| | - Aldana Alnesf
- Laboratory of Pluripotent Stem Cell Disease Modeling, Translational Medicine Division, Research Branch, Sidra Medicine, P.O. Box 26999, Doha, Qatar
- College of Health and Life Sciences, Hamad Bin Khalifa University (HBKU), Qatar Foundation, Education City, Doha, Qatar
| | - Idil I Aigha
- Laboratory of Pluripotent Stem Cell Disease Modeling, Translational Medicine Division, Research Branch, Sidra Medicine, P.O. Box 26999, Doha, Qatar
| | - Zeyaul Islam
- Diabetes Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), PO Box 34110, Doha, Qatar
| | - Prasanna R Kolatkar
- College of Health and Life Sciences, Hamad Bin Khalifa University (HBKU), Qatar Foundation, Education City, Doha, Qatar
- Diabetes Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), PO Box 34110, Doha, Qatar
| | - Adrian Teo
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Proteos, Singapore, Singapore
- Department of Biochemistry and Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Precision Medicine Translational Research Programme (PM TRP), Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Essam M Abdelalim
- Laboratory of Pluripotent Stem Cell Disease Modeling, Translational Medicine Division, Research Branch, Sidra Medicine, P.O. Box 26999, Doha, Qatar.
- College of Health and Life Sciences, Hamad Bin Khalifa University (HBKU), Qatar Foundation, Education City, Doha, Qatar.
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Gersing S, Schulze TK, Cagiada M, Stein A, Roth FP, Lindorff-Larsen K, Hartmann-Petersen R. Characterizing glucokinase variant mechanisms using a multiplexed abundance assay. Genome Biol 2024; 25:98. [PMID: 38627865 PMCID: PMC11021015 DOI: 10.1186/s13059-024-03238-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 04/04/2024] [Indexed: 04/19/2024] Open
Abstract
BACKGROUND Amino acid substitutions can perturb protein activity in multiple ways. Understanding their mechanistic basis may pinpoint how residues contribute to protein function. Here, we characterize the mechanisms underlying variant effects in human glucokinase (GCK) variants, building on our previous comprehensive study on GCK variant activity. RESULTS Using a yeast growth-based assay, we score the abundance of 95% of GCK missense and nonsense variants. When combining the abundance scores with our previously determined activity scores, we find that 43% of hypoactive variants also decrease cellular protein abundance. The low-abundance variants are enriched in the large domain, while residues in the small domain are tolerant to mutations with respect to abundance. Instead, many variants in the small domain perturb GCK conformational dynamics which are essential for appropriate activity. CONCLUSIONS In this study, we identify residues important for GCK metabolic stability and conformational dynamics. These residues could be targeted to modulate GCK activity, and thereby affect glucose homeostasis.
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Affiliation(s)
- Sarah Gersing
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200, Copenhagen, Denmark.
| | - Thea K Schulze
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200, Copenhagen, Denmark
| | - Matteo Cagiada
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200, Copenhagen, Denmark
| | - Amelie Stein
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200, Copenhagen, Denmark
| | - Frederick P Roth
- Donnelly Centre, University of Toronto, M5S 3E1, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, M5S 1A8, Toronto, ON, Canada
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, M5G 1X5, Toronto, ON, Canada
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, 15213, Pittsburgh, USA
| | - Kresten Lindorff-Larsen
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200, Copenhagen, Denmark.
| | - Rasmus Hartmann-Petersen
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200, Copenhagen, Denmark.
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Gersing S, Schulze TK, Cagiada M, Stein A, Roth FP, Lindorff-Larsen K, Hartmann-Petersen R. Characterizing glucokinase variant mechanisms using a multiplexed abundance assay. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.24.542036. [PMID: 37292969 PMCID: PMC10245906 DOI: 10.1101/2023.05.24.542036] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Amino acid substitutions can perturb protein activity in multiple ways. Understanding their mechanistic basis may pinpoint how residues contribute to protein function. Here, we characterize the mechanisms of human glucokinase (GCK) variants, building on our previous comprehensive study on GCK variant activity. We assayed the abundance of 95% of GCK missense and nonsense variants, and found that 43% of hypoactive variants have a decreased cellular abundance. By combining our abundance scores with predictions of protein thermodynamic stability, we identify residues important for GCK metabolic stability and conformational dynamics. These residues could be targeted to modulate GCK activity, and thereby affect glucose homeostasis.
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Affiliation(s)
- Sarah Gersing
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark
| | - Thea K. Schulze
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark
| | - Matteo Cagiada
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark
| | - Amelie Stein
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark
| | - Frederick P. Roth
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, ON, M5G 1X5, Canada
- Department of Computer Science, University of Toronto, Toronto, ON, M5T 3A1, Canada
| | - Kresten Lindorff-Larsen
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark
| | - Rasmus Hartmann-Petersen
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark
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Dai T, Yang Y, Zhang J, Ma X, Chen L, Zhang C, Lv S, Li L, Tang R, Zhen N, Lu W, Li C, Hu R, Xiao Y, Dong Z. GCK exonic mutations induce abnormal biochemical activities and result in GCK-MODY. Front Genet 2023; 14:1120153. [PMID: 37082200 PMCID: PMC10110986 DOI: 10.3389/fgene.2023.1120153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 03/21/2023] [Indexed: 04/07/2023] Open
Abstract
Objective: Glucokinase-maturity-onset diabetes of the young (GCK-MODY; MODY2) is a rare genetic disorder caused by mutations in the glucokinase (GCK) gene. It is often under- or misdiagnosed in clinical practice, but correct diagnosis can be facilitated by genetic testing. In this study, we examined the genes of three patients diagnosed with GCK-MODY and tested their biochemical properties, such as protein stability and half-life, to explore the function of the mutant proteins and identify the pathogenic mechanism of GCK-MODY.Methods: Three patients with increased blood glucose levels were diagnosed with MODY2 according to the diagnostic guidelines of GCK-MODY proposed by the International Society for Pediatric and Adolescent Diabetes (ISPAD) in 2018. Next-generation sequencing (whole exome detection) was performed to detect gene mutations. The GCK gene and its mutations were introduced into the pCDNA3.0 and pGEX-4T-1 vectors. Following protein purification, enzyme activity assay, and protein immunoblotting, the enzyme activity of GCK was determined, along with the ubiquitination level of the mutant GCK protein.Results: Genetic testing revealed three mutations in the GCK gene of the three patients, including c.574C>T (p.R192W), c.758G>A (p.C253Y), and c.794G>A (p.G265D). The biochemical characteristics of the protein encoded by wild-type GCK and mutant GCK were different, compared to wild-type GCK, the enzyme activity encoded by the mutant GCK was reduced, suggesting thermal instability of the mutant GST-GCK. The protein stability and expression levels of the mutant GCK were reduced, and the enzyme activity of GCK was negatively correlated with the levels of fasting blood glucose and HbA1c. In addition, ubiquitination of the mutant GCK protein was higher than that of the wild-type, suggesting a higher degradation rate of mutant GCK than WT-GCK.Conclusion:GCK mutations lead to changes in the biochemical characteristics of its encoded proteins. The enzyme activities, protein expression, and protein stability of GCK may be reduced in patients with GCK gene mutations, which further causes glucose metabolism disorders and induces MODY2.
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Affiliation(s)
- Tongtong Dai
- Department of Pediatrics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yun Yang
- School of Medicine, Guizhou University, Guiyang, China
| | - Juanjuan Zhang
- Department of Pediatrics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaoyu Ma
- Department of Pediatrics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Lifen Chen
- Department of Pediatrics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Caiping Zhang
- Department of Pediatrics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Sheng Lv
- Department of Pediatrics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Lin Li
- Department of Pediatrics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Renqiao Tang
- Department of Pediatrics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ni Zhen
- Department of Pediatrics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Wenli Lu
- Department of Pediatrics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Chuanyin Li
- Cancer Center, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Ronggui Hu
- State Key Laboratory of Molecular Biology, Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Yuan Xiao
- Department of Pediatrics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Zhiya Dong
- Department of Pediatrics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
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Pace NP, Grech CA, Vella B, Caruana R, Vassallo J. Frequency and spectrum of glucokinase mutations in an adult Maltese population. Acta Diabetol 2022; 59:339-348. [PMID: 34677673 DOI: 10.1007/s00592-021-01814-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/06/2021] [Indexed: 12/19/2022]
Abstract
AIM To investigate the frequency and spectrum of glucokinase (GCK) mutations in a cohort of adults from an island population having a high prevalence of diabetes mellitus (DM). METHODS A single-centre cohort study was conducted, including 145 non-obese adults of Maltese-Caucasian ethnicity with impaired fasting glycaemia (IFG) or non-autoimmune diabetes diagnosed before the age of 40 years. Bidirectional sequencing of the GCK coding regions was performed. Genotype-phenotype associations and familial segregation were explored and the effects of missense variants on protein structure were evaluated using computational analysis. RESULTS Three probands with pathogenic/likely pathogenic GCK variants in the heterozygous state having clinical features consistent with GCK-diabetes were detected. The missense variants have structurally destabilising effects on protein structure. GCK variant carriers exhibited a significantly lower body mass index and serum triglyceride levels when compared to GCK variant non-carriers. CONCLUSIONS The frequency of GCK-diabetes is approximately 2% in non-obese Maltese adults with diabetes or prediabetes. This study broadens the mutational spectrum of GCK and highlights clinical features that could be useful in discriminating GCK-DM from type 2 DM or prediabetes. It reinforces the need for increased molecular testing in young adults with diabetes having a suspected monogenic aetiology.
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Affiliation(s)
- Nikolai Paul Pace
- Centre for Molecular Medicine and Biobanking, Faculty of Medicine and Surgery, University of Malta, Nikolai Paul Pace, Room 325, Msida, 2080, MSD, Malta.
| | - Celine Ann Grech
- Centre for Molecular Medicine and Biobanking, Faculty of Medicine and Surgery, University of Malta, Nikolai Paul Pace, Room 325, Msida, 2080, MSD, Malta
| | - Barbara Vella
- Centre for Molecular Medicine and Biobanking, Faculty of Medicine and Surgery, University of Malta, Nikolai Paul Pace, Room 325, Msida, 2080, MSD, Malta
| | - Ruth Caruana
- Department of Medicine, Faculty of Medicine and Surgery, University of Malta, Msida, MSD2080, Malta
| | - Josanne Vassallo
- Department of Medicine, Faculty of Medicine and Surgery, University of Malta, Msida, MSD2080, Malta
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César Ernesto LC, Álvaro EO, Yayoi SK, Juanita SS, María Teresa TL, Almeda-Valdes P. Differentiating Among Type 1, Type 2 Diabetes, and MODY: Raising Awareness About the Clinical Implementation of Genetic Testing in Latin America. AACE Clin Case Rep 2021; 7:138-140. [PMID: 34095472 PMCID: PMC8053617 DOI: 10.1016/j.aace.2020.11.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Objective To describe a case of maturity-onset diabetes of the young (MODY) to highlight the importance of a correct diabetes diagnosis. Methods We describe a Mexican family misdiagnosed with T1D and T2D. Results A 36-year-old woman with diabetes and adverse outcomes during 2 pregnancies had been diagnosed with T2D 10 years ago. Genetic testing was performed due to clinical and family history, which showed a pathogenic heterozygous variant c.544G>T (p.Val182Leu) in the GCK gene. This mutation was also confirmed in most of the family members who had been diagnosed with diabetes. Conclusion This case highlights the need for a correct diabetes classification. Reassessment of diabetes etiology is justified, especially in individuals with unclear clinical presentation or when family history is suggestive.
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Affiliation(s)
- Lam-Chung César Ernesto
- Department of Endocrinology and Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City, México
| | - Elizondo Ochoa Álvaro
- Department of Endocrinology and Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City, México
| | - Segura Kato Yayoi
- Molecular Biology and Genomic Medicine Unit; Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Silva-Serrano Juanita
- Department of Endocrinology and Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City, México
| | - Tusié Luna María Teresa
- Molecular Biology and Genomic Medicine Unit; Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Paloma Almeda-Valdes
- Department of Endocrinology and Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City, México
- Address correspondence and reprint requests to Dr. Paloma Almeda-Valdes, Department of Endocrinology and Metabolism,Vasco de Quiroga 15, Belisario Domínguez Sección XVI, Tlalpan 14080, México City, México.
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Wang Z, Diao C, Liu Y, Li M, Zheng J, Zhang Q, Yu M, Zhang H, Ping F, Li M, Xiao X. Identification and functional analysis of GCK gene mutations in 12 Chinese families with hyperglycemia. J Diabetes Investig 2019; 10:963-971. [PMID: 30592380 PMCID: PMC6626954 DOI: 10.1111/jdi.13001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 12/22/2018] [Accepted: 12/26/2018] [Indexed: 01/07/2023] Open
Abstract
AIMS/INTRODUCTION To investigate the clinical and genetic characteristics of Chinese patients with a phenotype consistent with maturity-onset diabetes of the young type 2 and explore the pathogenic mechanism of their hyperglycemia. MATERIALS AND METHODS We studied 12 probands and their extended families referred to our center for screening mutations in the glucokinase gene (GCK). Clinical data were collected and genetic analysis was carried out. The recombinant wild-type and mutant glucokinase were generated in Escherichia coli. The kinetic parameters and thermal stability of the enzymes were determined in vitro. RESULTS In the 12 families, 11 GCK mutations (R43C, T168A, K169N, R191W, Y215X, E221K, M235T, R250H, W257X, G261R and A379E) and one variant of uncertain significance (R275H) were identified. R191W was detected in two unrelated families. Of the 11 GCK mutations, three mutations (c.507G>C, K169N; c.645C>A, Y215X; c.771G>A, W257X; NM_000162.3, NP_000153.1) are novel. Basic kinetics analysis explained the pathogenicity of the five mutants (R43C, K169N, R191W, E221K and A379E), which showed reduced enzyme activity with relative activity indexes between ~0.001 and 0.5 compared with the wild-type (1.0). In addition, the thermal stabilities of these five mutants were also decreased to varying degrees. However, for R250H and R275H, there was no significant difference in the enzyme activity and thermal stability between the mutants and the wild type. CONCLUSIONS We have identified 11 GCK mutations and one variant of uncertain significance in 12 Chinese families with hyperglycemia. For five GCK mutations (R43C, K169N, R191W, E221K and A379E), the changes in enzyme kinetics and thermostability might be the pathogenic mechanisms by which mutations cause hyperglycemia.
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Affiliation(s)
- Zhixin Wang
- Key Laboratory of EndocrinologyTranslational Medicine CenterMinistry of HealthDepartment of EndocrinologyPeking Union Medical College HospitalDiabetes Research Center of Chinese Academy of Medical Sciences & Peking Union Medical CollegeBeijingChina
- Present address:
Department of EndocrinologyBeijing Jishuitan HospitalBeijingChina
| | - Chengming Diao
- Key Laboratory of EndocrinologyTranslational Medicine CenterMinistry of HealthDepartment of EndocrinologyPeking Union Medical College HospitalDiabetes Research Center of Chinese Academy of Medical Sciences & Peking Union Medical CollegeBeijingChina
| | - Yijing Liu
- Key Laboratory of EndocrinologyTranslational Medicine CenterMinistry of HealthDepartment of EndocrinologyPeking Union Medical College HospitalDiabetes Research Center of Chinese Academy of Medical Sciences & Peking Union Medical CollegeBeijingChina
| | - Mingmin Li
- Key Laboratory of EndocrinologyTranslational Medicine CenterMinistry of HealthDepartment of EndocrinologyPeking Union Medical College HospitalDiabetes Research Center of Chinese Academy of Medical Sciences & Peking Union Medical CollegeBeijingChina
| | - Jia Zheng
- Key Laboratory of EndocrinologyTranslational Medicine CenterMinistry of HealthDepartment of EndocrinologyPeking Union Medical College HospitalDiabetes Research Center of Chinese Academy of Medical Sciences & Peking Union Medical CollegeBeijingChina
| | - Qian Zhang
- Key Laboratory of EndocrinologyTranslational Medicine CenterMinistry of HealthDepartment of EndocrinologyPeking Union Medical College HospitalDiabetes Research Center of Chinese Academy of Medical Sciences & Peking Union Medical CollegeBeijingChina
| | - Miao Yu
- Key Laboratory of EndocrinologyTranslational Medicine CenterMinistry of HealthDepartment of EndocrinologyPeking Union Medical College HospitalDiabetes Research Center of Chinese Academy of Medical Sciences & Peking Union Medical CollegeBeijingChina
| | - Huabing Zhang
- Key Laboratory of EndocrinologyTranslational Medicine CenterMinistry of HealthDepartment of EndocrinologyPeking Union Medical College HospitalDiabetes Research Center of Chinese Academy of Medical Sciences & Peking Union Medical CollegeBeijingChina
| | - Fan Ping
- Key Laboratory of EndocrinologyTranslational Medicine CenterMinistry of HealthDepartment of EndocrinologyPeking Union Medical College HospitalDiabetes Research Center of Chinese Academy of Medical Sciences & Peking Union Medical CollegeBeijingChina
| | - Ming Li
- Key Laboratory of EndocrinologyTranslational Medicine CenterMinistry of HealthDepartment of EndocrinologyPeking Union Medical College HospitalDiabetes Research Center of Chinese Academy of Medical Sciences & Peking Union Medical CollegeBeijingChina
| | - Xinhua Xiao
- Key Laboratory of EndocrinologyTranslational Medicine CenterMinistry of HealthDepartment of EndocrinologyPeking Union Medical College HospitalDiabetes Research Center of Chinese Academy of Medical Sciences & Peking Union Medical CollegeBeijingChina
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Yellapu NK, Kandlapalli K, Kandimalla R, Adi PJ. Conformational transition pathway of R308K mutant glucokinase in the presence of the glucokinase activator YNKGKA4. FEBS Open Bio 2018; 8:1202-1208. [PMID: 30087826 PMCID: PMC6070654 DOI: 10.1002/2211-5463.12255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 05/30/2017] [Accepted: 06/02/2017] [Indexed: 11/18/2022] Open
Abstract
Glucokinase (GK) plays a vital role in the control of blood glucose levels and its altered activity can lead to the development of forms of diabetes. We have previously identified a mutant GK (R308K) in patients with type 2 diabetes with reduced enzyme activity. In the present study, the activation mechanism of GK from super‐open to the closed state under wild‐type and mutant conditions in the presence of the novel aminophosphonate derivative YNKGKA4 (an allosteric activator of GK) was characterized via a series of molecular dynamics simulations. A reliable conformational transition pathway of GK was observed from super‐open to closed state during trajectory analysis. Glucose was also observed to modulate its binding orientation in the active site but with stable moments in the cavity. These observations provide insights into the complicated conformational transitions in the presence of YNKGKA4 and the molecular mechanism of GK activators for the allosteric regulation of mutant forms of GK.
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Affiliation(s)
- Nanda Kumar Yellapu
- Biomedical Informatics Centre Vector Control Research Centre Indian Council of Medical Research Puducherry India
| | - Kalpana Kandlapalli
- Department of Biochemistry Sri Krishnadevaraya University Anantapuramu Andhrapradesh India
| | - Ramesh Kandimalla
- Garrison Institute on Aging Texas Tech University of Health Science Centre Lubbock TX USA
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Gutierrez-Nogués A, García-Herrero CM, Oriola J, Vincent O, Navas MA. Functional characterization of MODY2 mutations in the nuclear export signal of glucokinase. Biochim Biophys Acta Mol Basis Dis 2018; 1864:2385-2394. [PMID: 29704611 DOI: 10.1016/j.bbadis.2018.04.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/23/2018] [Accepted: 04/23/2018] [Indexed: 11/17/2022]
Abstract
Glucokinase (GCK) plays a key role in glucose homeostasis. Heterozygous inactivating mutations in the GCK gene cause the familial, mild fasting hyperglycaemia named MODY2. Besides its particular kinetic characteristics, glucokinase is regulated by subcellular compartmentation in hepatocytes. Glucokinase regulatory protein (GKRP) binds to GCK, leading to enzyme inhibition and import into the nucleus at fasting. When glucose concentration increases, GCK-GKRP dissociates and GCK is exported to the cytosol due to a nuclear export signal (NES). With the aim to characterize the GCK-NES, we have functionally analysed nine MODY2 mutations located within the NES sequence. Recombinant GCK mutants showed reduced catalytic activity and, in most cases, protein instability. Most of the mutants interact normally with GKRP, although mutations L306R and L309P impair GCK nuclear import in cotransfected cells. We demonstrated that GCK-NES function depends on exportin 1. We further showed that none of the mutations fully inactivate the NES, with the exception of mutation L304P, which likely destabilizes its α-helicoidal structure. Finally, we found that residue Glu300 negatively modulates the NES activity, whereas other residues have the opposite effect, thus suggesting that some of the NES spacer residues contribute to the low affinity of the NES for exportin 1, which is required for its proper functioning. In conclusion, our results have provided functional and structural insights regarding the GCK-NES and contributed to a better knowledge of the molecular mechanisms involved in the nucleo-cytoplasmic shuttling of glucokinase. Impairment of this regulatory mechanism by some MODY2 mutations might contribute to the hyperglycaemia in the patients.
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Affiliation(s)
- Angel Gutierrez-Nogués
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
| | - Carmen-María García-Herrero
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
| | - Josep Oriola
- Servicio de Bioquímica y Genética Molecular, Hospital Clínic, Departamento de Ciencias Fisiológicas I, Facultad de Medicina, Universidad de Barcelona, Barcelona, Spain
| | - Olivier Vincent
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain
| | - María-Angeles Navas
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas (CIBERDEM), www.ciberdem.net, Instituto de Salud Carlos III, Madrid, Spain; Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain.
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10
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Peng Y, Cooper SK, Li Y, Mei JM, Qiu S, Borchert GL, Donald SP, Kung HF, Phang JM. Ornithine-δ-Aminotransferase Inhibits Neurogenesis During Xenopus Embryonic Development. Invest Ophthalmol Vis Sci 2015; 56:2486-97. [PMID: 25783604 DOI: 10.1167/iovs.15-16509] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE In humans, deficiency of ornithine-δ-aminotransferase (OAT) results in progressive degeneration of the neural retina (gyrate atrophy) with blindness in the fourth decade. In this study, we used the Xenopus embryonic developmental model to study functions of the OAT gene on embryonic development. METHODS We cloned and sequenced full-length OAT cDNA from Xenopus oocytes (X-OAT) and determined X-OAT expression in various developmental stages of Xenopus embryos and in a variety of adult tissues. The phenotype, gene expression of neural developmental markers, and enzymatic activity were detected by gain-of-function and loss-of-function manipulations. RESULTS We showed that X-OAT is essential for Xenopus embryonic development, and overexpression of X-OAT produces a ventralized phenotype characterized by a small head, lack of axial structure, and defective expression of neural developmental markers. Using X-OAT mutants based on mutations identified in humans, we found that substitution of both Arg 180 and Leu 402 abrogated both X-OAT enzymatic activity and ability to modulate the developmental phenotype. Neurogenesis is inhibited by X-OAT during Xenopus embryonic development. CONCLUSIONS Neurogenesis is inhibited by X-OAT during Xenopus embryonic development, but it is essential for Xenopus embryonic development. The Arg 180 and Leu 402 are crucial for these effects of the OAT molecule in development.
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Affiliation(s)
- Ying Peng
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Sandra K Cooper
- Basic Research Program, Leidos, Inc., National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland, United States
| | - Yi Li
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jay M Mei
- Metabolism and Cancer Susceptibility Section, Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland, United States
| | - Shuwei Qiu
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Gregory L Borchert
- Basic Research Program, Leidos, Inc., National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland, United States
| | - Steven P Donald
- Metabolism and Cancer Susceptibility Section, Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland, United States
| | - Hsiang-Fu Kung
- State Key Laboratory of Oncology in Southern China, and Centre for Emerging Infectious Diseases, the Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - James M Phang
- Metabolism and Cancer Susceptibility Section, Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland, United States
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11
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Raimondo A, Chakera AJ, Thomsen SK, Colclough K, Barrett A, De Franco E, Chatelas A, Demirbilek H, Akcay T, Alawneh H, Flanagan SE, Van De Bunt M, Hattersley AT, Gloyn AL, Ellard S. Phenotypic severity of homozygous GCK mutations causing neonatal or childhood-onset diabetes is primarily mediated through effects on protein stability. Hum Mol Genet 2014; 23:6432-40. [PMID: 25015100 PMCID: PMC4240195 DOI: 10.1093/hmg/ddu360] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mutations in glucokinase (GCK) cause a spectrum of glycemic disorders. Heterozygous loss-of-function mutations cause mild fasting hyperglycemia irrespective of mutation severity due to compensation from the unaffected allele. Conversely, homozygous loss-of-function mutations cause permanent neonatal diabetes requiring lifelong insulin treatment. This study aimed to determine the relationship between in vitro mutation severity and clinical phenotype in a large international case series of patients with homozygous GCK mutations. Clinical characteristics for 30 patients with diabetes due to homozygous GCK mutations (19 unique mutations, including 16 missense) were compiled and assigned a clinical severity grade (CSG) based on birth weight and age at diagnosis. The majority (28 of 30) of subjects were diagnosed before 9 months, with the remaining two at 9 and 15 years. These are the first two cases of a homozygous GCK mutation diagnosed outside infancy. Recombinant mutant GCK proteins were analyzed for kinetic and thermostability characteristics and assigned a relative activity index (RAI) or relative stability index (RSI) value. Six of 16 missense mutations exhibited severe kinetic defects (RAI ≤ 0.01). There was no correlation between CSG and RAI (r(2) = 0.05, P = 0.39), indicating that kinetics alone did not explain the phenotype. Eighty percent of the remaining mutations showed reduced thermostability, the exceptions being the two later-onset mutations which exhibited increased thermostability. Comparison of CSG with RSI detected a highly significant correlation (r(2) = 0.74, P = 0.002). We report the largest case series of homozygous GCK mutations to date and demonstrate that they can cause childhood-onset diabetes, with protein instability being the major determinant of mutation severity.
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Affiliation(s)
- Anne Raimondo
- Oxford Centre for Diabetes Endocrinology & Metabolism, University of Oxford, Oxford OX3 7LE, UK
| | - Ali J Chakera
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK, Macleod Diabetes and Endocrine Centre and
| | - Soren K Thomsen
- Oxford Centre for Diabetes Endocrinology & Metabolism, University of Oxford, Oxford OX3 7LE, UK
| | - Kevin Colclough
- Molecular Genetics Laboratory, Royal Devon and Exeter NHS Foundation Trust, Exeter EX2 5DW, UK
| | - Amy Barrett
- Oxford Centre for Diabetes Endocrinology & Metabolism, University of Oxford, Oxford OX3 7LE, UK
| | - Elisa De Franco
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Alisson Chatelas
- Oxford Centre for Diabetes Endocrinology & Metabolism, University of Oxford, Oxford OX3 7LE, UK
| | - Huseyin Demirbilek
- Department of Paediatric Endocrinology, Diyarbakir Children State Hospital, Diyarbakir 21100, Turkey
| | - Teoman Akcay
- Division of Pediatric Endocrinology, Dr Sadi Konuk Education and Research Hospital, Bakirkoy, Istanbul 34147, Turkey
| | - Hussein Alawneh
- Pediatric Endocrine Division, Queen Rania Al Abdullah Hospital for Children, King Hussein Medical Center, Royal Medical Services, Amman 11814, Jordan and
| | | | - Sarah E Flanagan
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Martijn Van De Bunt
- Oxford Centre for Diabetes Endocrinology & Metabolism, University of Oxford, Oxford OX3 7LE, UK
| | - Andrew T Hattersley
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK, Macleod Diabetes and Endocrine Centre and
| | - Anna L Gloyn
- Oxford Centre for Diabetes Endocrinology & Metabolism, University of Oxford, Oxford OX3 7LE, UK, Oxford NIHR Biomedical Research Centre, Churchill Hospital, Oxford OX3 7LE, UK
| | - Sian Ellard
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK, Molecular Genetics Laboratory, Royal Devon and Exeter NHS Foundation Trust, Exeter EX2 5DW, UK
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12
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Yellapu N, Mahto MK, Valasani KR, Sarma P, Matcha B. Mutations in exons 10 and 11 of human glucokinase result in conformational variations in the active site of the structure contributing to poor substrate binding – explains hyperglycemia in type 2 diabetic patients. J Biomol Struct Dyn 2014; 33:820-33. [DOI: 10.1080/07391102.2014.913989] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Nandakumar Yellapu
- Division of Animal Biotechnology, Department of Zoology, Sri Venkateswara University, Tirupati, Andhrapradesh 517502, India
- Biomedical Informatics Center, Vector Control Research Center, Indian Council of Medical Research, Pondicherry, 605006 India
| | - Manoj Kumar Mahto
- Division of Animal Biotechnology, Department of Zoology, Sri Venkateswara University, Tirupati, Andhrapradesh 517502, India
| | - Koteswara Rao Valasani
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, KS, 66047 USA
| | - P.V.G.K. Sarma
- Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhrapradesh, 517507 India
| | - Bhaskar Matcha
- Division of Animal Biotechnology, Department of Zoology, Sri Venkateswara University, Tirupati, Andhrapradesh 517502, India
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13
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Yellapu NK, Valasani KR, Pasupuleti SK, Gopal S, Potukuchi Venkata Gurunadha Krishna S, Matcha B. Identification and analysis of novel R308K mutation in glucokinase of type 2 diabetic patient and its kinetic correlation. Biotechnol Appl Biochem 2014; 61:572-81. [PMID: 24447076 DOI: 10.1002/bab.1209] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Accepted: 01/14/2014] [Indexed: 11/09/2022]
Abstract
Glucokinase (GK) plays a critical role in glucose homeostasis and the mutations in GK gene result in pathogenic complications known as Maturity Onset Diabetes of the Young 2, an autosomal dominant form of diabetic condition. In the present study, GK was purified from human liver tissue and the pure enzyme showed single band in SDS-PAGE with a molecular weight of 50 kDa. The kinetics of pure GK showed enzyme activity of 0.423±0.02 µM glucose-6-phosphate (G6P)/mL/Min and Km value of 6.66±0.02 µM. These values were compared in the liver biopsy of a clinically proven type 2 diabetic patient, where GK kinetics showed decreased enzyme activity of 0.16±0.025 µM G6P/mL/Min and increased Km of 23±0.9 µM, indicating the hyperglycemic condition in the patient. The genetic analysis of 10th exon of GK gene from this patient showed a R308K mutation. To substantiate these results, comparative molecular dynamics and docking studies were carried out where a higher docking score (-10.218 kcal/mol) was observed in the mutated GK than wild-type GK structure (-12.593 kcal/mol) indicating affinity variations for glucose. During the simulation process, glucose was expelled out from the mutant conformation but not from wild-type GK, making glucose unavailable for phosphorylation. Therefore, these results conclusively explain hyperglycemic condition in this patient.
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Affiliation(s)
- Nanda Kumar Yellapu
- Division of Animal Biotechnology, Department of Zoology, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
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14
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Szlyk B, Braun CR, Ljubicic S, Patton E, Bird GH, Osundiji MA, Matschinsky FM, Walensky LD, Danial NN. A phospho-BAD BH3 helix activates glucokinase by a mechanism distinct from that of allosteric activators. Nat Struct Mol Biol 2013; 21:36-42. [PMID: 24317490 DOI: 10.1038/nsmb.2717] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Accepted: 10/15/2013] [Indexed: 01/10/2023]
Abstract
Glucokinase (GK) is a glucose-phosphorylating enzyme that regulates insulin release and hepatic metabolism, and its loss of function is implicated in diabetes pathogenesis. GK activators (GKAs) are attractive therapeutics in diabetes; however, clinical data indicate that their benefits can be offset by hypoglycemia, owing to marked allosteric enhancement of the enzyme's glucose affinity. We show that a phosphomimetic of the BCL-2 homology 3 (BH3) α-helix derived from human BAD, a GK-binding partner, increases the enzyme catalytic rate without dramatically changing glucose affinity, thus providing a new mechanism for pharmacologic activation of GK. Remarkably, BAD BH3 phosphomimetic mediates these effects by engaging a new region near the enzyme's active site. This interaction increases insulin secretion in human islets and restores the function of naturally occurring human GK mutants at the active site. Thus, BAD phosphomimetics may serve as a new class of GKAs.
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Affiliation(s)
- Benjamin Szlyk
- 1] Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA. [2]
| | - Craig R Braun
- 1] Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA. [2]
| | - Sanda Ljubicic
- 1] Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA. [2] Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Elaura Patton
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Gregory H Bird
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Mayowa A Osundiji
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Franz M Matschinsky
- Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Loren D Walensky
- 1] Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA. [2] Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA. [3] Department of Pediatric Oncology, Children's Hospital, Boston, Massachusetts, USA
| | - Nika N Danial
- 1] Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA. [2] Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
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15
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Markwardt ML, Nkobena A, Ding SY, Rizzo MA. Association with nitric oxide synthase on insulin secretory granules regulates glucokinase protein levels. Mol Endocrinol 2012; 26:1617-29. [PMID: 22771492 PMCID: PMC3434526 DOI: 10.1210/me.2012-1183] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 06/19/2012] [Indexed: 11/19/2022] Open
Abstract
Glucokinase (GCK) association with insulin-secretory granules is controlled by interaction with nitric oxide synthase (NOS) and is reversed by GCK S-nitrosylation. Nonetheless, the function of GCK sequestration on secretory granules is unknown. Here we report that the S-nitrosylation blocking V367M mutation prevents GCK accumulation on secretory granules by inhibiting association with NOS. Expression of this mutant is reduced compared with a second S-nitrosylation blocking GCK mutant (C371S) that accumulates to secretory granules and is expressed at levels greater than wild type. Even so, the rate of degradation for wild type and mutant GCK proteins were not significantly different from one another, and neither mutation disrupted the ability of GCK to be ubiquitinated. Furthermore, gene silencing of NOS reduced endogenous GCK content but did not affect β-actin content. Treatment of GCK(C371S) expressing cells with short interfering RNA specific for NOS also blocked accumulation of this protein to secretory granules and reduced expression levels to that of GCK(V367M). Conversely, cotransfection of catalytically inactive NOS increased GCK-mCherry levels. Expression of GCK(C371S) in βTC3 cells enhanced glucose metabolism compared with untransfected cells and cells expressing wild type GCK, even though this mutant has slightly reduced enzymatic activity in vitro. Finally, molecular dynamics simulations revealed that V367M induces conformational changes in GCK that are similar to S-nitrosylated GCK, thereby suggesting a mechanism for V367M-inhibition of NOS association. Our findings suggest that sequestration of GCK on secretory granules regulates cellular GCK protein content, and thus cellular GCK activity, by acting as a storage pool for GCK proteins.
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Affiliation(s)
- Michele L Markwardt
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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16
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Negahdar M, Aukrust I, Johansson BB, Molnes J, Molven A, Matschinsky FM, Søvik O, Kulkarni RN, Flatmark T, Njølstad PR, Bjørkhaug L. GCK-MODY diabetes associated with protein misfolding, cellular self-association and degradation. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1705-15. [PMID: 22820548 DOI: 10.1016/j.bbadis.2012.07.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Revised: 06/17/2012] [Accepted: 07/12/2012] [Indexed: 12/31/2022]
Abstract
GCK-MODY, dominantly inherited mild fasting hyperglycemia, has been associated with >600 different mutations in the glucokinase (GK)-encoding gene (GCK). When expressed as recombinant pancreatic proteins, some mutations result in enzymes with normal/near-normal catalytic properties. The molecular mechanism(s) of GCK-MODY due to these mutations has remained elusive. Here, we aimed to explore the molecular mechanisms for two such catalytically 'normal' GCK mutations (S263P and G264S) in the F260-L270 loop of GK. When stably overexpressed in HEK293 cells and MIN6 β-cells, the S263P- and G264S-encoded mutations generated misfolded proteins with an increased rate of degradation (S263P>G264S) by the protein quality control machinery, and a propensity to self-associate (G264S>S263P) and form dimers (SDS resistant) and aggregates (partly Triton X-100 insoluble), as determined by pulse-chase experiments and subcellular fractionation. Thus, the GCK-MODY mutations S263P and G264S lead to protein misfolding causing destabilization, cellular dimerization/aggregation and enhanced rate of degradation. In silico predicted conformational changes of the F260-L270 loop structure are considered to mediate the dimerization of both mutant proteins by a domain swapping mechanism. Thus, similar properties may represent the molecular mechanisms for additional unexplained GCK-MODY mutations, and may also contribute to the disease mechanism in other previously characterized GCK-MODY inactivating mutations.
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Affiliation(s)
- Maria Negahdar
- Department of Clinical Medicine, University of Bergen, N-5020 Bergen, Norway
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17
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Beer NL, Osbak KK, van de Bunt M, Tribble ND, Steele AM, Wensley KJ, Edghill EL, Colcough K, Barrett A, Valentínová L, Rundle JK, Raimondo A, Grimsby J, Ellard S, Gloyn AL. Insights into the pathogenicity of rare missense GCK variants from the identification and functional characterization of compound heterozygous and double mutations inherited in cis. Diabetes Care 2012; 35:1482-4. [PMID: 22611063 PMCID: PMC3379612 DOI: 10.2337/dc11-2420] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 03/09/2012] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To demonstrate the importance of using a combined genetic and functional approach to correctly interpret a genetic test for monogenic diabetes. RESEARCH DESIGN AND METHODS We identified three probands with a phenotype consistent with maturity-onset diabetes of the young (MODY) subtype GCK-MODY, in whom two potential pathogenic mutations were identified: [R43H/G68D], [E248 K/I225M], or [G261R/D217N]. Allele-specific PCR and cosegregation were used to determine phase. Single and double mutations were kinetically characterized. RESULTS The mutations occurred in cis (double mutants) in two probands and in trans in one proband. Functional studies of all double mutants revealed inactivating kinetics. The previously reported GCK-MODY mutations R43H and G68D were inherited from an affected father and unaffected mother, respectively. Both our functional and genetic studies support R43H as the cause of GCK-MODY and G68D as a neutral rare variant. CONCLUSIONS These data highlight the need for family/functional studies, even for previously reported pathogenic mutations.
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Affiliation(s)
- Nicola L. Beer
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Kara K. Osbak
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
| | - Martijn van de Bunt
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
| | - Nicholas D. Tribble
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
| | - Anna M. Steele
- Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, Exeter, U.K
| | - Kirsty J. Wensley
- Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, Exeter, U.K
| | - Emma L. Edghill
- Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, Exeter, U.K
| | - Kevin Colcough
- Molecular Genetics Department, Royal Devon and Exeter NHS Trust, Exeter, U.K
| | - Amy Barrett
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
| | - Lucia Valentínová
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
- Institute of Experimental Endocrinology, Slovak Academy of Science, Bratislava, Slovakia
| | - Jana K. Rundle
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
| | - Anne Raimondo
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
| | - Joseph Grimsby
- Department of Metabolic Diseases, Hoffmann-La Roche Inc., Nutley, New Jersey
| | - Sian Ellard
- Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, Exeter, U.K
- Molecular Genetics Department, Royal Devon and Exeter NHS Trust, Exeter, U.K
| | - Anna L. Gloyn
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
- Oxford National Institute for Health Research, Churchill Hospital, Oxford, U.K
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18
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Capuano M, Garcia-Herrero CM, Tinto N, Carluccio C, Capobianco V, Coto I, Cola A, Iafusco D, Franzese A, Zagari A, Navas MA, Sacchetti L. Glucokinase (GCK) mutations and their characterization in MODY2 children of southern Italy. PLoS One 2012; 7:e38906. [PMID: 22761713 PMCID: PMC3385652 DOI: 10.1371/journal.pone.0038906] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 05/14/2012] [Indexed: 01/24/2023] Open
Abstract
Type 2 Maturity Onset Diabetes of the Young (MODY2) is a monogenic autosomal disease characterized by a primary defect in insulin secretion and hyperglycemia. It results from GCK gene mutations that impair enzyme activity. Between 2006 and 2010, we investigated GCK mutations in 66 diabetic children from southern Italy with suspected MODY2. Denaturing High Performance Liquid Chromatography (DHPLC) and sequence analysis revealed 19 GCK mutations in 28 children, six of which were novel: p.Glu40Asp, p.Val154Leu, p.Arg447Glyfs, p.Lys458_Cys461del, p.Glu395_Arg397del and c.580-2A>T. We evaluated the effect of these 19 mutations using bioinformatic tools such as Polymorphism Phenotyping (Polyphen), Sorting Intolerant From Tolerant (SIFT) and in silico modelling. We also conducted a functional study to evaluate the pathogenic significance of seven mutations that are among the most severe mutations found in our population, and have never been characterized: p.Glu70Asp, p.His137Asp, p.Phe150Tyr, p.Val154Leu, p.Gly162Asp, p.Arg303Trp and p.Arg392Ser. These seven mutations, by altering one or more kinetic parameters, reduced enzyme catalytic activity by >40%. All mutations except p.Glu70Asp displayed thermal-instability, indeed >50% of enzyme activity was lost at 50°C/30 min. Thus, these seven mutations play a pathogenic role in MODY2 insurgence. In conclusion, this report revealed six novel GCK mutations and sheds some light on the structure-function relationship of human GCK mutations and MODY2.
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Affiliation(s)
- Marina Capuano
- Department of Biochemistry and Medical Biotechnology, University of Naples “Federico II”, Naples, Italy
- Centro di Ingegneria Genetica (CEINGE) Advanced Biotechnology, s. c. a r. l., Naples, Italy
| | - Carmen Maria Garcia-Herrero
- Department of Biochemistry and Molecular Biology III, Faculty of Medicine, Complutense University of Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain
| | - Nadia Tinto
- Department of Biochemistry and Medical Biotechnology, University of Naples “Federico II”, Naples, Italy
- Centro di Ingegneria Genetica (CEINGE) Advanced Biotechnology, s. c. a r. l., Naples, Italy
| | - Carla Carluccio
- Centro di Ingegneria Genetica (CEINGE) Advanced Biotechnology, s. c. a r. l., Naples, Italy
- Department of Biological Science, University of Naples “Federico II”, Naples, Italy
| | - Valentina Capobianco
- Fondazione SDN-IRCSS (Istituto di Diagnostica Nucleare-Istituto di Ricerca e Cura a Carattere Scientifico), Naples, Italy
| | - Iolanda Coto
- Department of Biochemistry and Medical Biotechnology, University of Naples “Federico II”, Naples, Italy
- Centro di Ingegneria Genetica (CEINGE) Advanced Biotechnology, s. c. a r. l., Naples, Italy
| | - Arturo Cola
- Department of Biochemistry and Medical Biotechnology, University of Naples “Federico II”, Naples, Italy
- Centro di Ingegneria Genetica (CEINGE) Advanced Biotechnology, s. c. a r. l., Naples, Italy
| | - Dario Iafusco
- Department of Pediatrics, Second University of Naples, Naples, Italy
| | - Adriana Franzese
- Department of Pediatrics, University of Naples “Federico II”, Naples, Italy
| | - Adriana Zagari
- Centro di Ingegneria Genetica (CEINGE) Advanced Biotechnology, s. c. a r. l., Naples, Italy
- Department of Biological Science, University of Naples “Federico II”, Naples, Italy
| | - Maria Angeles Navas
- Department of Biochemistry and Molecular Biology III, Faculty of Medicine, Complutense University of Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain
| | - Lucia Sacchetti
- Department of Biochemistry and Medical Biotechnology, University of Naples “Federico II”, Naples, Italy
- Centro di Ingegneria Genetica (CEINGE) Advanced Biotechnology, s. c. a r. l., Naples, Italy
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19
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Identification and functional characterisation of novel glucokinase mutations causing maturity-onset diabetes of the young in Slovakia. PLoS One 2012; 7:e34541. [PMID: 22493702 PMCID: PMC3321013 DOI: 10.1371/journal.pone.0034541] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 03/01/2012] [Indexed: 11/19/2022] Open
Abstract
Heterozygous glucokinase (GCK) mutations cause a subtype of maturity-onset diabetes of the young (GCK-MODY). Over 600 GCK mutations have been reported of which ∼65% are missense. In many cases co-segregation has not been established and despite the importance of functional studies in ascribing pathogenicity for missense variants these have only been performed for <10% of mutations. The aim of this study was to determine the minimum prevalence of GCK-MODY amongst diabetic subjects in Slovakia by sequencing GCK in 100 Slovakian probands with a phenotype consistent with GCK-MODY and to explore the pathogenicity of identified variants through family and functional studies. Twenty-two mutations were identified in 36 families (17 missense) of which 7 (I110N, V200A, N204D, G258R, F419S, c.580-2A>C, c.1113-1114delGC) were novel. Parental DNA was available for 22 probands (covering 14/22 mutations) and co-segregation established in all cases. Bioinformatic analysis predicted all missense mutations to be damaging. Nine (I110N, V200A, N204D, G223S, G258R, F419S, V244G, L315H, I436N) mutations were functionally evaluated. Basic kinetic analysis explained pathogenicity for 7 mutants which showed reduced glucokinase activity with relative activity indices (RAI) between 0.6 to <0.001 compared to wild-type GCK (1.0). For the remaining 2 mutants additional molecular mechanisms were investigated. Differences in glucokinase regulatory protein (GKRP) -mediated-inhibition of GCK were observed for both L315H & I436N when compared to wild type (IC(50) 14.6±0.1 mM & 20.3±1.6 mM vs.13.3±0.1 mM respectively [p<0.03]). Protein instability as assessed by thermal lability studies demonstrated that both L315H and I436N show marked thermal instability compared to wild-type GCK (RAI at 55°C 8.8±0.8% & 3.1±0.4% vs. 42.5±3.9% respectively [p<0.001]). The minimum prevalence of GCK-MODY amongst Slovakian patients with diabetes was 0.03%. In conclusion, we have identified 22 GCK mutations in 36 Slovakian probands and demonstrate that combining family, bioinformatic and functional studies can aid the interpretation of variants identified by molecular diagnostic screening.
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20
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Larion M, Miller BG. Homotropic allosteric regulation in monomeric mammalian glucokinase. Arch Biochem Biophys 2012; 519:103-11. [PMID: 22107947 PMCID: PMC3294010 DOI: 10.1016/j.abb.2011.11.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 11/03/2011] [Accepted: 11/04/2011] [Indexed: 11/30/2022]
Abstract
Glucokinase catalyzes the ATP-dependent phosphorylation of glucose, a chemical transformation that represents the rate-limiting step of glycolytic metabolism in the liver and pancreas. Glucokinase is a central regulator of glucose homeostasis as evidenced by its association with two disease states, maturity onset diabetes of the young (MODY) and persistent hyperinsulinemia of infancy (PHHI). Mammalian glucokinase is subject to homotropic allosteric regulation by glucose-the steady-state velocity of glucose-6-phosphate production is not hyperbolic, but instead displays a sigmoidal response to increasing glucose concentrations. The positive cooperativity displayed by glucokinase is intriguing since the enzyme functions as a monomer under physiological conditions and contains only a single binding site for glucose. Despite the existence of several models of kinetic cooperativity in monomeric enzymes, a consensus has yet to be reached regarding the mechanism of allosteric regulation in glucokinase. Experimental evidence collected over the last 45 years by a number of investigators supports a link between cooperativity and slow conformational reorganizations of the glucokinase scaffold. In this review, we summarize advances in our understanding of glucokinase allosteric regulation resulting from recent X-ray crystallographic, pre-equilibrium kinetic and high-resolution nuclear magnetic resonance investigations. We conclude with a brief discussion of unanswered questions regarding the mechanistic basis of kinetic cooperativity in mammalian glucokinase.
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Affiliation(s)
- Mioara Larion
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4390, USA
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21
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Liu Q, Shen Y, Liu S, Weng J, Liu J. Crystal structure of E339K mutated human glucokinase reveals changes in the ATP binding site. FEBS Lett 2011; 585:1175-9. [PMID: 21420961 DOI: 10.1016/j.febslet.2011.03.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 03/11/2011] [Accepted: 03/11/2011] [Indexed: 11/28/2022]
Abstract
Human glucokinase (GK) plays an important role in glucose homeostasis. An E339K mutation in GK was recently found to be associated with hyperglycemia. It showed lower enzyme activity and impaired protein stability compared to the wild-type enzyme. Here, we present the crystal structure of E339K GK in complex with glucose. This mutation results in a conformational change of His416, spatially interfering with adenosine-triphosphate (ATP) binding. Furthermore, Ser411 at the ATP binding site is phosphorylated and then hydrogen bonded with Thr82, physically blocking the ATP binding. These findings provide structural basis for the reduced activity of this mutant.
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Affiliation(s)
- Qiang Liu
- State Key Laboratory of Respiratory Diseases, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China
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22
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Dehghan A, Dupuis J, Barbalic M, Bis JC, Eiriksdottir G, Lu C, Pellikka N, Wallaschofski H, Kettunen J, Henneman P, Baumert J, Strachan DP, Fuchsberger C, Vitart V, Wilson JF, Paré G, Naitza S, Rudock ME, Surakka I, de Geus EJC, Alizadeh BZ, Guralnik J, Shuldiner A, Tanaka T, Zee RYL, Schnabel RB, Nambi V, Kavousi M, Ripatti S, Nauck M, Smith NL, Smith AV, Sundvall J, Scheet P, Liu Y, Ruokonen A, Rose LM, Larson MG, Hoogeveen RC, Freimer NB, Teumer A, Tracy RP, Launer LJ, Buring JE, Yamamoto JF, Folsom AR, Sijbrands EJG, Pankow J, Elliott P, Keaney JF, Sun W, Sarin AP, Fontes JD, Badola S, Astor BC, Hofman A, Pouta A, Werdan K, Greiser KH, Kuss O, Meyer zu Schwabedissen HE, Thiery J, Jamshidi Y, Nolte IM, Soranzo N, Spector TD, Völzke H, Parker AN, Aspelund T, Bates D, Young L, Tsui K, Siscovick DS, Guo X, Rotter JI, Uda M, Schlessinger D, Rudan I, Hicks AA, Penninx BW, Thorand B, Gieger C, Coresh J, Willemsen G, Harris TB, Uitterlinden AG, Järvelin MR, Rice K, Radke D, Salomaa V, van Dijk KW, Boerwinkle E, Vasan RS, Ferrucci L, Gibson QD, Bandinelli S, Snieder H, Boomsma DI, Xiao X, Campbell H, Hayward C, Pramstaller PP, van Duijn CM, Peltonen L, Psaty BM, Gudnason V, Ridker PM, Homuth G, Koenig W, Ballantyne CM, Witteman JCM, Benjamin EJ, Perola M, Chasman DI. Meta-analysis of genome-wide association studies in >80 000 subjects identifies multiple loci for C-reactive protein levels. Circulation 2011; 123:731-8. [PMID: 21300955 PMCID: PMC3147232 DOI: 10.1161/circulationaha.110.948570] [Citation(s) in RCA: 393] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 11/23/2010] [Indexed: 02/07/2023]
Abstract
BACKGROUND C-reactive protein (CRP) is a heritable marker of chronic inflammation that is strongly associated with cardiovascular disease. We sought to identify genetic variants that are associated with CRP levels. METHODS AND RESULTS We performed a genome-wide association analysis of CRP in 66 185 participants from 15 population-based studies. We sought replication for the genome-wide significant and suggestive loci in a replication panel comprising 16 540 individuals from 10 independent studies. We found 18 genome-wide significant loci, and we provided evidence of replication for 8 of them. Our results confirm 7 previously known loci and introduce 11 novel loci that are implicated in pathways related to the metabolic syndrome (APOC1, HNF1A, LEPR, GCKR, HNF4A, and PTPN2) or the immune system (CRP, IL6R, NLRP3, IL1F10, and IRF1) or that reside in regions previously not known to play a role in chronic inflammation (PPP1R3B, SALL1, PABPC4, ASCL1, RORA, and BCL7B). We found a significant interaction of body mass index with LEPR (P<2.9×10(-6)). A weighted genetic risk score that was developed to summarize the effect of risk alleles was strongly associated with CRP levels and explained ≈5% of the trait variance; however, there was no evidence for these genetic variants explaining the association of CRP with coronary heart disease. CONCLUSIONS We identified 18 loci that were associated with CRP levels. Our study highlights immune response and metabolic regulatory pathways involved in the regulation of chronic inflammation.
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Affiliation(s)
- Abbas Dehghan
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
- Member of Netherlands Consortium for Healthy Aging (NCHA) sponsored by Netherlands Genomics Initiative (NGI), Leiden, The Netherlands
| | - Josée Dupuis
- Department of Biostatistics, School of Public Health, Boston University, Boston, MA, USA
- The NHLBI and Boston University’s Framingham Heart Study, Framingham, MA, USA
| | - Maja Barbalic
- Human Genetics Center and Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Joshua C Bis
- Department of Medicine, University of Washington, Seattle, WA USA
| | | | - Chen Lu
- Department of Biostatistics, School of Public Health, Boston University, Boston, MA, USA
| | - Niina Pellikka
- Unit of Public Health Genomics, Department of Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland
| | - Henri Wallaschofski
- Institute of Clinical Chemistry and Laboratory Medicine, University of Greifswald, Germany
| | - Johannes Kettunen
- Department of Human Genetics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Peter Henneman
- Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Jens Baumert
- Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - David P Strachan
- Division of Community Health Sciences, St George's University of London, London, UK
| | - Christian Fuchsberger
- Institute of Genetic Medicine, European Academy Bozen/Bolzano (EURAC), Bolzano, Italy. Affiliated Institute of University of Lübeck, Lübeck, Germany
| | - Veronique Vitart
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, UK
| | - James F Wilson
- Centre for Population Health Sciences, University of Edinburgh, Edinburgh EH89AG, UK
| | - Guillaume Paré
- Center for Cardiovascular Disease Prevention, Harvard Medical School, Boston, MA, USA
| | - Silvia Naitza
- Istituto di Neurogenetica e Neurofarmacologia, Consiglio Nazionale delle Ricerche, Cagliari, Italy
| | - Megan E Rudock
- Department of Epidemiology and Prevention, Wake Forest University School of Medicine, Wake Forest, USA
| | - Ida Surakka
- Institute for Molecular Medicine Finland FIMM, University of Helsinki, Helsinki, Finland
| | - Eco JC de Geus
- Department of Biological Psychology, VU University, Amsterdam, The Netherlands
| | - Behrooz Z Alizadeh
- Unit of Genetic Epidemiology and Bioinformatics, Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jack Guralnik
- Laboratory of Epidemiology, Demography and Biometry, National Institute on Aging, NIH, Bethesda, MD, USA
| | - Alan Shuldiner
- Division of Endocrinology, Diabetes and Nutrition, University of Maryland School of Medicine, Maryland, USA
| | - Toshiko Tanaka
- Clinical Research Branch, National Institute on Aging, Baltimore, Maryland, USA
- Medstar Research Institute, Baltimore MD, USA
| | - Robert YL Zee
- Division of Preventive Medicine, Brigham and Women's Hospital, Boston, USA
| | - Renate B Schnabel
- Department of Medicine, Johannes Gutenberg-University, Mainz, Germany
| | - Vijay Nambi
- Department of Medicine, Baylor College of Medicine and Center for Cardiovascular Prevention, Methodist DeBakey Heart and Vascular Center, Houston, USA
| | - Maryam Kavousi
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
- Member of Netherlands Consortium for Healthy Aging (NCHA) sponsored by Netherlands Genomics Initiative (NGI), Leiden, The Netherlands
| | - Samuli Ripatti
- Institute for Molecular Medicine Finland FIMM, University of Helsinki, Helsinki, Finland
| | - Matthias Nauck
- Institute of Clinical Chemistry and Laboratory Medicine, University of Greifswald, Germany
| | - Nicholas L Smith
- Department of Epidemiology, University of Washington, Seattle, WA, USA
- Seattle Epidemiologic Research and Information Center of the Department of Veterans Affairs Office of Research and Development, Seattle, WA, USA
| | | | - Jouko Sundvall
- Unit of Disease Risk, Department of Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland
| | - Paul Scheet
- Department of Epidemiology, MD Anderson Cancer Center, University of Texas, Houston, Texas, USA
| | - Yongmei Liu
- Department of Epidemiology and Prevention, Wake Forest University School of Medicine, Wake Forest, USA
| | - Aimo Ruokonen
- Department of Clinical Chemistry, University of Oulu, Oulu, Finland
| | - Lynda M Rose
- Division of Preventive Medicine, Brigham and Women's Hospital, Boston, USA
| | - Martin G Larson
- The NHLBI and Boston University’s Framingham Heart Study, Framingham, MA, USA
| | - Ron C Hoogeveen
- Department of Medicine, Baylor College of Medicine and Center for Cardiovascular Prevention, Methodist DeBakey Heart and Vascular Center, Houston, USA
| | - Nelson B Freimer
- Center for Cardiovascular Disease Prevention, Harvard Medical School, Boston, MA, USA
| | - Alexander Teumer
- Interfaculty Institute for Genetics and Functional Genomics, Ernst-Moritz-Arndt-University Greifswald, 17487 Greifswald, Germany
| | - Russell P Tracy
- Departments of Pathology and Biochemistry, Colchester Research Facility, Colchester, VT, USA
| | - Lenore J Launer
- Laboratory of Epidemiology, Demography and Biometry, National Institute on Aging, NIH, Bethesda, MD, USA
| | - Julie E Buring
- Division of Preventive Medicine, Brigham and Women's Hospital, Boston, USA
| | - Jennifer F Yamamoto
- The NHLBI and Boston University’s Framingham Heart Study, Framingham, MA, USA
| | - Aaron R Folsom
- Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, MN, USA
| | - Eric JG Sijbrands
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - James Pankow
- Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, MN, USA
| | - Paul Elliott
- MRC-HPA Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of Public Health, St Mary's Campus, Imperial College London, London, UK
| | - John F Keaney
- The NHLBI and Boston University’s Framingham Heart Study, Framingham, MA, USA
| | - Wei Sun
- Department of Biostatistics, Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
| | - Antti-Pekka Sarin
- Institute for Molecular Medicine Finland FIMM, University of Helsinki, Helsinki, Finland
| | - João D Fontes
- The NHLBI and Boston University’s Framingham Heart Study, Framingham, MA, USA
| | | | - Brad C Astor
- Department of Medicine, Baylor College of Medicine and Center for Cardiovascular Prevention, Methodist DeBakey Heart and Vascular Center, Houston, USA
| | - Albert Hofman
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
- Member of Netherlands Consortium for Healthy Aging (NCHA) sponsored by Netherlands Genomics Initiative (NGI), Leiden, The Netherlands
| | - Anneli Pouta
- Department of Life course and Services, National Institute for Health and Welfare, Helsinki, Finland
| | - Karl Werdan
- Department of Medicine III, Martin-Luther-University Halle-Wittenberg, Germany
| | - Karin H Greiser
- Institute for Medical Epidemiology, Biostatistics, and Informatics, Martin-Luther-University Halle-Wittenberg, Germany
- Division of Cancer Epidemiology, German Cancer Research Centre, Heidelberg, Germany
| | - Oliver Kuss
- Institute for Medical Epidemiology, Biostatistics, and Informatics, Martin-Luther-University Halle-Wittenberg, Germany
| | | | - Joachim Thiery
- Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics (ILM), University of Leipzig, Germany
| | - Yalda Jamshidi
- Division of Clinical Developmental Sciences, St George’s University of London, London, UK
- Department of Twin Research and Genetic Epidemiology Unit, St Thomas’ Campus, King’s College London, St Thomas’ Hospital, London, UK
| | - Ilja M Nolte
- Unit of Genetic Epidemiology and Bioinformatics, Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | | | - Timothy D Spector
- Department of Twin Research and Genetic Epidemiology Unit, King’s College London, United Kingdom
| | - Henry Völzke
- Institute for Community Medicine, Ernst-Moritz-Arndt-Universität Greifswald, Greifswald, Germany
| | | | - Thor Aspelund
- Icelandic Heart Association, Kopavogur, Iceland
- University of Iceland, Reykjavik, Iceland
| | - David Bates
- Division of Preventive Medicine, Brigham and Women's Hospital, Boston, USA
| | | | | | - David S Siscovick
- Cardiovascular Health Research Unit, Departments of Medicine, Epidemiology, and Health Services, University of Washington, Seattle, WA, USA
| | - Xiuqing Guo
- Medical Genetics Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Jerome I Rotter
- Medical Genetics Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Manuela Uda
- Istituto di Neurogenetica e Neurofarmacologia, Consiglio Nazionale delle Ricerche, Cagliari, Italy
| | - David Schlessinger
- Laboratory of Genetics, National Institute on Aging, Baltimore, MD 21224, USA
| | - Igor Rudan
- Centre for Population Health Sciences, University of Edinburgh, Edinburgh EH89AG, UK
- Croatian Centre for Global Health, University of Split Medical School, Split, Croatia
| | - Andrew A Hicks
- Institute of Genetic Medicine, European Academy Bozen/Bolzano (EURAC), Bolzano, Italy. Affiliated Institute of University of Lübeck, Lübeck, Germany
| | - Brenda W Penninx
- Department of Psychiatry/EMGO Institute/Neuroscience Campus, VU University Medical Centre, Amsterdam, The Netherlands
| | - Barbara Thorand
- Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Christian Gieger
- Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Joe Coresh
- Department of Medicine, Baylor College of Medicine and Center for Cardiovascular Prevention, Methodist DeBakey Heart and Vascular Center, Houston, USA
| | - Gonneke Willemsen
- Department of Biological Psychology, VU University, Amsterdam, The Netherlands
| | - Tamara B Harris
- Laboratory of Epidemiology, Demography and Biometry, National Institute on Aging, NIH, Bethesda, MD, USA
| | - Andre G Uitterlinden
- Member of Netherlands Consortium for Healthy Aging (NCHA) sponsored by Netherlands Genomics Initiative (NGI), Leiden, The Netherlands
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Marjo-Riitta Järvelin
- MRC-HPA Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of Public Health, St Mary's Campus, Imperial College London, London, UK
- Department of Life course and Services, National Institute for Health and Welfare, Helsinki, Finland
- Institute of Health Sciences and Biocenter Oulu, Faculty of Medicine, University of Oulu, Oulu, Finland
| | - Kenneth Rice
- Department of Biostatistics, University of Washington, Seattle, WA, USA
| | - Dörte Radke
- Institute for Community Medicine, Ernst-Moritz-Arndt-Universität Greifswald, Greifswald, Germany
| | - Veikko Salomaa
- Unit of Chronic Disease Epidemiology and Prevention, Department of Chronic Disease Prevention , National Institute for Health and Welfare, Helsinki, Finland
| | - Ko Willems van Dijk
- Departments of Internal Medicine and Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Eric Boerwinkle
- Human Genetics Center and Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Ramachandran S Vasan
- The NHLBI and Boston University’s Framingham Heart Study, Framingham, MA, USA
- Preventive Medicine and Cardiology Sections, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Luigi Ferrucci
- Clinical Research Branch, National Institute on Aging, Baltimore, Maryland, USA
| | - Quince D Gibson
- Division of Endocrinology, Diabetes and Nutrition, University of Maryland School of Medicine, Maryland, USA
| | | | - Harold Snieder
- Unit of Genetic Epidemiology and Bioinformatics, Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Dorret I Boomsma
- Department of Biological Psychology, VU University, Amsterdam, The Netherlands
| | - Xiangjun Xiao
- Department of Epidemiology, MD Anderson Cancer Center, University of Texas, Houston, Texas, USA
| | - Harry Campbell
- Centre for Population Health Sciences, University of Edinburgh, Edinburgh EH89AG, UK
| | - Caroline Hayward
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, UK
| | - Peter P Pramstaller
- Institute of Genetic Medicine, European Academy Bozen/Bolzano (EURAC), Bolzano, Italy. Affiliated Institute of University of Lübeck, Lübeck, Germany
- Department of Neurology, General Central Hospital, Bolzano, Italy
- Department of Neurology, University of Lübeck, Lübeck, Germany
| | - Cornelia M van Duijn
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
- Member of Netherlands Consortium for Healthy Aging (NCHA) sponsored by Netherlands Genomics Initiative (NGI), Leiden, The Netherlands
| | - Leena Peltonen
- Department of Human Genetics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Bruce M Psaty
- Cardiovascular Health Research Unit, Departments of Medicine, Epidemiology, and Health Services, University of Washington, Seattle, WA, USA
- Group Health Research Institute, Group Health Cooperative, Seattle, WA, USA
| | - Vilmundur Gudnason
- Icelandic Heart Association, Kopavogur, Iceland
- University of Iceland, Reykjavik, Iceland
| | - Paul M Ridker
- Division of Preventive Medicine, Brigham and Women's Hospital, Boston, USA
| | - Georg Homuth
- Interfaculty Institute for Genetics and Functional Genomics, Ernst-Moritz-Arndt-University Greifswald, 17487 Greifswald, Germany
| | - Wolfgang Koenig
- Department of Internal Medicine II - Cardiology, University of Ulm Medical Center, Ulm, Germany
| | - Christie M Ballantyne
- Department of Medicine, Baylor College of Medicine and Center for Cardiovascular Prevention, Methodist DeBakey Heart and Vascular Center, Houston, USA
| | - Jacqueline CM Witteman
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
- Member of Netherlands Consortium for Healthy Aging (NCHA) sponsored by Netherlands Genomics Initiative (NGI), Leiden, The Netherlands
| | - Emelia J Benjamin
- The NHLBI and Boston University’s Framingham Heart Study, Framingham, MA, USA
- Preventive Medicine and Cardiology Sections, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Markus Perola
- Unit of Public Health Genomics, Department of Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland
| | - Daniel I Chasman
- Division of Preventive Medicine, Brigham and Women's Hospital, Boston, USA
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23
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Insight into the biochemical characteristics of a novel glucokinase gene mutation. Hum Genet 2010; 129:231-8. [DOI: 10.1007/s00439-010-0914-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Accepted: 11/05/2010] [Indexed: 10/18/2022]
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24
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Ralph EC, Sun S. Biochemical characterization of MODY2 glucokinase variants V62M and G72R reveals reduced enzymatic activities relative to wild type. Biochemistry 2010; 48:2514-21. [PMID: 19187021 DOI: 10.1021/bi900020n] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The glucokinase V62M and G72R mutations are naturally occurring and known to associate with hyperglycemia in humans. Structurally, V62 and G72 residues are located in close proximity to the allosteric site where hypoglycemia-linked activating mutations are clustered. To address the mechanism by which these variants alter the physiological phenotype, we characterized the biochemical and biophysical properties of the enzymes. Recombinant proteins were purified without affinity tags, and their steady-state kinetics and glucose binding affinities were determined. Both enzymes showed reduced rates of turnover (k(cat)) and reduced glucose affinity (i.e., increased K(0.5) and K(D) values). Their thermal stability did not largely differ from that of wild-type glucokinase. However, V62M and G72R lost the stabilizing protein interactions with glucokinase regulatory protein, which may contribute to lower activity in vivo. Both mutants were subject to activation by small molecule activators. In conclusion, the decreased enzyme activities of V62M and G72R observed in this study are consistent with the hyperglycemic phenotype.
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Affiliation(s)
- Erik C Ralph
- Department of Biochemical Pharmacology, La Jolla Laboratories, Pfizer Global Research and Development, San Diego, California 92121, USA
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25
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Osbak KK, Colclough K, Saint-Martin C, Beer NL, Bellanné-Chantelot C, Ellard S, Gloyn AL. Update on mutations in glucokinase (GCK), which cause maturity-onset diabetes of the young, permanent neonatal diabetes, and hyperinsulinemic hypoglycemia. Hum Mutat 2010; 30:1512-26. [PMID: 19790256 DOI: 10.1002/humu.21110] [Citation(s) in RCA: 339] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Glucokinase is a key regulatory enzyme in the pancreatic beta-cell. It plays a crucial role in the regulation of insulin secretion and has been termed the glucose sensor in pancreatic beta-cells. Given its central role in the regulation of insulin release it is understandable that mutations in the gene encoding glucokinase (GCK) can cause both hyper- and hypoglycemia. Heterozygous inactivating mutations in GCK cause maturity-onset diabetes of the young (MODY) subtype glucokinase (GCK), characterized by mild fasting hyperglycemia, which is present at birth but often only detected later in life during screening for other purposes. Homozygous inactivating GCK mutations result in a more severe phenotype presenting at birth as permanent neonatal diabetes mellitus (PNDM). A growing number of heterozygous activating GCK mutations that cause hypoglycemia have also been reported. A total of 620 mutations in the GCK gene have been described in a total of 1,441 families. There are no common mutations, and the mutations are distributed throughout the gene. The majority of activating mutations cluster in a discrete region of the protein termed the allosteric activator site. The identification of a GCK mutation in patients with both hyper- and hypoglycemia has implications for the clinical course and clinical management of their disorder.
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Affiliation(s)
- Kara K Osbak
- Diabetes Research Laboratories, Oxford Centre for Diabetes Endocrinology & Metabolism, University of Oxford, United Kingdom
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26
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Pino MF, Kim KA, Shelton KD, Lindner J, Odili S, Li C, Collins HW, Shiota M, Matschinsky FM, Magnuson MA. Glucokinase Thermolability and Hepatic Regulatory Protein Binding Are Essential Factors for Predicting the Blood Glucose Phenotype of Missense Mutations. J Biol Chem 2007; 282:13906-16. [PMID: 17353190 DOI: 10.1074/jbc.m610094200] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To better understand how glucokinase (GK) missense mutations associated with human glycemic diseases perturb glucose homeostasis, we generated and characterized mice with either an activating (A456V) or inactivating (K414E) mutation in the gk gene. Animals with these mutations exhibited alterations in their blood glucose concentration that were inversely related to the relative activity index of GK. Moreover, the threshold for glucose-stimulated insulin secretion from islets with either the activating or inactivating mutation were left- or right-shifted, respectively. However, we were surprised to find that mice with the activating mutation had markedly reduced amounts of hepatic GK activity. Further studies of bacterially expressed mutant enzymes revealed that GK(A456V) is as stable as the wild type enzyme, whereas GK(K414E) is thermolabile. However, the ability of GK regulatory protein to inhibit GK(A456V) was found to be less than that of the wild type enzyme, a finding consistent with impaired hepatic nuclear localization. Taken together, this study indicates that it is necessary to have knowledge of both thermolability and the interactions of mutant GK enzymes with GK regulatory protein when attempting to predict in vivo glycemic phenotypes based on the measurement of enzyme kinetics.
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Affiliation(s)
- Maria F Pino
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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García-Herrero CM, Galán M, Vincent O, Flández B, Gargallo M, Delgado-Alvarez E, Blázquez E, Navas MA. Functional analysis of human glucokinase gene mutations causing MODY2: exploring the regulatory mechanisms of glucokinase activity. Diabetologia 2007; 50:325-33. [PMID: 17186219 DOI: 10.1007/s00125-006-0542-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Accepted: 10/21/2006] [Indexed: 11/26/2022]
Abstract
AIMS/HYPOTHESIS Glucokinase (GCK) acts as a glucose sensor in the pancreatic beta cell and regulates insulin secretion. In the gene encoding GCK the heterozygous mutations that result in enzyme inactivation cause MODY2. Functional studies of naturally occurring GCK mutations associated with hyperglycaemia provide further insight into the biochemical basis of glucose sensor regulation. MATERIALS AND METHODS Identification of GCK mutations in selected MODY patients was performed by single-strand conformation polymorphism and direct sequencing. The kinetic parameters and thermal stability of recombinant mutant human GCK were determined, and in pull-down assays the effect of these mutations on the association of GCK with glucokinase (hexokinase 4) regulator (GCKR, also known as glucokinase regulatory protein [GKRP]) and 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB1, also known as PFK2) was tested. RESULTS We identified three novel GCK mutations: the insertion of an asparagine residue at position 161 (inserN161) and two missense mutations (M235V and R308W). We also identified a fourth mutation (R397L) reported in a previous work. Functional characterisation of these mutations revealed that insertion of asparagine residue N161 fully inactivates GCK, whereas the M235V and R308W mutations only partially impair enzymatic activity. In contrast, GCK kinetics was almost unaffected by the R397L mutation. Although none of these mutations affected the interaction of GCK with PFKFB1, we found that the R308W mutation caused protein instability and increased the strength of interaction with GCKR. CONCLUSIONS/INTERPRETATION Our results show that different MODY2 mutations impair GCK function through different mechanisms such as enzymatic activity, protein stability and increased interaction with GCKR, helping further elucidate the regulation of GCK activity.
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Affiliation(s)
- C M García-Herrero
- Department of Biochemistry and Molecular Biology III, Faculty of Medicine, Complutense University of Madrid, Madrid, Spain
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28
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Zelent D, Golson ML, Koeberlein B, Quintens R, van Lommel L, Buettger C, Weik-Collins H, Taub R, Grimsby J, Schuit F, Kaestner KH, Matschinsky FM. A glucose sensor role for glucokinase in anterior pituitary cells. Diabetes 2006; 55:1923-9. [PMID: 16804059 DOI: 10.2337/db06-0151] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Enzymatic activity of glucokinase was demonstrated, quantitated, and characterized kinetically in rat and mouse pituitary extracts using a highly specific and sensitive spectrometric assay. A previously proposed hypothesis that the glucokinase gene might be expressed in the pituitary corticotrophic cells was therefore reexamined using mRNA in situ hybridization and immunohistochemical techniques. No evidence was found that corticotrophs are glucokinase positive, and the identity of glucokinase-expressing cells remains to be determined. The findings do, however, suggest a novel hypothesis that a critical subgroup of anterior pituitary cells might function as glucose sensor cells and that direct fuel regulation of such cells may modify the classical indirect neuroendocrine pathways that are known to control hormone secretion from anterior pituitary cells.
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Affiliation(s)
- Dorothy Zelent
- University of Pennsylvania School of Medicine, BiochemistryBiophysics, 501 Stemmler Hall, 36th & Hamilton Walk, Philadelphia, PA 19104, USA
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29
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Sagen JV, Odili S, Bjørkhaug L, Zelent D, Buettger C, Kwagh J, Stanley C, Dahl-Jørgensen K, de Beaufort C, Bell GI, Han Y, Grimsby J, Taub R, Molven A, Søvik O, Njølstad PR, Matschinsky FM. From clinicogenetic studies of maturity-onset diabetes of the young to unraveling complex mechanisms of glucokinase regulation. Diabetes 2006; 55:1713-22. [PMID: 16731834 DOI: 10.2337/db05-1513] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Glucokinase functions as a glucose sensor in pancreatic beta-cells and regulates hepatic glucose metabolism. A total of 83 probands were referred for a diagnostic screening of mutations in the glucokinase (GCK) gene. We found 11 different mutations (V62A, G72R, L146R, A208T, M210K, Y215X, S263P, E339G, R377C, S453L, and IVS5 + 1G>C) in 14 probands. Functional characterization of recombinant glutathionyl S-transferase-G72R glucokinase showed slightly increased activity, whereas S263P and G264S had near-normal activity. The other point mutations were inactivating. S263P showed marked thermal instability, whereas the stability of G72R and G264S differed only slightly from that of wild type. G72R and M210K did not respond to an allosteric glucokinase activator (GKA) or the hepatic glucokinase regulatory protein (GKRP). Mutation analysis of the role of glycine at position 72 by substituting E, F, K, M, S, or Q showed that G is unique since all these mutants had very low or no activity and were refractory to GKRP and GKA. Structural analysis provided plausible explanations for the drug resistance of G72R and M210K. Our study provides further evidence that protein instability in combination with loss of control by a putative endogenous activator and GKRP could be involved in the development of hyperglycemia in maturity-onset diabetes of the young, type 2. Furthermore, based on data obtained on G264S, we propose that other and still unknown mechanisms participate in the regulation of glucokinase.
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Affiliation(s)
- Jørn V Sagen
- Section for Pediatrics, Department of Clinical Medicine, University of Bergen, Bergen, Norway
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30
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Galán M, Vincent O, Roncero I, Azriel S, Boix-Pallares P, Delgado-Alvarez E, Díaz-Cadórniga F, Blázquez E, Navas MA. Effects of novel maturity-onset diabetes of the young (MODY)-associated mutations on glucokinase activity and protein stability. Biochem J 2006; 393:389-96. [PMID: 16173921 PMCID: PMC1383698 DOI: 10.1042/bj20051137] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2005] [Revised: 08/26/2005] [Accepted: 09/21/2005] [Indexed: 12/13/2022]
Abstract
Glucokinase acts as the pancreatic glucose sensor and plays a critical role in the regulation of insulin secretion by the beta-cell. Heterozygous mutations in the glucokinase-encoding GCK gene, which result in a reduction of the enzymatic activity, cause the monogenic form of diabetes, MODY2 (maturity-onset diabetes of the young 2). We have identified and functionally characterized missense mutations in the GCK gene in diabetic families that result in protein mutations Leu165-->Phe, Glu265-->Lys and Thr206-->Met. The first two are novel GCK mutations that co-segregate with the diabetes phenotype in their respective families and are not found in more than 50 healthy control individuals. In order to measure the biochemical effects of these missense mutations on glucokinase activity, we bacterially expressed and affinity-purified islet human glucokinase proteins carrying the respective mutations and fused to GST (glutathione S-transferase). Enzymatic assays on the recombinant proteins revealed that mutations Thr206-->Met and Leu165-->Phe strongly affect the kinetic parameters of glucokinase, in agreement with the localization of both residues close to the active site of the enzyme. In contrast, mutation Glu265-->Lys, which has a weaker effect on the kinetics of glucokinase, strongly affects the protein stability, suggesting a possible structural defect of this mutant protein. Finally, none of the mutations tested appears to affect the interaction of gluco-kinase with the glucokinase regulatory protein in the yeast two-hybrid system.
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Key Words
- diabetes mellitus
- enzyme kinetics
- gck gene
- glucokinase
- inactivating mutation
- maturity-onset diabetes of the young (mody)
- dtt, dithiothreitol
- gk, glucokinase
- gkrp, gk regulatory protein
- glcnac, n-acetylglucosamine
- g6p, glucose 6-phosphate
- gst, glutathione s-transferase
- ia, activity index
- mh, mannoheptulose
- mody, maturity-onset diabetes of the young
- ogtt, oral glucose tolerance test
- sd medium, synthetic dextrose minimal
- sscp, single-strand conformation polymorphism
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Affiliation(s)
- María Galán
- *Departamento de Bioquímica y Biología Molecular III, Facultad de Medicina, Universidad Complutense de Madrid, Ciudad Universitaria, Madrid 28040, Spain
| | - Olivier Vincent
- †Departamento de Microbiología Molecular, Centro de Investigaciones Biológicas del CSIC, Madrid 28040, Spain
| | - Isabel Roncero
- *Departamento de Bioquímica y Biología Molecular III, Facultad de Medicina, Universidad Complutense de Madrid, Ciudad Universitaria, Madrid 28040, Spain
| | - Sharona Azriel
- ‡Servicio de Endocrinología, Hospital 12 de Octubre, Av. de Córdoba s/n, Madrid 28041, Spain
| | - Pedro Boix-Pallares
- §Servicio de Endocrinología, Hospital General de Asturias, Julián Clavería s/n, Oviedo 33006, Spain
| | - Elías Delgado-Alvarez
- §Servicio de Endocrinología, Hospital General de Asturias, Julián Clavería s/n, Oviedo 33006, Spain
| | - Francisco Díaz-Cadórniga
- §Servicio de Endocrinología, Hospital General de Asturias, Julián Clavería s/n, Oviedo 33006, Spain
| | - Enrique Blázquez
- *Departamento de Bioquímica y Biología Molecular III, Facultad de Medicina, Universidad Complutense de Madrid, Ciudad Universitaria, Madrid 28040, Spain
| | - María-Angeles Navas
- *Departamento de Bioquímica y Biología Molecular III, Facultad de Medicina, Universidad Complutense de Madrid, Ciudad Universitaria, Madrid 28040, Spain
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32
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Marotta DE, Anand GR, Anderson TA, Miller SP, Okar DA, Levitt DG, Lange AJ. Identification and characterization of the ATP-binding site in human pancreatic glucokinase. Arch Biochem Biophys 2005; 436:23-31. [PMID: 15752705 DOI: 10.1016/j.abb.2005.01.018] [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] [Received: 09/09/2004] [Revised: 01/19/2005] [Indexed: 11/25/2022]
Abstract
The central role of human pancreatic glucokinase in insulin secretion and, consequently, in maintenance of blood glucose levels has prompted investigation into identification of ATP-binding site residues and examination of ATP- and glucose-binding interactions. Because glucokinase has been resistant to crystallization, computer generated homology models were developed based on the X-ray crystal structure of the COOH-terminal domain of human brain hexokinase 1 bound to glucose and ADP or glucose and glucose-6-phosphate. Human pancreatic glucokinase mutants were designed based upon these models and on ATPase domain sequence conservation to identify and characterize potential glucose and ATP-binding sites. Specifically, mutants Asp78Ala, Thr82Ala, Lys90Ala, Lys102Ala, Gly227Ala, Thr228Ala, Ser336Leu, Ser411Ala, and Ser411Leu were constructed, expressed, purified, and kinetically characterized under steady-state conditions. Compared to their respective wild type controls, several mutants demonstrated dramatic changes in V(max), cooperativity of glucose binding and S(0.5) for ATP and glucose. Results suggest a role for Asp78, Thr82, Gly227, Thr228, and Ser336 in ATP binding and indicate these residues are essential for glucose phosphorylation by human pancreatic glucokinase.
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Affiliation(s)
- Diane E Marotta
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
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33
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Gloyn AL, Odili S, Zelent D, Buettger C, Castleden HAJ, Steele AM, Stride A, Shiota C, Magnuson MA, Lorini R, d'Annunzio G, Stanley CA, Kwagh J, van Schaftingen E, Veiga-da-Cunha M, Barbetti F, Dunten P, Han Y, Grimsby J, Taub R, Ellard S, Hattersley AT, Matschinsky FM. Insights into the structure and regulation of glucokinase from a novel mutation (V62M), which causes maturity-onset diabetes of the young. J Biol Chem 2005; 280:14105-13. [PMID: 15677479 DOI: 10.1074/jbc.m413146200] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glucokinase (GCK) serves as the pancreatic glucose sensor. Heterozygous inactivating GCK mutations cause hyperglycemia, whereas activating mutations cause hypoglycemia. We studied the GCK V62M mutation identified in two families and co-segregating with hyperglycemia to understand how this mutation resulted in reduced function. Structural modeling locates the mutation close to five naturally occurring activating mutations in the allosteric activator site of the enzyme. Recombinant glutathionyl S-transferase-V62M GCK is paradoxically activated rather than inactivated due to a decreased S0.5 for glucose compared with wild type (4.88 versus 7.55 mM). The recently described pharmacological activator (RO0281675) interacts with GCK at this site. V62M GCK does not respond to RO0281675, nor does it respond to the hepatic glucokinase regulatory protein (GKRP). The enzyme is also thermally unstable, but this lability is apparently less pronounced than in the proven instability mutant E300K. Functional and structural analysis of seven amino acid substitutions at residue Val62 has identified a non-linear relationship between activation by the pharmacological activator and the van der Waals interactions energies. Smaller energies allow a hydrophobic interaction between the activator and glucokinase, whereas larger energies prohibit the ligand from fitting into the binding pocket. We conclude that V62M may cause hyperglycemia by a complex defect of GCK regulation involving instability in combination with loss of control by a putative endogenous activator and/or GKRP. This study illustrates that mutations that cause hyperglycemia are not necessarily kinetically inactivating but may exert their effects by other complex mechanisms. Elucidating such mechanisms leads to a deeper understanding of the GCK glucose sensor and the biochemistry of beta-cells and hepatocytes.
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Affiliation(s)
- Anna L Gloyn
- Diabetes Research Laboratories, Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford OX3 7LJ, United Kingdom
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34
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Gloyn AL. Glucokinase (GCK) mutations in hyper- and hypoglycemia: maturity-onset diabetes of the young, permanent neonatal diabetes, and hyperinsulinemia of infancy. Hum Mutat 2004; 22:353-62. [PMID: 14517946 DOI: 10.1002/humu.10277] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Glucokinase is a key regulatory enzyme in the pancreatic beta-cell. It plays a crucial role in the regulation of insulin secretion and has been termed the pancreatic beta-cell sensor. Given its central role in the regulation of insulin release, it is understandable that mutations in the gene encoding glucokinase (GCK) can cause both hyperglycemia and hypoglycemia. Heterozygous inactivating mutations in GCK cause maturity-onset diabetes of the young (MODY), characterized by mild hyperglycemia, which is present at birth, but is often only detected later in life during screening for other purposes. Homozygous inactivating GCK mutations result in a more severe phenotype, presenting at birth as permanent neonatal diabetes mellitus (PNDM). Several heterozygous activating GCK mutations that cause hypoglycemia have also been reported. A total of 195 mutations in the GCK gene have been described, in a total of 285 families. There are no common mutations and the mutations are distributed throughout the gene. Mutations that cause hypoglycemia are located in various exons in a discrete region of the protein termed the heterotropic allosteric activator site. The identification of a GCK mutation in hyper- and hypoglycemia has implications for the clinical course and clinical management of the disorder.
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Affiliation(s)
- Anna L Gloyn
- Diabetes and Vascular Medicine, Peninsula Medical School, Exeter, UK.
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35
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Affiliation(s)
- Mark A Magnuson
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37205, USA.
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36
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Abstract
Glucokinase (GK) serves as glucose sensor in pancreatic beta-cells and in other glucose sensor cells in the body. Biochemical genetic studies have characterized many activating and inactivating GK mutants that have been discovered in patients with hyperinsulinemic hypoglycemia or diabetes, all inherited as autosomal dominant traits. Mathematical modeling of the kinetic data of recombinant human wild-type and mutant GK accurately predicts the effects of GK mutations on the threshold of glucose-stimulated insulin release and glucose homeostasis. Structure/function studies of the enzyme suggest the existence of a hitherto unknown allosteric activator site of the enzyme that has significant implications for the physiological chemistry of GK-containing cells, particularly the pancreatic beta-cells. Glucose is the preeminent positive regulator of beta-cell GK expression and involves molecular mechanisms that are still to be elucidated in detail, but seem to have a specific requirement for increased glucose metabolism. Pharmaceutical chemists, motivated by the clear tenets of the GK glucose-sensor paradigm, have searched for and have discovered a novel class of GK activator molecules. The therapeutic application of this basic discovery offers a new principle for drug therapy of diabetes.
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Affiliation(s)
- Franz M Matschinsky
- Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
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37
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Brissova M, Shiota M, Nicholson WE, Gannon M, Knobel SM, Piston DW, Wright CVE, Powers AC. Reduction in pancreatic transcription factor PDX-1 impairs glucose-stimulated insulin secretion. J Biol Chem 2002; 277:11225-32. [PMID: 11781323 DOI: 10.1074/jbc.m111272200] [Citation(s) in RCA: 311] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Complete lack of transcription factor PDX-1 leads to pancreatic agenesis, whereas heterozygosity for PDX-1 mutations has been recently noted in some individuals with maturity-onset diabetes of the young (MODY) and in some individuals with type 2 diabetes. To determine how alterations in PDX-1 affect islet function, we examined insulin secretion and islet physiology in mice with one PDX-1 allele inactivated. PDX-1(+/-) mice had a normal fasting blood glucose and pancreatic insulin content but had impaired glucose tolerance and secreted less insulin during glucose tolerance testing. The expression of PDX-1 and glucose transporter 2 in islets from PDX-1(+/-) mice was reduced to 68 and 55%, respectively, whereas glucokinase expression was not significantly altered. NAD(P)H generation in response to glucose was reduced by 30% in PDX-1(+/-) mice. The in situ perfused pancreas of PDX-1(+/-) mice secreted about 45% less insulin when stimulated with 16.7 mm glucose. The K(m) for insulin release was similar in wild type and PDX-1(+/-) mice. Insulin secretion in response to 20 mm arginine was unchanged; the response to 10 nm glucagon-like peptide-1 was slightly increased. However, insulin secretory responses to 10 mm 2-ketoisocaproate and 20 mm KCl were significantly reduced (by 61 and 66%, respectively). These results indicate that a modest reduction in PDX-1 impairs several events in glucose-stimulated insulin secretion (such as NAD(P)H generation, mitochondrial function, and/or mobilization of intracellular Ca(2+)) and that PDX-1 is important for normal function of adult pancreatic islets.
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Affiliation(s)
- Marcela Brissova
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee 37212, USA
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38
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39
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Burke CV, Buettger CW, Davis EA, McClane SJ, Matschinsky FM, Raper SE. Cell-biological assessment of human glucokinase mutants causing maturity-onset diabetes of the young type 2 (MODY-2) or glucokinase-linked hyperinsulinaemia (GK-HI). Biochem J 1999; 342 ( Pt 2):345-52. [PMID: 10455021 PMCID: PMC1220471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Mutations in the glucokinase (GK) gene cause type-2 maturity-onset diabetes of the young type 2 (MODY-2) and GK-linked hyperinsulinaemia (GK-HI). Recombinant adenoviruses expressing the human wild-type islet GK or one of four mutant forms of GK, (the MODY-2 mutants E70K, E300K and V203A and the GK-HI mutant V455M) were transduced into glucose-responsive insulin-secreting beta-HC9 cells and tested functionally in order to initiate the first analysis in vivo of recombinant wild-type and mutant human islet GK. Kinetic analysis of wild-type human GK showed that the glucose S(0. 5) and Hill coefficient were similar to previously published data in vitro (S(0.5) is the glucose level at the half-maximal rate). E70K had half the glucose affinity of wild-type, but similar enzyme activity. V203A demonstrated decreased catalytic activity and an 8-fold increase in glucose S(0.5) when compared with wild-type human islet GK. E300K had a glucose S(0.5) similar to wild-type but a 10-fold reduction in enzyme activity. E300K mRNA levels were comparable with wild-type GK mRNA levels, but Western-blot analyses demonstrated markedly reduced levels of immunologically detectable protein, consistent with an instability mutation. V455M was just as active as wild-type GK, but with a markedly reduced S(0.5). The effects of the different GK mutants on glucose-stimulated insulin release support the kinetic and expression data. These experiments show the utility of a combined genetic, biochemical and cell-biological approach to the quantification of functional and structural changes of human GK that result from MODY-2 and GK-HI mutations.
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Affiliation(s)
- C V Burke
- Harrison Department of Surgical Research, University of Pennsylvania Medical Center, 313 Stemmler Hall, 36th and Hamilton Walk, Philadelphia, PA 19104, USA
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40
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Dufresne CP, Wood TD, Hendrickson CL. High-resolution electrospray ionization Fourier transform mass spectrometry with infrared multiphoton dissociation of glucokinase from Bacillus Stearothermophilus. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 1998; 9:1222-1225. [PMID: 9794087 DOI: 10.1016/s1044-0305(98)00102-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Glucokinase (GK, EC 2.7.1.2), a member of the enzyme family of hexokinases, has been shown to be linked to maturity-onset diabetes of the young type II (MODY-2). Although nucleotide and amino acid sequence information are available for the human varieties, they are not known for the variety from Bacillus stearothermophilus, which is often used in protein binding studies. Here, a combination of electrospray Fourier transform mass spectrometry (FTMS) and infrared multiphoton dissociation (IRMPD) is used to obtain accurate molecular weight and preliminary amino acid sequence information for the protein. Electrospray FTMS provides evidence of a solution phase dimer. In addition, dithiothreitol reduction shows no shift in high-resolution isotopic distributions, indicating a probable absence of disulfide bonds in the protein. The partial sequence information obtained from IRMPD could be the basis for creating a DNA probe for the protein.
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Affiliation(s)
- C P Dufresne
- Department of Chemistry, State University of New York at Buffalo 14260-3000, USA
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41
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Glaser B, Kesavan P, Heyman M, Davis E, Cuesta A, Buchs A, Stanley CA, Thornton PS, Permutt MA, Matschinsky FM, Herold KC. Familial hyperinsulinism caused by an activating glucokinase mutation. N Engl J Med 1998; 338:226-30. [PMID: 9435328 DOI: 10.1056/nejm199801223380404] [Citation(s) in RCA: 430] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- B Glaser
- Department of Endocrinology and Metabolism, Hebrew University Hadassah Medical School, Jerusalem, Israel
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42
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Matschinsky FM, Collins HW. Essential biochemical design features of the fuel-sensing system in pancreatic beta-cells. CHEMISTRY & BIOLOGY 1997; 4:249-57. [PMID: 9235288 DOI: 10.1016/s1074-5521(97)90068-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The beta-cells of the pancreas control the blood levels of glucose and other nutrients by secreting insulin. They sense blood nutrient levels not by using a classical receptor-signaling system, but by detecting the products of nutrient metabolism. Mutations in this pathway can cause diabetes or hypoglycemia.
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Affiliation(s)
- F M Matschinsky
- Diabetes Research Center, University of Pennsylvania School of Medicine, 501 Stemmler Hall, 36th and Hamilton Walk, Philadelphia, PA 19104-6015, USA
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