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Zhao Y, Ma Y, Ba T, Han X, Ren Q, Ji L. Hypoglycemic Response to Dorzagliatin in a Patient With GCK-MODY. Diabetes Care 2024; 47:1140-1142. [PMID: 38691834 DOI: 10.2337/dc23-2417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Accepted: 04/02/2024] [Indexed: 05/03/2024]
Abstract
OBJECTIVE Metformin, insulin, and insulin secretagogues do not alter HbA1c levels in glucokinase maturity-onset diabetes of the young (GCK-MODY). However, the efficacy of the new hypoglycemic drugs on GCK-MODY remains unclear. RESEARCH DESIGN AND METHODS We describe a case of GCK-MODY with unchanged blood glucose under different therapies during an 8 years' follow-up. His HbA1c and biochemical indices under different hypoglycemic treatments were recorded. RESULTS Oral glucose-lowering drugs, including thiazolidinediones, dipeptidyl peptidase 4 inhibitor, α-glucosidase inhibitor, and sodium-glucose cotransporter 2 inhibitor that had not been evaluated previously, did not improve the HbA1c level in this patient. However, the glucokinase activator dorzagliatin effectively and safely lowered his HbA1c level. CONCLUSIONS Dorzagliatin was effective and safe in this patient with GCK-MODY, providing potential application prospects for precise treatment of GCK-MODY with dorzagliatin.
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Affiliation(s)
- Yilin Zhao
- Department of Endocrinology and Metabolism, Peking University People's Hospital, Beijing, People's Republic of China
| | - Yumin Ma
- Department of Endocrinology and Metabolism, Peking University People's Hospital, Beijing, People's Republic of China
| | - Tianhao Ba
- Department of Endocrinology and Metabolism, Peking University People's Hospital, Beijing, People's Republic of China
| | - Xueyao Han
- Department of Endocrinology and Metabolism, Peking University People's Hospital, Beijing, People's Republic of China
| | - Qian Ren
- Department of Endocrinology and Metabolism, Peking University People's Hospital, Beijing, People's Republic of China
| | - Linong Ji
- Department of Endocrinology and Metabolism, Peking University People's Hospital, Beijing, People's Republic of China
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Khajavi N, Riçku K, Schreier PCF, Gentz T, Beyerle P, Cruz E, Breit A, Reinach PS, Gudermann T. Chronic Mg 2+ Deficiency Does Not Impair Insulin Secretion in Mice. Cells 2023; 12:1790. [PMID: 37443824 PMCID: PMC10340716 DOI: 10.3390/cells12131790] [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: 06/02/2023] [Revised: 06/28/2023] [Accepted: 07/03/2023] [Indexed: 07/15/2023] Open
Abstract
Magnesium is an essential mediator of a vast number of critical enzymatic cellular reactions in the human body. Some clinical epidemiological studies suggest that hypomagnesemia accounts for declines in insulin secretion in patients with type 2 diabetes (T2D); however, the results of various experimental studies do not support this notion. To address this discrepancy, we assessed the short- and long-term effects of hypomagnesemia on β-cell function and insulin secretion in primary mouse islets of Langerhans and in a mouse model of hypomagnesemia known as Trpm6Δ17 /fl;Villin1-Cre mice. We found that lowering the extracellular Mg2+ concentration from 1.2 mM to either 0.6 or 0.1 mM remarkably increased glucose-induced insulin secretion (GIIS) in primary islets isolated from C57BL/6 mice. Similarly, both the plasma insulin levels and GIIS rose in isolated islets of Trpm6Δ17 /fl;Villin1-Cre mice. We attribute these rises to augmented increases in intracellular Ca2+ oscillations in pancreatic β-cells. However, the glycemic metabolic profile was not impaired in Trpm6Δ17 /fl;Villin1-Cre mice, suggesting that chronic hypomagnesemia does not lead to insulin resistance. Collectively, the results of this study suggest that neither acute nor chronic Mg2+ deficiency suppresses glucose-induced rises in insulin secretion. Even though hypomagnesemia can be symptomatic of T2D, such deficiency may not account for declines in insulin release in this disease.
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Affiliation(s)
- Noushafarin Khajavi
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
| | - Klea Riçku
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
| | - Pascale C. F. Schreier
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
| | - Tanja Gentz
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
| | - Philipp Beyerle
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
| | - Emmanuel Cruz
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
| | - Andreas Breit
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
| | - Peter S. Reinach
- Ophthalmology Department, Wenzhou Medical University, Wenzhou 325015, China;
| | - Thomas Gudermann
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
- German Center for Lung Research, 81377 Munich, Germany
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3
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Shatynska O, Tokarskyy O, Lykhatskyi P, Yaremchuk O, Bandas I, Mashtalir A. Dietary supplementation with magnesium citrate may improve pancreatic metabolic indices in an alloxan-induced diabetes rat model. POTRAVINARSTVO 2020. [DOI: 10.5219/1375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The purpose of the current study was to evaluate the protective properties of dietary magnesium supplementation on pancreatic tissue of rats with alloxan-induced diabetes mellitus. Twenty-five male Wistar rats were split into five groups (control, diabetes, diabetes with 100 mg Mg daily, diabetes with 250 mg Mg daily, diabetes with 500 mg Mg daily) with feeding supplementation starting on day 1, diabetes induction on day 21, and animal sacrifice on day 30. Fasting glucose in blood serum was measured on days 21, 25, 27, and day 30. Glucose metabolism enzymes, namely, lactate dehydrogenase and glucose-6-phosphate dehydrogenase, were measured in pancreatic tissue upon the sacrifice, as well as lipid peroxidation, antioxidant system protective enzymes (catalase and superoxide dismutase), and glutathione system components (glutathione reductase, glutathione peroxidase, and glutathione reduced). Pearson correlation coefficients showed strong negative correlation between serum glucose (control and diabetic animals) and glucose metabolism enzymes, catalase, superoxide dismutase, glutathione peroxidase in pancreatic tissue (r >-0.9, p <0.05), moderate negative correlation with reduced glutathione (r = -0.79, p <0.05), moderate positive correlation with lipid peroxidation index (r = +0.67, p <0.05), weak correlation with glutathione reductase (r = -0.57, p <0.05). Magnesium supplementation slowed down diabetes onset considering fasting glucose levels in rats (p <0.05), as well as partially restored investigated dehydrogenase levels in the pancreas of rats comparing to diabetes group (p <0.05). The lipid peroxidation index varied between treatments showing the dose-dependent influence of Mg2+. Magnesium supplementation partially restored catalase and superoxide dismutase activities in pancreatic tissue, as well as glutathione peroxidase and reduced glutathione levels (p <0.05), while glutathione reductase levels remained unaffected (p >0.05). The obtained results suggested a model, where magnesium ions may have a possible protective effect on pancreatic tissue against the negative influence of alloxan inside β cells of the pancreas.
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Cho J, Horikawa Y, Enya M, Takeda J, Imai Y, Imai Y, Handa H, Imai T. L-Arginine prevents cereblon-mediated ubiquitination of glucokinase and stimulates glucose-6-phosphate production in pancreatic β-cells. Commun Biol 2020; 3:497. [PMID: 32901087 PMCID: PMC7479149 DOI: 10.1038/s42003-020-01226-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 08/13/2020] [Indexed: 12/23/2022] Open
Abstract
We sought to determine a mechanism by which L-arginine increases glucose-stimulated insulin secretion (GSIS) in β-cells by finding a protein with affinity to L-arginine using arginine-immobilized magnetic nanobeads technology. Glucokinase (GCK), the key regulator of GSIS and a disease-causing gene of maturity-onset diabetes of the young type 2 (MODY2), was found to bind L-arginine. L-Arginine stimulated production of glucose-6-phosphate (G6P) and induced insulin secretion. We analyzed glucokinase mutants and identified three glutamate residues that mediate binding to L-arginine. One MODY2 patient with GCKE442* demonstrated lower C-peptide-to-glucose ratio after arginine administration. In β-cell line, GCKE442* reduced L-arginine-induced insulin secretion compared with GCKWT. In addition, we elucidated that the binding of arginine protects glucokinase from degradation by E3 ubiquitin ligase cereblon mediated ubiquitination. We conclude that L-arginine induces insulin secretion by increasing G6P production by glucokinase through direct stimulation and by prevention of degradation. Using arginine-immobilized magnetic nanobeads, Cho et al. show that glucokinase, the key regulator of glucose-stimulated insulin secretion, binds L-arginine, which protects glucokinase from ubiquitination-mediated degradation while inducing insulin secretion. This study provides mechanistic insights into how L-arginine increases insulin production.
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Affiliation(s)
- Jaeyong Cho
- Department Aging Intervention, National Center for Geriatrics and Gerontology, Obu, Aichi, 474-8511, Japan
| | - Yukio Horikawa
- Department of Diabetes and Endocrinology, Gifu University, Gifu, Gifu, 501-1194, Japan
| | - Mayumi Enya
- Department of Diabetes and Endocrinology, Gifu University, Gifu, Gifu, 501-1194, Japan
| | - Jun Takeda
- Department of Diabetes and Endocrinology, Gifu University, Gifu, Gifu, 501-1194, Japan
| | - Yoichi Imai
- Department of Hematology/Oncology, Research Hospital, Institute of Medical Science, University of Tokyo, Tokyo, 108-8639, Japan
| | - Yumi Imai
- Department of Internal Medicine, Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, USA
| | - Hiroshi Handa
- Department of Nanoparticle Translational Research, Tokyo Medical University, Shinjyuku, Tokyo, 160-8402, Japan
| | - Takeshi Imai
- Department Aging Intervention, National Center for Geriatrics and Gerontology, Obu, Aichi, 474-8511, Japan.
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5
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Muñoz‐Bacasehua C, Rosas‐Rodríguez JA, Arvizu‐Flores AA, Stephens‐Camacho A, Soñanez‐Organis JG, Figueroa‐Soto CG, Valenzuela‐Soto EM. Heterogeneity of active sites in recombinant betaine aldehyde dehydrogenase is modulated by potassium. J Mol Recognit 2020; 33:e2869. [DOI: 10.1002/jmr.2869] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 05/08/2020] [Accepted: 05/28/2020] [Indexed: 01/26/2023]
Affiliation(s)
- César Muñoz‐Bacasehua
- Ciencia de los AlimentosCentro de Investigación en Alimentación y Desarrollo A.C. Hermosillo México
| | - Jesús A. Rosas‐Rodríguez
- Departamento de Ciencias Químico Biológicas y AgropecuariasUniversidad de Sonora Unidad Regional Sur Navojoa México
| | | | - Aurora Stephens‐Camacho
- Licenciatura en Nutrición HumanaUniversidad Estatal de Sonora UAN, Periférico Sur y Carretera a Huatabampo Navojoa México
| | - José G. Soñanez‐Organis
- Departamento de Ciencias Químico Biológicas y AgropecuariasUniversidad de Sonora Unidad Regional Sur Navojoa México
| | - Ciria G. Figueroa‐Soto
- Ciencia de los AlimentosCentro de Investigación en Alimentación y Desarrollo A.C. Hermosillo México
| | - Elisa M. Valenzuela‐Soto
- Ciencia de los AlimentosCentro de Investigación en Alimentación y Desarrollo A.C. Hermosillo México
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Dardashti RN, Kumar S, Sternisha SM, Reddy PS, Miller BG, Metanis N. Selenolysine: A New Tool for Traceless Isopeptide Bond Formation. Chemistry 2020; 26:4952-4957. [PMID: 31960982 PMCID: PMC7184786 DOI: 10.1002/chem.202000310] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Indexed: 01/14/2023]
Abstract
Despite their biological importance, post-translationally modified proteins are notoriously difficult to produce in a homogeneous fashion by using conventional expression systems. Chemical protein synthesis or semisynthesis offers a solution to this problem; however, traditional strategies often rely on sulfur-based chemistry that is incompatible with the presence of any cysteine residues in the target protein. To overcome these limitations, we present the design and synthesis of γ-selenolysine, a selenol-containing form of the commonly modified proteinogenic amino acid, lysine. The utility of γ-selenolysine is demonstrated with the traceless ligation of the small ubiquitin-like modifier protein, SUMO-1, to a peptide segment of human glucokinase. The resulting polypeptide is poised for native chemical ligation and chemoselective deselenization in the presence of unprotected cysteine residues. Selenolysine's straightforward synthesis and incorporation into synthetic peptides marks it as a universal handle for conjugating any ubiquitin-like modifying protein to its target.
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Affiliation(s)
- Rebecca Notis Dardashti
- The Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, 91904, Israel
| | - Shailesh Kumar
- The Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, 91904, Israel
| | - Shawn M Sternisha
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, 32306-4390, USA
| | - Post Sai Reddy
- The Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, 91904, Israel
| | - Brian G Miller
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, 32306-4390, USA
| | - Norman Metanis
- The Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, 91904, Israel
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7
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Muñoz-Bacasehua C, Rosas-Rodríguez JA, Arvizu-Flores AA, Valenzuela-Soto EM. Role of potassium levels in pkBADH heterogeneity of NAD + binding site. J Bioenerg Biomembr 2020; 52:61-70. [PMID: 32128683 DOI: 10.1007/s10863-020-09827-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 02/26/2020] [Indexed: 12/20/2022]
Abstract
Betaine aldehyde dehydrogenase (BADH) catalyzes the oxidation of betaine aldehyde to glycine betaine using NAD+ as a coenzyme. Studies in porcine kidney BADH (pkBADH) suggested that the enzyme exhibits heterogeneity of active sites and undergoes potassium-induced conformational changes. This study aimed to analyze if potassium concentration plays a role in the heterogeneity of pkBADH active sites through changes in NAD+ affinity constants, in its secondary structure content and stability. The enzyme was titrated with NAD+ 1 mM at fixed-variable KCl concentration, and the interaction measured by Isothermal Titration Calorimetry (ITC) and Circular Dichroism (CD). ITC data showed that K+ increased the first active site affinity in a manner dependent on its concentration; KD values to the first site were 14.4, 13.1, and 10.4 μM, at 25, 50, and 75 mM KCl. ΔG values showed that the coenzyme binding is a spontaneous reaction without changes between active sites or depending on KCl concentration. ΔH and TΔSb values showed that NAD+ binding to the active site is an endothermic process and is carried out at the expense of changes in entropy. α-Helix content increased as KCl increased, enzyme (Tm)app values were 2.6 °C and 3.3 °C higher at 20 mM and 200 mM K+. PkBADH molecular model showed three different interaction K+ sites. Results suggested K+ can interact with pkBADH and cause changes in the secondary structure, it provokes changes in the enzyme affinity by the coenzyme, and in the thermostability.
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Affiliation(s)
- César Muñoz-Bacasehua
- Centro de Investigación en Alimentación y Desarrollo A.C, GE Astiazaran Rosas 46, 83304, Hermosillo, Sonora, Mexico
| | | | - Aldo A Arvizu-Flores
- Departamento de Ciencias Químico-Biológicas, Universidad de Sonora, Apartado Postal, 83000, Hermosillo, Sonora, Mexico
| | - Elisa M Valenzuela-Soto
- Centro de Investigación en Alimentación y Desarrollo A.C, GE Astiazaran Rosas 46, 83304, Hermosillo, Sonora, Mexico.
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8
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Šimčíková D, Kocková L, Vackářová K, Těšínský M, Heneberg P. Evidence-based tailoring of bioinformatics approaches to optimize methods that predict the effects of nonsynonymous amino acid substitutions in glucokinase. Sci Rep 2017; 7:9499. [PMID: 28842611 PMCID: PMC5573313 DOI: 10.1038/s41598-017-09810-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 07/28/2017] [Indexed: 11/29/2022] Open
Abstract
Computational methods that allow predicting the effects of nonsynonymous substitutions are an integral part of exome studies. Here, we validated and improved their specificity by performing a comprehensive bioinformatics analysis combined with experimental and clinical data on a model of glucokinase (GCK): 8835 putative variations, including 515 disease-associated variations from 1596 families with diagnoses of monogenic diabetes (GCK-MODY) or persistent hyperinsulinemic hypoglycemia of infancy (PHHI), and 126 variations with available or newly reported (19 variations) data on enzyme kinetics. We also proved that high frequency of disease-associated variations found in patients is closely related to their evolutionary conservation. The default set prediction methods predicted correctly the effects of only a part of the GCK-MODY-associated variations and completely failed to predict the normoglycemic or PHHI-associated variations. Therefore, we calculated evidence-based thresholds that improved significantly the specificity of predictions (≤75%). The combined prediction analysis even allowed to distinguish activating from inactivating variations and identified a group of putatively highly pathogenic variations (EVmutation score <−7.5 and SNAP2 score >70), which were surprisingly underrepresented among MODY patients and thus under negative selection during molecular evolution. We suggested and validated the first robust evidence-based thresholds, which allow improved, highly specific predictions of disease-associated GCK variations.
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Affiliation(s)
- Daniela Šimčíková
- Charles University, Third Faculty of Medicine, Prague, Czech Republic
| | - Lucie Kocková
- Charles University, Third Faculty of Medicine, Prague, Czech Republic
| | | | - Miroslav Těšínský
- Charles University, Third Faculty of Medicine, Prague, Czech Republic
| | - Petr Heneberg
- Charles University, Third Faculty of Medicine, Prague, Czech Republic.
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Xu H, Sheng L, Chen W, Yuan F, Yang M, Li H, Li X, Choi J, Zhao G, Hu T, Li Y, Zhang Y, Chen L. Safety, tolerability, pharmacokinetics, and pharmacodynamics of novel glucokinase activator HMS5552: results from a first-in-human single ascending dose study. DRUG DESIGN DEVELOPMENT AND THERAPY 2016; 10:1619-26. [PMID: 27274195 PMCID: PMC4869670 DOI: 10.2147/dddt.s105021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Background HMS5552, a novel fourth-generation glucokinase (GK) activator, has demonstrated promising effects on glycemic control in preclinical models of type 2 diabetes. This single ascending dose study was conducted to investigate the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of HMS5552 during its first-in-human exposure. Methods Sixty healthy subjects were enrolled. In each of six dose-cohorts (5, 10, 15, 25, 35, and 50 mg), ten subjects were randomized with eight subjects receiving the same cohort-dose of HMS5552 and two receiving placebo. Plasma HMS5552 exposure, glucose, and insulin were measured repeatedly during fasting and after a standardized meal. Assessment included safety, PK, and PD endpoints. Results HMS5552 showed dose-proportional increases in area under the curve 0 to the last quantifiable concentration (AUC0–t) and maximum plasma concentration (Cmax). Slopes estimated by linear regression for AUC0–t and Cmax were ~1.0 (0.932 and 0.933, respectively). Geometric mean elimination half-life ranged from 4.48 to 7.51 hours and apparent clearance ranged from 11.5 to 13.1 L/h across all doses. No significant sex effect was observed in PK parameters. HMS5552 also demonstrated dose-related PD responses in terms of maximum glucose change from baseline (%) and mean glucose area under effect curve 0–4 hours change from baseline (%) (P<0.001). Fifteen adverse events were reported by nine subjects (ten with HMS5552 and five with the placebo). All adverse events were mild in intensity and resolved without any treatment. Conclusion This first-in-human single ascending dose study provided predicted PK of HMS5552 with dose-proportional increases in AUC0–t and Cmax, as well as dose-related glucose-lowering effects over the range of 5–50 mg in healthy subjects. HMS5552 at doses up to 50 mg in healthy subjects was safe and well-tolerated.
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Affiliation(s)
- Hongrong Xu
- Department of Clinical Pharmacology, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Lei Sheng
- Department of Clinical Pharmacology, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Weili Chen
- Department of Clinical Pharmacology, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Fei Yuan
- Department of Clinical Pharmacology, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Mengjie Yang
- Department of Clinical Pharmacology, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Hui Li
- Department of Clinical Pharmacology, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Xuening Li
- Department of Clinical Pharmacology, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China
| | - John Choi
- Department of Clinical Research & Development, Hua Medicine, Shanghai, People's Republic of China
| | - Guiyu Zhao
- Department of Clinical Research & Development, Hua Medicine, Shanghai, People's Republic of China
| | - Tianxin Hu
- Department of Clinical Research & Development, Hua Medicine, Shanghai, People's Republic of China
| | - Yongguo Li
- Department of Clinical Research & Development, Hua Medicine, Shanghai, People's Republic of China
| | - Yi Zhang
- Department of Clinical Research & Development, Hua Medicine, Shanghai, People's Republic of China
| | - Li Chen
- Department of Clinical Research & Development, Hua Medicine, Shanghai, People's Republic of China
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10
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Abstract
Over the past decades, hypomagnesemia (serum Mg(2+) <0.7 mmol/L) has been strongly associated with type 2 diabetes mellitus (T2DM). Patients with hypomagnesemia show a more rapid disease progression and have an increased risk for diabetes complications. Clinical studies demonstrate that T2DM patients with hypomagnesemia have reduced pancreatic β-cell activity and are more insulin resistant. Moreover, dietary Mg(2+) supplementation for patients with T2DM improves glucose metabolism and insulin sensitivity. Intracellular Mg(2+) regulates glucokinase, KATP channels, and L-type Ca(2+) channels in pancreatic β-cells, preceding insulin secretion. Moreover, insulin receptor autophosphorylation is dependent on intracellular Mg(2+) concentrations, making Mg(2+) a direct factor in the development of insulin resistance. Conversely, insulin is an important regulator of Mg(2+) homeostasis. In the kidney, insulin activates the renal Mg(2+) channel transient receptor potential melastatin type 6 that determines the final urinary Mg(2+) excretion. Consequently, patients with T2DM and hypomagnesemia enter a vicious circle in which hypomagnesemia causes insulin resistance and insulin resistance reduces serum Mg(2+) concentrations. This Perspective provides a systematic overview of the molecular mechanisms underlying the effects of Mg(2+) on insulin secretion and insulin signaling. In addition to providing a review of current knowledge, we provide novel directions for future research and identify previously neglected contributors to hypomagnesemia in T2DM.
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Affiliation(s)
- Lisanne M M Gommers
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, U.K.
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11
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Negahdar M, Aukrust I, Molnes J, Solheim MH, Johansson BB, Sagen JV, Dahl-Jørgensen K, Kulkarni RN, Søvik O, Flatmark T, Njølstad PR, Bjørkhaug L. GCK-MODY diabetes as a protein misfolding disease: the mutation R275C promotes protein misfolding, self-association and cellular degradation. Mol Cell Endocrinol 2014; 382:55-65. [PMID: 24001579 DOI: 10.1016/j.mce.2013.08.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 08/22/2013] [Accepted: 08/23/2013] [Indexed: 11/28/2022]
Abstract
GCK-MODY, dominantly inherited mild hyperglycemia, is associated with more than 600 mutations in the glucokinase gene. Different molecular mechanisms have been shown to explain GCK-MODY. Here, we report a Pakistani family harboring the glucokinase mutation c.823C>T (p.R275C). The recombinant and in cellulo expressed mutant pancreatic enzyme revealed slightly increased enzyme activity (kcat) and normal affinity for α-D-glucose, and resistance to limited proteolysis by trypsin comparable with wild-type. When stably expressed in HEK293 cells and MIN6 β-cells (at different levels), the mutant protein appeared misfolded and unstable with a propensity to form dimers and aggregates. Its degradation rate was increased, involving the lysosomal and proteasomal quality control systems. On mutation, a hydrogen bond between the R275 side-chain and the carbonyl oxygen of D267 is broken, destabilizing the F260-L271 loop structure and the protein. This promotes the formation of dimers/aggregates and suggests that an increased cellular degradation is the molecular mechanism by which R275C causes GCK-MODY.
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Affiliation(s)
- Maria Negahdar
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Ingvild Aukrust
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway; Section of Islet Cell Biology and Regenerative Medicine, Joslin Diabetes Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Janne Molnes
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway; Department of Pediatrics, Haukeland University Hospital, Bergen, Norway
| | - Marie H Solheim
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Bente B Johansson
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway; Department of Pediatrics, Haukeland University Hospital, Bergen, Norway
| | - Jørn V Sagen
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Institute of Medicine, University of Bergen, Bergen, Norway; Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
| | - Knut Dahl-Jørgensen
- Pediatric Department Ullevaal, Oslo University Hospital, Oslo, Norway; Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Rohit N Kulkarni
- Section of Islet Cell Biology and Regenerative Medicine, Joslin Diabetes Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Oddmund Søvik
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway
| | | | - Pål R Njølstad
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Department of Pediatrics, Haukeland University Hospital, Bergen, Norway.
| | - Lise Bjørkhaug
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway
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12
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Shammas C, Neocleous V, Phelan MM, Lian LY, Skordis N, Phylactou LA. A report of 2 new cases of MODY2 and review of the literature: implications in the search for type 2 diabetes drugs. Metabolism 2013; 62:1535-42. [PMID: 23890519 DOI: 10.1016/j.metabol.2013.06.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 06/11/2013] [Accepted: 06/11/2013] [Indexed: 10/26/2022]
Abstract
Glucokinase (GCK) acts as a glucose sensor and stimulates the release of insulin from pancreatic β-cells and any GCK gene mutations can lead to different forms of diabetes, such as GCK-monogenic diabetes of the young type 2 (MODY2), permanent neonatal diabetes and congenital hyperinsulinism. Many MODY2 causing mutations display a variation in the degree of severity, ranging from mild dietary-restricted forms to more detrimental presentation requiring insulin replacement. The present study reviews known and two novel GCK mutations in terms of molecular perturbation of the GCK atomic structure but also emphasizes the inactivating and activating properties of the GCK as treatment for T2DM. In silico analysis demonstrated that the newly discovered mutation p.Arg447Pro causes structural conformational changes that lead to the destabilization of the functional properties of the protein resulting in the reduction of glucose and MgATP2- affinity. The novel p.Glu440Stop nonsense mutation on the other hand inactivates the cytoplasmic enzymatic activity of the protein as it is responsible for the loss of the C-terminal end of the polypeptide that includes vital glucose-releasing residues. Based on the in silico models of existing structural data we identified several classes of GCK mutations and discuss their relation to disease outcome. GCK has a central role in controlling body glucose homeostasis and therefore is considered an outstanding drug target for developing new antidiabetic therapies using small molecular activators (GKAs). This study emphasizes the importance in understanding how inactivating and activating GCK mutations affect the mechanistic properties of this glucose sensor. Such information can become the basis for drug discovery of therapeutic compounds and the treatment of T2DM by targeting the GCK allosteric activator site.
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Affiliation(s)
- Christos Shammas
- Department of Molecular Genetics, Function and Therapy, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
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13
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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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14
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Zelent B, Buettger C, Grimsby J, Sarabu R, Vanderkooi JM, Wand AJ, Matschinsky FM. Thermal stability of glucokinase (GK) as influenced by the substrate glucose, an allosteric glucokinase activator drug (GKA) and the osmolytes glycerol and urea. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:769-84. [PMID: 22446163 DOI: 10.1016/j.bbapap.2012.03.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 02/15/2012] [Accepted: 03/05/2012] [Indexed: 11/27/2022]
Abstract
We investigated how glycerol, urea, glucose and a GKA influence kinetics and stability of wild-type and mutant GK. Glycerol and glucose stabilized GK additively. Glycerol barely affected the TF spectra of all GKs but decreased k(cat), glucose S(0.5) and K(D) values and ATP K(M) while leaving cooperativity unchanged. Glycerol sensitized all GKs to GKA as shown by TF. Glucose increased TF of GKs without influence of glycerol on the effect. Glycerol and GKA affected kinetics and binding additively. The activation energies for thermal denaturation of GK were a function of glucose with K(D)s of 3 and 1mM without and with glycerol, respectively. High urea denatured wild type GK reversibly at 20 and 60°C and urea treatment of irreversibly heat denatured GK allowed refolding as demonstrated by TF including glucose response. We concluded: Glycerol stabilizes GK indirectly without changing the folding structure of the apoenzyme, by restructuring the surface water of the protein, whereas glucose stabilizes GK directly by binding to its substrate site and inducing a compact conformation. Glucose or glycerol (alone or combined) is unable to prevent irreversible heat denaturation above 40°C. However, urea denatures GK reversibly even at 60°C by binding to the protein backbone and directly interacting with hydrophobic side chains. It prevents irreversible aggregation allowing complete refolding when urea is removed. This study establishes the foundation for exploring numerous instability mutants among the more than 600 variant GKs causing diabetes in animals and humans.
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Affiliation(s)
- B Zelent
- Department of Biochemistry and Biophysics and Diabetes Research Center, University of Pennsylvania, Philadelphia, PA 19104, USA
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15
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Liu S, Ammirati MJ, Song X, Knafels JD, Zhang J, Greasley SE, Pfefferkorn JA, Qiu X. Insights into mechanism of glucokinase activation: observation of multiple distinct protein conformations. J Biol Chem 2012; 287:13598-610. [PMID: 22298776 DOI: 10.1074/jbc.m111.274126] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Human glucokinase (GK) is a principal regulating sensor of plasma glucose levels. Mutations that inactivate GK are linked to diabetes, and mutations that activate it are associated with hypoglycemia. Unique kinetic properties equip GK for its regulatory role: although it has weak basal affinity for glucose, positive cooperativity in its binding of glucose causes a rapid increase in catalytic activity when plasma glucose concentrations rise above euglycemic levels. In clinical trials, small molecule GK activators (GKAs) have been efficacious in lowering plasma glucose and enhancing glucose-stimulated insulin secretion, but they carry a risk of overly activating GK and causing hypoglycemia. The theoretical models proposed to date attribute the positive cooperativity of GK to the existence of distinct protein conformations that interconvert slowly and exhibit different affinities for glucose. Here we report the respective crystal structures of the catalytic complex of GK and of a GK-glucose complex in a wide open conformation. To assess conformations of GK in solution, we also carried out small angle x-ray scattering experiments. The results showed that glucose dose-dependently converts GK from an apo conformation to an active open conformation. Compared with wild type GK, activating mutants required notably lower concentrations of glucose to be converted to the active open conformation. GKAs decreased the level of glucose required for GK activation, and different compounds demonstrated distinct activation profiles. These results lead us to propose a modified mnemonic model to explain cooperativity in GK. Our findings may offer new approaches for designing GKAs with reduced hypoglycemic risk.
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Affiliation(s)
- Shenping Liu
- Structural Biology and Biophysics, Pfizer Groton Laboratories, Groton, Connecticut 06340, USA.
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16
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García-Herrero CM, Rubio-Cabezas O, Azriel S, Gutierrez-Nogués A, Aragonés A, Vincent O, Campos-Barros A, Argente J, Navas MA. Functional characterization of MODY2 mutations highlights the importance of the fine-tuning of glucokinase and its role in glucose sensing. PLoS One 2012; 7:e30518. [PMID: 22291974 PMCID: PMC3265476 DOI: 10.1371/journal.pone.0030518] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 12/17/2011] [Indexed: 11/19/2022] Open
Abstract
Glucokinase (GK) acts as a glucose sensor in the pancreatic beta-cell and regulates insulin secretion. Heterozygous mutations in the human GK-encoding GCK gene that reduce the activity index increase the glucose-stimulated insulin secretion threshold and cause familial, mild fasting hyperglycaemia, also known as Maturity Onset Diabetes of the Young type 2 (MODY2). Here we describe the biochemical characterization of five missense GK mutations: p.Ile130Thr, p.Asp205His, p.Gly223Ser, p.His416Arg and p.Ala449Thr. The enzymatic analysis of the corresponding bacterially expressed GST-GK mutant proteins show that all of them impair the kinetic characteristics of the enzyme. In keeping with their position within the protein, mutations p.Ile130Thr, p.Asp205His, p.Gly223Ser, and p.His416Arg strongly decrease the activity index of GK, affecting to one or more kinetic parameters. In contrast, the p.Ala449Thr mutation, which is located in the allosteric activator site, does not affect significantly the activity index of GK, but dramatically modifies the main kinetic parameters responsible for the function of this enzyme as a glucose sensor. The reduced Kcat of the mutant (3.21±0.28 s(-1) vs 47.86±2.78 s(-1)) is balanced by an increased glucose affinity (S(0.5) = 1.33±0.08 mM vs 7.86±0.09 mM) and loss of cooperativity for this substrate. We further studied the mechanism by which this mutation impaired GK kinetics by measuring the differential effects of several competitive inhibitors and one allosteric activator on the mutant protein. Our results suggest that this mutation alters the equilibrium between the conformational states of glucokinase and highlights the importance of the fine-tuning of GK and its role in glucose sensing.
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Affiliation(s)
- Carmen-María García-Herrero
- Departamento de Bioquímica y Biología Molecular III, Facultad de Medicina, Universidad Complutense de Madrid and Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas (CIBERDEM), www.ciberdem.net, Instituto de Salud Carlos III, Madrid, Spain
| | - Oscar Rubio-Cabezas
- Servicio de Endocrinología, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación La Princesa and Departamento de Pediatría, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición (CIBEROBN), www.ciberobn.es, Instituto de Salud Carlos III, Madrid, Spain
| | - Sharona Azriel
- Servicio de Endocrinología, Hospital Universitario Infanta Sofía, San Sebastián de los Reyes, Madrid, Spain
| | - Angel Gutierrez-Nogués
- Departamento de Bioquímica y Biología Molecular III, Facultad de Medicina, Universidad Complutense de Madrid and Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
| | - Angel Aragonés
- Servicio de Pediatría, Hospital Virgen de la Salud, Toledo, Spain
| | - Olivier Vincent
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain
| | - Angel Campos-Barros
- Servicio de Endocrinología, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación La Princesa and Departamento de Pediatría, Universidad Autónoma de Madrid, Madrid, Spain
| | - Jesús Argente
- Servicio de Endocrinología, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación La Princesa and Departamento de Pediatría, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición (CIBEROBN), www.ciberobn.es, Instituto de Salud Carlos III, Madrid, Spain
| | - María-Angeles Navas
- Departamento de Bioquímica y Biología Molecular III, Facultad de Medicina, Universidad Complutense de Madrid and Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas (CIBERDEM), www.ciberdem.net, Instituto de Salud Carlos III, Madrid, Spain
- * E-mail:
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17
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Petit P, Antoine M, Ferry G, Boutin JA, Lagarde A, Gluais L, Vincentelli R, Vuillard L. The active conformation of human glucokinase is not altered by allosteric activators. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2011; 67:929-35. [PMID: 22101819 DOI: 10.1107/s0907444911036729] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 09/09/2011] [Indexed: 11/10/2022]
Abstract
Glucokinase (GK) catalyses the formation of glucose 6-phosphate from glucose and ATP. A specific feature of GK amongst hexokinases is that it can cycle between active and inactive conformations as a function of glucose concentration, resulting in a unique positive kinetic cooperativity with glucose, which turns GK into a unique key sensor of glucose metabolism, notably in the pancreas. GK is a target of antidiabetic drugs aimed at the activation of GK activity, leading to insulin secretion. Here, the first structures of a GK-glucose complex without activator, of GK-glucose-AMP-PNP and of GK-glucose-AMP-PNP with a bound activator are reported. All these structures are extremely similar, thus demonstrating that binding of GK activators does not result in conformational changes of the active protein but in stabilization of the active form of GK.
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Affiliation(s)
- Pierre Petit
- BioXtal, PX Unit, c/o AFMB, UMR 6098, Case 932, 163 Avenue de Luminy, 13288 Marseille CEDEX 09, France
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