Insights into the regulation of glucokinase from novel mutational mechanisms causing pancreatic beta-cell dysfunction

Lead Research Organisation: University of Oxford
Department Name: Unknown

Abstract

Glucokinase plays an important role in insulin secretion and is a current therapeutic target for diabetes. Patients with faults in the gene encoding this protein can have either diabetes or raised fasting blood glucose that is usually treated by diet alone or low blood glucose levels which are usually treated with diazoxide.

It is not understood how all of these faulty proteins result in low or high blood glucose values in patients. This study aims to investigate the mechanisms by which the defective genes cause diabetes or low blood glucose. Recently it has been discovered that some faults in genes do not cause disease because they change the protein; but that they affect the intermediate step of RNA processing that prevents or alters protein synthesis. My study will look at whether this is true for glucokinase gene defects. I will also look to see if some defects in genes cause disease because they prevent the glucokinase protein from being regulated by other proteins. This work is important because it will help interpret genetic test results and will also increase our understanding of an important drug target for the development of therapeutic agents to treat diabetes.

Technical Summary

Glucokinase plays a central role in the regulation of insulin secretion. Variation within the glucokinase (GCK) gene is causally-related to a range of phenotypes reflecting beta-cell dysfunction including monogenic diabetes (MODY), hyperinsulinaemic hypoglycaemia (HI), glucose levels and birth weight. GCK activators represent an emerging therapeutic option for type 2 diabetes.

The more than 200 GCK mutations so far implicated in monogenic conditions are widely-distributed across the gene. Molecular diagnostic testing is well-established in both MODY and HI, as identification of a GCK mutation provides information highly-relevant to the clinical management of the proband and their family.

In addition to the clinical and physiological insights, the detailed functional analysis of GCK mutations has provided important clues into the function, structure and regulation of this key enzyme. To date, GCK mutations have been shown to display a range of mutational mechanisms including kinetic inactivation (causing MODY), activation (in HI) and thermal-lability. However, my own preliminary work has identified a number of clearly-pathogenic mutations for which routine kinetic studies have failed to demonstrate a molecular basis for pathogenicity, or where kinetic studies may actually be misleading. I have also identified and characterised a large number of families segregating GCK-like MODY in whom extensive resequencing has failed to identify GCK mutations; and HI cases in whom all known genetic causes have been excluded.

A range of mutational mechanisms may be operating in these individuals: including abnormalities of RNA processing, disruptions of the interactions between GCK and regulatory/binding partners, copy number variation (CNV), and/or mutations in genes encoding regulatory partners of GCK. A detailed understanding of the molecular mechanisms involved will not only add novel clues to the regulation and function of GCK: it is also critical for appropriate clinical management.

The aims of this project are:
(i) to perform a systematic assessment of a selected group of 34 GCK-MODY mutations to identify the mutational mechanisms responsible: this will involve studies of mRNA processing, enzyme kinetics, interaction dynamics and mRNA and protein stability.
(ii) to determine the role of CNV in GCK-related phenotypes;
(iii) to investigate the role of mutations in the gene(s) encoding important islet GCK- regulatory proteins in beta-cell dysfunction.

This work should provide: (i) improved clinical diagnostics for families with monogenic diabetes and HI; (ii) insights into fundamental mechanisms of beta-cell regulation and function (relevant to all forms of diabetes); and (iii) the potential for novel, improved therapeutic tools for manipulation of beta-cell function.

Publications

10 25 50

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Gloyn AL (2008) Genetics: how the UKPDS contributed to determining the genetic landscape of Type 2 diabetes. in Diabetic medicine : a journal of the British Diabetic Association

 
Description Diabetes UK Studentship
Amount £72,000 (GBP)
Organisation Diabetes UK 
Sector Charity/Non Profit
Country United Kingdom
Start 10/2010 
End 09/2013
 
Description Diabetes UK, Clinical Training Fellowship
Amount £124,571 (GBP)
Organisation Diabetes UK 
Sector Charity/Non Profit
Country United Kingdom
Start 06/2008 
End 09/2010
 
Description MRC Clinical Training Fellowship
Amount £212,076 (GBP)
Organisation Medical Research Council (MRC) 
Sector Public
Country United Kingdom
Start 09/2008 
End 09/2011
 
Description Wellcome Trust Senior Fellowship in Basic Biomedical Research
Amount £1,500,000 (GBP)
Organisation Wellcome Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 07/2011 
End 06/2016
 
Title Glucokinase mutation update 
Description We have published a mutation update (Osbak et al Human Mutation 2009) which details >600 naturally occurring glucokinase mutations which cause human disease. In addition to the database of mutations a comprehensive list of non-pathogenic genetic variation has also been compiled. 
Type Of Material Database/Collection of Data/Biological Samples 
Year Produced 2009 
Provided To Others? Yes  
Impact This database of mutations provides an important tool for laboratories offering genetic diagnostic testing for glucokinase glycaemic disorders. 
 
Description CEED3 (Collaborative European Effort to Develop Diabetes Diagnostics) 
Organisation August Pi i Sunyer Biomedical Research Institute
Department Hospital Clinic of Barcelona
Country Spain 
Sector Hospitals 
PI Contribution I am involved in the Biomarker discovery for monogenic diabetes.
Collaborator Contribution This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage.
Impact My senior author paper published in Diabetes Care (PubMed 20724646) partly resulted through this initative. This study has shown for the first time that CRP is a potential biomarker which can be used to prioritise patients for genetic testing for HNF1A-MODY. This is a mutli-disciplinary collaboration with basic scientists, clinicians.
Start Year 2008
 
Description CEED3 (Collaborative European Effort to Develop Diabetes Diagnostics) 
Organisation ETH Zurich
Department Institute of Molecular Systems Biology
Country Switzerland 
Sector Academic/University 
PI Contribution I am involved in the Biomarker discovery for monogenic diabetes.
Collaborator Contribution This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage.
Impact My senior author paper published in Diabetes Care (PubMed 20724646) partly resulted through this initative. This study has shown for the first time that CRP is a potential biomarker which can be used to prioritise patients for genetic testing for HNF1A-MODY. This is a mutli-disciplinary collaboration with basic scientists, clinicians.
Start Year 2008
 
Description CEED3 (Collaborative European Effort to Develop Diabetes Diagnostics) 
Organisation Free University of Brussels
Country Belgium 
Sector Academic/University 
PI Contribution I am involved in the Biomarker discovery for monogenic diabetes.
Collaborator Contribution This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage.
Impact My senior author paper published in Diabetes Care (PubMed 20724646) partly resulted through this initative. This study has shown for the first time that CRP is a potential biomarker which can be used to prioritise patients for genetic testing for HNF1A-MODY. This is a mutli-disciplinary collaboration with basic scientists, clinicians.
Start Year 2008
 
Description CEED3 (Collaborative European Effort to Develop Diabetes Diagnostics) 
Organisation IntegraGen
Country France 
Sector Private 
PI Contribution I am involved in the Biomarker discovery for monogenic diabetes.
Collaborator Contribution This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage.
Impact My senior author paper published in Diabetes Care (PubMed 20724646) partly resulted through this initative. This study has shown for the first time that CRP is a potential biomarker which can be used to prioritise patients for genetic testing for HNF1A-MODY. This is a mutli-disciplinary collaboration with basic scientists, clinicians.
Start Year 2008
 
Description CEED3 (Collaborative European Effort to Develop Diabetes Diagnostics) 
Organisation Jagiellonian University
Country Poland 
Sector Academic/University 
PI Contribution I am involved in the Biomarker discovery for monogenic diabetes.
Collaborator Contribution This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage.
Impact My senior author paper published in Diabetes Care (PubMed 20724646) partly resulted through this initative. This study has shown for the first time that CRP is a potential biomarker which can be used to prioritise patients for genetic testing for HNF1A-MODY. This is a mutli-disciplinary collaboration with basic scientists, clinicians.
Start Year 2008
 
Description CEED3 (Collaborative European Effort to Develop Diabetes Diagnostics) 
Organisation Lund University
Country Sweden 
Sector Academic/University 
PI Contribution I am involved in the Biomarker discovery for monogenic diabetes.
Collaborator Contribution This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage.
Impact My senior author paper published in Diabetes Care (PubMed 20724646) partly resulted through this initative. This study has shown for the first time that CRP is a potential biomarker which can be used to prioritise patients for genetic testing for HNF1A-MODY. This is a mutli-disciplinary collaboration with basic scientists, clinicians.
Start Year 2008
 
Description CEED3 (Collaborative European Effort to Develop Diabetes Diagnostics) 
Organisation Peninsula College of Medicine & Dentistry
Country United Kingdom 
Sector Academic/University 
PI Contribution I am involved in the Biomarker discovery for monogenic diabetes.
Collaborator Contribution This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage.
Impact My senior author paper published in Diabetes Care (PubMed 20724646) partly resulted through this initative. This study has shown for the first time that CRP is a potential biomarker which can be used to prioritise patients for genetic testing for HNF1A-MODY. This is a mutli-disciplinary collaboration with basic scientists, clinicians.
Start Year 2008
 
Description CEED3 (Collaborative European Effort to Develop Diabetes Diagnostics) 
Organisation Proteomika
Country Spain 
Sector Private 
PI Contribution I am involved in the Biomarker discovery for monogenic diabetes.
Collaborator Contribution This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage.
Impact My senior author paper published in Diabetes Care (PubMed 20724646) partly resulted through this initative. This study has shown for the first time that CRP is a potential biomarker which can be used to prioritise patients for genetic testing for HNF1A-MODY. This is a mutli-disciplinary collaboration with basic scientists, clinicians.
Start Year 2008
 
Description CEED3 (Collaborative European Effort to Develop Diabetes Diagnostics) 
Organisation Technical University of Dresden
Country Germany 
Sector Academic/University 
PI Contribution I am involved in the Biomarker discovery for monogenic diabetes.
Collaborator Contribution This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage.
Impact My senior author paper published in Diabetes Care (PubMed 20724646) partly resulted through this initative. This study has shown for the first time that CRP is a potential biomarker which can be used to prioritise patients for genetic testing for HNF1A-MODY. This is a mutli-disciplinary collaboration with basic scientists, clinicians.
Start Year 2008
 
Description CEED3 (Collaborative European Effort to Develop Diabetes Diagnostics) 
Organisation University of Helsinki
Country Finland 
Sector Academic/University 
PI Contribution I am involved in the Biomarker discovery for monogenic diabetes.
Collaborator Contribution This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage. This grant has only been running for one month so hard to assess the contributions at this stage.
Impact My senior author paper published in Diabetes Care (PubMed 20724646) partly resulted through this initative. This study has shown for the first time that CRP is a potential biomarker which can be used to prioritise patients for genetic testing for HNF1A-MODY. This is a mutli-disciplinary collaboration with basic scientists, clinicians.
Start Year 2008
 
Description Functional studies on genetic variants of glucokinase regulatory protein 
Organisation Broad Institute
Country United States 
Sector Charity/Non Profit 
PI Contribution I have set up a research collaboration on glucokinase regulatory protein with Dr Francis Collins (NIH, Bethesda, USA), Dr Marjo Orho-Melander (Lund University, Sweden) and Dr David Altshuler (Broad Institute of Harvard and MIT, Boston, USA). This collaboration now involves a joint student (Matthew Rees) with Prof Francis Collins (NIH) who is funded by the NIH/Oxbridge system. Matt is spending half his time in my laboratory working on the kinetic characterisation of rare genetic variants in glucokinase regulatory protein GCKR). Matt is working closely with my MRC funded PhD student Nicola Beer who also works on glucokinase regulatory protein (Beer et al Human Molecular Genetics 2009; 19643913 ). My lab has hosted a PhD student (Charlotta Roos) from Dr Orho-Melander's group for a 3 month visit to work on GKRP. This was funded by an European Foundation for the Study of Diabetes (EFSD) travelling fellowship.
Collaborator Contribution Dr Marju Orho-Melander was involved in the identification of the P446L GCKR variant and its role in blood glucose levels in the general population. Dr Orho-Melander provided genetic information for my functional studies. Professor David Altshuler and his team at the Broad were involved in the discovery that a common genetic variant in glucokinase regulatory protein (P446L) was involved in fasting plasma glucose levels in the general population. This information was shared with me prior to publication. I have a collaboration with Francis Collins. We now have a joint PhD student (Matthew Rees) who is funded on the NIH/Oxbridge system. Matt is spending half of his time in my laboratory working on the kinetic characterisation of rare genetics variants identified in patients with abnormal glucose and lipid levels and the remaining time at NIH working on the cellular characterisation of these variants. The majority of these rare variants have been identified in the NIH Clin Seq project. My MRC funded PhD student (Nicola Beer) has visited NIH for a 3 month visit funded by the European Foundation for the Study of Diabetes (EFSD) to perform some cellular studies on the P446L glucokinase regulatory protein variant protein.
Impact Funding from NIH for Matthew Rees' 4 year PhD studentship. 19643913
Start Year 2008
 
Description Functional studies on genetic variants of glucokinase regulatory protein 
Organisation Lund University
Country Sweden 
Sector Academic/University 
PI Contribution I have set up a research collaboration on glucokinase regulatory protein with Dr Francis Collins (NIH, Bethesda, USA), Dr Marjo Orho-Melander (Lund University, Sweden) and Dr David Altshuler (Broad Institute of Harvard and MIT, Boston, USA). This collaboration now involves a joint student (Matthew Rees) with Prof Francis Collins (NIH) who is funded by the NIH/Oxbridge system. Matt is spending half his time in my laboratory working on the kinetic characterisation of rare genetic variants in glucokinase regulatory protein GCKR). Matt is working closely with my MRC funded PhD student Nicola Beer who also works on glucokinase regulatory protein (Beer et al Human Molecular Genetics 2009; 19643913 ). My lab has hosted a PhD student (Charlotta Roos) from Dr Orho-Melander's group for a 3 month visit to work on GKRP. This was funded by an European Foundation for the Study of Diabetes (EFSD) travelling fellowship.
Collaborator Contribution Dr Marju Orho-Melander was involved in the identification of the P446L GCKR variant and its role in blood glucose levels in the general population. Dr Orho-Melander provided genetic information for my functional studies. Professor David Altshuler and his team at the Broad were involved in the discovery that a common genetic variant in glucokinase regulatory protein (P446L) was involved in fasting plasma glucose levels in the general population. This information was shared with me prior to publication. I have a collaboration with Francis Collins. We now have a joint PhD student (Matthew Rees) who is funded on the NIH/Oxbridge system. Matt is spending half of his time in my laboratory working on the kinetic characterisation of rare genetics variants identified in patients with abnormal glucose and lipid levels and the remaining time at NIH working on the cellular characterisation of these variants. The majority of these rare variants have been identified in the NIH Clin Seq project. My MRC funded PhD student (Nicola Beer) has visited NIH for a 3 month visit funded by the European Foundation for the Study of Diabetes (EFSD) to perform some cellular studies on the P446L glucokinase regulatory protein variant protein.
Impact Funding from NIH for Matthew Rees' 4 year PhD studentship. 19643913
Start Year 2008
 
Description Functional studies on genetic variants of glucokinase regulatory protein 
Organisation National Institutes of Health (NIH)
Department National Human Genome Research Institute (NHGRI)
Country United States 
Sector Public 
PI Contribution I have set up a research collaboration on glucokinase regulatory protein with Dr Francis Collins (NIH, Bethesda, USA), Dr Marjo Orho-Melander (Lund University, Sweden) and Dr David Altshuler (Broad Institute of Harvard and MIT, Boston, USA). This collaboration now involves a joint student (Matthew Rees) with Prof Francis Collins (NIH) who is funded by the NIH/Oxbridge system. Matt is spending half his time in my laboratory working on the kinetic characterisation of rare genetic variants in glucokinase regulatory protein GCKR). Matt is working closely with my MRC funded PhD student Nicola Beer who also works on glucokinase regulatory protein (Beer et al Human Molecular Genetics 2009; 19643913 ). My lab has hosted a PhD student (Charlotta Roos) from Dr Orho-Melander's group for a 3 month visit to work on GKRP. This was funded by an European Foundation for the Study of Diabetes (EFSD) travelling fellowship.
Collaborator Contribution Dr Marju Orho-Melander was involved in the identification of the P446L GCKR variant and its role in blood glucose levels in the general population. Dr Orho-Melander provided genetic information for my functional studies. Professor David Altshuler and his team at the Broad were involved in the discovery that a common genetic variant in glucokinase regulatory protein (P446L) was involved in fasting plasma glucose levels in the general population. This information was shared with me prior to publication. I have a collaboration with Francis Collins. We now have a joint PhD student (Matthew Rees) who is funded on the NIH/Oxbridge system. Matt is spending half of his time in my laboratory working on the kinetic characterisation of rare genetics variants identified in patients with abnormal glucose and lipid levels and the remaining time at NIH working on the cellular characterisation of these variants. The majority of these rare variants have been identified in the NIH Clin Seq project. My MRC funded PhD student (Nicola Beer) has visited NIH for a 3 month visit funded by the European Foundation for the Study of Diabetes (EFSD) to perform some cellular studies on the P446L glucokinase regulatory protein variant protein.
Impact Funding from NIH for Matthew Rees' 4 year PhD studentship. 19643913
Start Year 2008
 
Description Diabetes UK Voluntary Group 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Primary Audience Participants in your research and patient groups
Results and Impact Approximately 30 patients with diabetes and their relatives attended a talk giving an overview of research in my group. The talk was well received and generated substantial interest in our research activities.

No measurable impact reported to date.
Year(s) Of Engagement Activity 2010