8 research outputs found

    A comprehensive map of human glucokinase variant activity

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    Abstract Background Glucokinase (GCK) regulates insulin secretion to maintain appropriate blood glucose levels. Sequence variants can alter GCK activity to cause hyperinsulinemic hypoglycemia or hyperglycemia associated with GCK-maturity-onset diabetes of the young (GCK-MODY), collectively affecting up to 10 million people worldwide. Patients with GCK-MODY are frequently misdiagnosed and treated unnecessarily. Genetic testing can prevent this but is hampered by the challenge of interpreting novel missense variants. Result Here, we exploit a multiplexed yeast complementation assay to measure both hyper- and hypoactive GCK variation, capturing 97% of all possible missense and nonsense variants. Activity scores correlate with in vitro catalytic efficiency, fasting glucose levels in carriers of GCK variants and with evolutionary conservation. Hypoactive variants are concentrated at buried positions, near the active site, and at a region of known importance for GCK conformational dynamics. Some hyperactive variants shift the conformational equilibrium towards the active state through a relative destabilization of the inactive conformation. Conclusion Our comprehensive assessment of GCK variant activity promises to facilitate variant interpretation and diagnosis, expand our mechanistic understanding of hyperactive variants, and inform development of therapeutics targeting GCK

    Additional file 1 of A comprehensive map of human glucokinase variant activity

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    Additional file 1: Fig. S1. Expression of GCK variants. Fig. S2. Co-expression of GKRP and GCK. Fig. S3. Imputed map of glucokinase variant activity. Fig. S4. Activity scores mapped onto GCK ribbon diagram. Fig. S5. Evolutionary analysis of GCK homologous sequences. Fig. S6. Correlations between evolutionary conservation and activity scores. Fig. S7. Rosetta ΔΔG heatmaps. Fig. S8. Positions predicted to shift GCK towards the closed conformation are enriched at the allosteric activator site.Please check additional files if captured correctly.Error during converting author query response. Please check the eproofing link or feedback pdf for detail
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