TY - JOUR

T1 - A comprehensive map of human glucokinase variant activity

AU - Gersing, Sarah

AU - Cagiada, Matteo

AU - Gebbia, Marinella

AU - Gjesing, Anette P.

AU - Coté, Atina G.

AU - Seesankar, Gireesh

AU - Li, Roujia

AU - Tabet, Daniel

AU - Weile, Jochen

AU - Stein, Amelie

AU - Gloyn, Anna L.

AU - Hansen, Torben

AU - Roth, Frederick P.

AU - Lindorff-Larsen, Kresten

AU - Hartmann-Petersen, Rasmus

N1 - Publisher Copyright: © 2023, The Author(s).

PY - 2023

Y1 - 2023

N2 - 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.

AB - 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.

KW - Deep mutational scanning

KW - Diabetes

KW - Variants of uncertain significance

U2 - 10.1186/s13059-023-02935-8

DO - 10.1186/s13059-023-02935-8

M3 - Journal article

C2 - 37101203

AN - SCOPUS:85153917631

VL - 24

JO - Genome Biology (Online Edition)

JF - Genome Biology (Online Edition)

SN - 1474-7596

IS - 1

M1 - 97

ER -