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  • Pyruvate Kinase Controls Signal Strength in the Insulin Secretory Pathway.

Pyruvate Kinase Controls Signal Strength in the Insulin Secretory Pathway.

Cell metabolism (2020-11-05)
Sophie L Lewandowski, Rebecca L Cardone, Hannah R Foster, Thuong Ho, Evgeniy Potapenko, Chetan Poudel, Halena R VanDeusen, Sophia M Sdao, Tiago C Alves, Xiaojian Zhao, Megan E Capozzi, Arnaldo H de Souza, Ishrat Jahan, Craig J Thomas, Craig S Nunemaker, Dawn Belt Davis, Jonathan E Campbell, Richard G Kibbey, Matthew J Merrins, Sophie L Lewandowski, Rebecca L Cardone, Hannah R Foster, Thuong Ho, Evgeniy Potapenko, Chetan Poudel, Halena R VanDeusen, Sophia M Sdao, Tiago C Alves, Xiaojian Zhao, Megan E Capozzi, Arnaldo H de Souza, Ishrat Jahan, Craig J Thomas, Craig S Nunemaker, Dawn Belt Davis, Jonathan E Campbell, Richard G Kibbey, Matthew J Merrins
ABSTRACT

Pancreatic β cells couple nutrient metabolism with appropriate insulin secretion. Here, we show that pyruvate kinase (PK), which converts ADP and phosphoenolpyruvate (PEP) into ATP and pyruvate, underlies β cell sensing of both glycolytic and mitochondrial fuels. Plasma membrane-localized PK is sufficient to close KATP channels and initiate calcium influx. Small-molecule PK activators increase the frequency of ATP/ADP and calcium oscillations and potently amplify insulin secretion. PK restricts respiration by cyclically depriving mitochondria of ADP, which accelerates PEP cycling until membrane depolarization restores ADP and oxidative phosphorylation. Our findings support a compartmentalized model of β cell metabolism in which PK locally generates the ATP/ADP required for insulin secretion. Oscillatory PK activity allows mitochondria to perform synthetic and oxidative functions without any net impact on glucose oxidation. These findings suggest a potential therapeutic route for diabetes based on PK activation that would not be predicted by the current consensus single-state model of β cell function.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone, ≥98% (TLC), powder
Sigma-Aldrich
RPMI-1640 Medium, With L-glutamine and sodium bicarbonate, liquid, sterile-filtered, suitable for cell culture
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D-Fructose 1,6-bisphosphate trisodium salt hydrate, ≥98% (TLC)
Sigma-Aldrich
Dulbecco′s Modified Eagle′s Medium, Without glucose, L-glutamine, phenol red, sodium pyruvate and sodium bicarbonate, powder, suitable for cell culture
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Oligomycin A, ≥99% (HPLC)
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mono-Methyl hydrogen succinate, 95%
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Rotenone, ≥95%
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Nimodipine
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Antimycin A from Streptomyces sp.
Supelco
Tolbutamide, analytical standard