Esteban Quezada, Klaus-Peter Knoch, Jovana Vasiljevic, Annika Seiler, Akshaye Pal, Abishek Gunasekaran, Carla Münster, Daniela Friedland, Eyke Schöniger, Anke Sönmez, Pascal Roch, Carolin Wegbrod, Katharina Ganß, Nicole Kipke, Simon Alberti, Rita Nano, Lorenzo Piemonti, Daniela Aust, Jürgen Weitz, Marius Distler, Michele Solimena
Aldolase-regulated G3BP1/2+ condensates control insulin mRNA storage in beta cells.
EMBO J, 44(13) 3669-3696 (2025)
Open Access PubMed Source
Upregulation of insulin mRNA translation upon hyperglycemia in pancreatic islet β-cells involves several RNA-binding proteins. Here, we found that G3BP1, a stress granule marker downregulated in islets of subjects with type 2 diabetes, binds to insulin mRNA in glucose concentration-dependent manner. We show in mouse insulinoma MIN6-K8 cells exposed to fasting glucose levels that G3BP1 and its paralog G3BP2 colocalize to cytosolic condensates with eIF3b, phospho-AMPKαThr172 and Ins1/2 mRNA. Glucose stimulation dissolves G3BP1+/2+ condensates with cytosolic redistribution of their components. The aldolase inhibitor aldometanib prevents the glucose- and pyruvate-induced dissolution of G3BP1+/2+ condensates, increases phospho-AMPKαThr172 levels and reduces those of phospho-mTORSer2448. G3BP1 or G3BP2 depletion precludes condensate assembly. KO of G3BP1 decreases Ins1/2 mRNA abundance and translation as well as proinsulin levels, and impaires glucose-stimulated insulin secretion. Further, other insulin secretagogues such as exendin-4 and palmitate, but not high KCl, prompts the dissolution of G3BP1+/2+ condensates. G3BP1+/2+/Ins mRNA+ condensates are also found in primary mouse and human β-cells. Hence, G3BP1+/2+ condensates represent a conserved glycolysis/aldolase-regulated compartment for the physiological storage and protection of insulin mRNA in resting β-cells.
@article{Quezada9001,
author={Esteban Quezada, Klaus-Peter Knoch, Jovana Vasiljevic, Annika Seiler, Akshaye Pal, Abishek Gunasekaran, Carla Münster, Daniela Friedland, Eyke Schöniger, Anke Sönmez, Pascal Roch, Carolin Wegbrod, Katharina Ganß, Nicole Kipke, Simon Alberti, Rita Nano, Lorenzo Piemonti, Daniela Aust, Jürgen Weitz, Marius Distler, Michele Solimena},
title={Aldolase-regulated G3BP1/2+ condensates control insulin mRNA storage in beta cells.},
journal ={The EMBO journal},
volume={44},
issue ={13},
pages={3669--3696},
year=2025
}