A caveolin-1 dependent glucose-6-phosphatase trafficking contributes to hepatic glucose production
Objective: Deregulation of hepatic glucose production is a key driver in the pathogenesis of diabetes, but its short-term regulation is incompletely deciphered. According to textbooks, glucose is produced in the endoplasmic reticulum by glucose-6-phosphatase (G6Pase) and then exported in the blood b...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2023-04-01
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| Series: | Molecular Metabolism |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2212877823000340 |
| _version_ | 1797867636644642816 |
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| author | Amandine Gautier-Stein Julien Chilloux Maud Soty Bernard Thorens Christophe Place Carine Zitoun Adeline Duchampt Lorine Da Costa Fabienne Rajas Christophe Lamaze Gilles Mithieux |
| author_facet | Amandine Gautier-Stein Julien Chilloux Maud Soty Bernard Thorens Christophe Place Carine Zitoun Adeline Duchampt Lorine Da Costa Fabienne Rajas Christophe Lamaze Gilles Mithieux |
| author_sort | Amandine Gautier-Stein |
| collection | DOAJ |
| description | Objective: Deregulation of hepatic glucose production is a key driver in the pathogenesis of diabetes, but its short-term regulation is incompletely deciphered. According to textbooks, glucose is produced in the endoplasmic reticulum by glucose-6-phosphatase (G6Pase) and then exported in the blood by the glucose transporter GLUT2. However, in the absence of GLUT2, glucose can be produced by a cholesterol-dependent vesicular pathway, which remains to be deciphered. Interestingly, a similar mechanism relying on vesicle trafficking controls short-term G6Pase activity. We thus investigated whether Caveolin-1 (Cav1), a master regulator of cholesterol trafficking, might be the mechanistic link between glucose production by G6Pase in the ER and glucose export through a vesicular pathway. Methods: Glucose production from fasted mice lacking Cav1, GLUT2 or both proteins was measured in vitro in primary culture of hepatocytes and in vivo by pyruvate tolerance tests. The cellular localization of Cav1 and the catalytic unit of glucose-6-phosphatase (G6PC1) were studied by western blotting from purified membranes, immunofluorescence on primary hepatocytes and fixed liver sections and by in vivo imaging of chimeric constructs overexpressed in cell lines. G6PC1 trafficking to the plasma membrane was inhibited by a broad inhibitor of vesicular pathways or by an anchoring system retaining G6PC1 specifically to the ER membrane. Results: Hepatocyte glucose production is reduced at the step catalyzed by G6Pase in the absence of Cav1. In the absence of both GLUT2 and Cav1, gluconeogenesis is nearly abolished, indicating that these pathways can be considered as the two major pathways of de novo glucose production. Mechanistically, Cav1 colocalizes but does not interact with G6PC1 and controls its localization in the Golgi complex and at the plasma membrane. The localization of G6PC1 at the plasma membrane is correlated to glucose production. Accordingly, retaining G6PC1 in the ER reduces glucose production by hepatic cells. Conclusions: Our data evidence a pathway of glucose production that relies on Cav1-dependent trafficking of G6PC1 to the plasma membrane. This reveals a new cellular regulation of G6Pase activity that contributes to hepatic glucose production and glucose homeostasis. |
| first_indexed | 2024-04-09T23:43:19Z |
| format | Article |
| id | doaj.art-060822719bc6463b90d66b9b25ea7f50 |
| institution | Directory Open Access Journal |
| issn | 2212-8778 |
| language | English |
| last_indexed | 2024-04-09T23:43:19Z |
| publishDate | 2023-04-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Molecular Metabolism |
| spelling | doaj.art-060822719bc6463b90d66b9b25ea7f502023-03-18T04:40:58ZengElsevierMolecular Metabolism2212-87782023-04-0170101700A caveolin-1 dependent glucose-6-phosphatase trafficking contributes to hepatic glucose productionAmandine Gautier-Stein0Julien Chilloux1Maud Soty2Bernard Thorens3Christophe Place4Carine Zitoun5Adeline Duchampt6Lorine Da Costa7Fabienne Rajas8Christophe Lamaze9Gilles Mithieux10Université Claude Bernard Lyon 1, Université de Lyon, INSERM UMR-S1213, F-69374, Lyon, France; Corresponding author.Université Claude Bernard Lyon 1, Université de Lyon, INSERM UMR-S1213, F-69374, Lyon, FranceUniversité Claude Bernard Lyon 1, Université de Lyon, INSERM UMR-S1213, F-69374, Lyon, FranceCenter for Integrative Genomics, University of Lausanne, Genopode Building, 1015, Lausanne, SwitzerlandLaboratoire de Physique (UMR CNRS 5672), ENS de Lyon, Université de Lyon, F-69364, Lyon cedex 07, FranceUniversité Claude Bernard Lyon 1, Université de Lyon, INSERM UMR-S1213, F-69374, Lyon, FranceUniversité Claude Bernard Lyon 1, Université de Lyon, INSERM UMR-S1213, F-69374, Lyon, FranceUniversité Claude Bernard Lyon 1, Université de Lyon, INSERM UMR-S1213, F-69374, Lyon, FranceUniversité Claude Bernard Lyon 1, Université de Lyon, INSERM UMR-S1213, F-69374, Lyon, FranceInstitut Curie, PSL Research University, INSERM U1143, CNRS UMR 3666, Membrane Mechanics and Dynamics of Intracellular Signaling Laboratory, 75005, Paris, FranceUniversité Claude Bernard Lyon 1, Université de Lyon, INSERM UMR-S1213, F-69374, Lyon, France; Corresponding authorObjective: Deregulation of hepatic glucose production is a key driver in the pathogenesis of diabetes, but its short-term regulation is incompletely deciphered. According to textbooks, glucose is produced in the endoplasmic reticulum by glucose-6-phosphatase (G6Pase) and then exported in the blood by the glucose transporter GLUT2. However, in the absence of GLUT2, glucose can be produced by a cholesterol-dependent vesicular pathway, which remains to be deciphered. Interestingly, a similar mechanism relying on vesicle trafficking controls short-term G6Pase activity. We thus investigated whether Caveolin-1 (Cav1), a master regulator of cholesterol trafficking, might be the mechanistic link between glucose production by G6Pase in the ER and glucose export through a vesicular pathway. Methods: Glucose production from fasted mice lacking Cav1, GLUT2 or both proteins was measured in vitro in primary culture of hepatocytes and in vivo by pyruvate tolerance tests. The cellular localization of Cav1 and the catalytic unit of glucose-6-phosphatase (G6PC1) were studied by western blotting from purified membranes, immunofluorescence on primary hepatocytes and fixed liver sections and by in vivo imaging of chimeric constructs overexpressed in cell lines. G6PC1 trafficking to the plasma membrane was inhibited by a broad inhibitor of vesicular pathways or by an anchoring system retaining G6PC1 specifically to the ER membrane. Results: Hepatocyte glucose production is reduced at the step catalyzed by G6Pase in the absence of Cav1. In the absence of both GLUT2 and Cav1, gluconeogenesis is nearly abolished, indicating that these pathways can be considered as the two major pathways of de novo glucose production. Mechanistically, Cav1 colocalizes but does not interact with G6PC1 and controls its localization in the Golgi complex and at the plasma membrane. The localization of G6PC1 at the plasma membrane is correlated to glucose production. Accordingly, retaining G6PC1 in the ER reduces glucose production by hepatic cells. Conclusions: Our data evidence a pathway of glucose production that relies on Cav1-dependent trafficking of G6PC1 to the plasma membrane. This reveals a new cellular regulation of G6Pase activity that contributes to hepatic glucose production and glucose homeostasis.http://www.sciencedirect.com/science/article/pii/S2212877823000340LiverGlucose-6 phosphataseGluconeogenesisIntracellular glucose transportCaveolin 1 |
| spellingShingle | Amandine Gautier-Stein Julien Chilloux Maud Soty Bernard Thorens Christophe Place Carine Zitoun Adeline Duchampt Lorine Da Costa Fabienne Rajas Christophe Lamaze Gilles Mithieux A caveolin-1 dependent glucose-6-phosphatase trafficking contributes to hepatic glucose production Molecular Metabolism Liver Glucose-6 phosphatase Gluconeogenesis Intracellular glucose transport Caveolin 1 |
| title | A caveolin-1 dependent glucose-6-phosphatase trafficking contributes to hepatic glucose production |
| title_full | A caveolin-1 dependent glucose-6-phosphatase trafficking contributes to hepatic glucose production |
| title_fullStr | A caveolin-1 dependent glucose-6-phosphatase trafficking contributes to hepatic glucose production |
| title_full_unstemmed | A caveolin-1 dependent glucose-6-phosphatase trafficking contributes to hepatic glucose production |
| title_short | A caveolin-1 dependent glucose-6-phosphatase trafficking contributes to hepatic glucose production |
| title_sort | caveolin 1 dependent glucose 6 phosphatase trafficking contributes to hepatic glucose production |
| topic | Liver Glucose-6 phosphatase Gluconeogenesis Intracellular glucose transport Caveolin 1 |
| url | http://www.sciencedirect.com/science/article/pii/S2212877823000340 |
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