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Klec C, Madreiter-Sokolowski CT, Stryeck S, Sachdev V, Duta-Mare M, Gottschalk B, Depaoli MR, Rost R, Hay J, Waldeck-Weiermair M, Kratky D, Madl T, Malli R, Graier WF. Glycogen Synthase Kinase 3 Beta Controls Presenilin-1-Mediated Endoplasmic Reticulum Ca²⁺ Leak Directed to Mitochondria in Pancreatic Islets and β-Cells. Cell Physiol Biochem 2019; 52:57-75. [PMID: 30790505 PMCID: PMC6459368 DOI: 10.33594/000000005] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 01/15/2019] [Indexed: 01/09/2023] Open
Abstract
Background/Aims In pancreatic β-cells, the intracellular Ca2+ homeostasis is an essential regulator of the cells’ major functions. The endoplasmic reticulum (ER) as interactive intracellular Ca2+ store balances cellular Ca2+. In this study basal ER Ca2+ homeostasis was evaluated in order to reveal potential β-cell-specificity of ER Ca2+ handling and its consequences for mitochondrial Ca2+, ATP and respiration. Methods The two pancreatic cell lines INS-1 and MIN-6, freshly isolated pancreatic islets, and the two non-pancreatic cell lines HeLA and EA.hy926 were used. Cytosolic, ER and mitochondrial Ca2+ and ATP measurements were performed using single cell fluorescence microscopy and respective (genetically-encoded) sensors/dyes. Mitochondrial respiration was monitored by respirometry. GSK3β activity was measured with ELISA. Results An atypical ER Ca2+ leak was observed exclusively in pancreatic islets and β-cells. This continuous ER Ca2+ efflux is directed to mitochondria and increases basal respiration and organellar ATP levels, is established by GSK3β-mediated phosphorylation of presenilin-1, and is prevented by either knockdown of presenilin-1 or an inhibition/knockdown of GSK3β. Expression of a presenlin-1 mutant that mimics GSK3β-mediated phosphorylation established a β-cell-like ER Ca2+ leak in HeLa and EA.hy926 cells. The ER Ca2+ loss in β-cells was compensated at steady state by Ca2+ entry that is linked to the activity of TRPC3. Conclusion Pancreatic β-cells establish a cell-specific ER Ca2+ leak that is under the control of GSK3β and directed to mitochondria, thus, reflecting a cell-specific intracellular Ca2+ handling for basal mitochondrial activity.
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Affiliation(s)
- Christiane Klec
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cellular Signaling, Metabolism & Aging, Medical University of Graz, Graz, Austria
| | - Corina T Madreiter-Sokolowski
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cellular Signaling, Metabolism & Aging, Medical University of Graz, Graz, Austria
| | - Sarah Stryeck
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cellular Signaling, Metabolism & Aging, Medical University of Graz, Graz, Austria
| | - Vinay Sachdev
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cellular Signaling, Metabolism & Aging, Medical University of Graz, Graz, Austria.,Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Madalina Duta-Mare
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cellular Signaling, Metabolism & Aging, Medical University of Graz, Graz, Austria
| | - Benjamin Gottschalk
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cellular Signaling, Metabolism & Aging, Medical University of Graz, Graz, Austria
| | - Maria R Depaoli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cellular Signaling, Metabolism & Aging, Medical University of Graz, Graz, Austria
| | - Rene Rost
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cellular Signaling, Metabolism & Aging, Medical University of Graz, Graz, Austria
| | - Jesse Hay
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cellular Signaling, Metabolism & Aging, Medical University of Graz, Graz, Austria.,University of Montana, Division of Biological Sciences, Center for Structural & Functional Neuroscience, Missoula, MT, USA
| | - Markus Waldeck-Weiermair
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cellular Signaling, Metabolism & Aging, Medical University of Graz, Graz, Austria
| | - Dagmar Kratky
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cellular Signaling, Metabolism & Aging, Medical University of Graz, Graz, Austria.,BioTechMed, Graz, Austria
| | - Tobias Madl
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cellular Signaling, Metabolism & Aging, Medical University of Graz, Graz, Austria.,BioTechMed, Graz, Austria
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cellular Signaling, Metabolism & Aging, Medical University of Graz, Graz, Austria.,BioTechMed, Graz, Austria
| | - Wolfgang F Graier
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cellular Signaling, Metabolism & Aging, Medical University of Graz, Graz, Austria.,BioTechMed, Graz, Austria.,Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cellular Signaling, Metabolism & Aging, Medical University of Graz, Graz, Austria,
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