1. The ARFRP1-dependent Golgi scaffolding protein GOPC is required for insulin secretion from pancreatic β-cells.
- Author
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Wilhelmi I, Grunwald S, Gimber N, Popp O, Dittmar G, Arumughan A, Wanker EE, Laeger T, Schmoranzer J, Daumke O, and Schürmann A
- Subjects
- ADP-Ribosylation Factors genetics, Adaptor Proteins, Signal Transducing genetics, Animals, Female, Golgi Matrix Proteins genetics, HeLa Cells, Humans, Male, Mice, Mice, Knockout, Protein Transport, SNARE Proteins metabolism, trans-Golgi Network metabolism, ADP-Ribosylation Factors metabolism, Adaptor Proteins, Signal Transducing metabolism, Golgi Apparatus metabolism, Golgi Matrix Proteins metabolism, Insulin Secretion physiology, Insulin-Secreting Cells metabolism
- Abstract
Objective: Hormone secretion from metabolically active tissues, such as pancreatic islets, is governed by specific and highly regulated signaling pathways. Defects in insulin secretion are among the major causes of diabetes. The molecular mechanisms underlying regulated insulin secretion are, however, not yet completely understood. In this work, we studied the role of the GTPase ARFRP1 on insulin secretion from pancreatic β-cells., Methods: A β-cell-specific Arfrp1 knockout mouse was phenotypically characterized. Pulldown experiments and mass spectrometry analysis were employed to screen for new ARFRP1-interacting proteins. Co-immunoprecipitation assays as well as super-resolution microscopy were applied for validation., Results: The GTPase ARFRP1 interacts with the Golgi-associated PDZ and coiled-coil motif-containing protein (GOPC). Both proteins are co-localized at the trans-Golgi network and regulate the first and second phase of insulin secretion by controlling the plasma membrane localization of the SNARE protein SNAP25. Downregulation of both GOPC and ARFRP1 in Min6 cells interferes with the plasma membrane localization of SNAP25 and enhances its degradation, thereby impairing glucose-stimulated insulin release from β-cells. In turn, overexpression of SNAP25 as well as GOPC restores insulin secretion in islets from β-cell-specific Arfrp1 knockout mice., Conclusion: Our results identify a hitherto unrecognized pathway required for insulin secretion at the level of trans-Golgi sorting., (Copyright © 2020 The Authors. Published by Elsevier GmbH.. All rights reserved.)
- Published
- 2021
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