Scinderin-driven Golgi Actin Remodeling coordinates GLP-1 and insulin secretion to regulate glucose homeostasis

Abstract

Maintenance of glucose homeostasis requires coordinated hormone secretion from intestinal enteroendocrine cells and pancreatic {beta}-cells, yet the intracellular mechanisms that couple nutrient sensing to endocrine output remain poorly defined. Here, we identify the actin remodeler Scinderin (SCIN) as a shared regulator of hormone secretion across these systems. SCIN is selectively expressed in enteroendocrine L-cells and pancreatic {beta}-cells, where it localizes to phosphatidylinositol-4-phosphate (PI(4)P)-enriched Golgi membranes and controls Golgi-associated actin dynamics. Loss of SCIN disrupts Golgi organization, impairs prohormone trafficking, and reduces secretory granule formation, resulting in defective nutrient-stimulated GLP-1 and insulin secretion while preserving cAMP-dependent amplification pathways. In vivo, tissue-specific deletion of Scin compromises incretin responses, {beta}-cell insulin secretion, and systemic glucose homeostasis. Consistent with these findings, SCIN expression is reduced in human diabetic {beta}-cells and associates with stress-related loss of {beta}-cell maturity. Transcriptomic analyses reveal a conserved Golgi stress program upon SCIN loss, linking intracellular trafficking defects to endocrine dysfunction. Together, our results identify SCIN-dependent Golgi actin remodeling as a rate-limiting intracellular mechanism coordinating enteroendocrine and pancreatic hormone secretion. This work uncovers a shared, targetable node controlling endocrine output, providing a mechanistic link between secretory pathway dysfunction and diabetes.