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Mitochondrial GTP Links Nutrient Sensing to ß Cell Health, Mitochondrial Morphology, and Insulin Secretion Independent of OxPhos.
Cell Rep ; 28(3): 759-772.e10, 2019 07 16.
Artículo en Inglés | MEDLINE | ID: mdl-31315053
Mechanisms coordinating pancreatic ß cell metabolism with insulin secretion are essential for glucose homeostasis. One key mechanism of ß cell nutrient sensing uses the mitochondrial GTP (mtGTP) cycle. In this cycle, mtGTP synthesized by succinyl-CoA synthetase (SCS) is hydrolyzed via mitochondrial PEPCK (PEPCK-M) to make phosphoenolpyruvate, a high-energy metabolite that integrates TCA cycling and anaplerosis with glucose-stimulated insulin secretion (GSIS). Several strategies, including xenotopic overexpression of yeast mitochondrial GTP/GDP exchanger (GGC1) and human ATP and GTP-specific SCS isoforms, demonstrated the importance of the mtGTP cycle. These studies confirmed that mtGTP triggers and amplifies normal GSIS and rescues defects in GSIS both in vitro and in vivo. Increased mtGTP synthesis enhanced calcium oscillations during GSIS. mtGTP also augmented mitochondrial mass, increased insulin granule number, and membrane proximity without triggering de-differentiation or metabolic fragility. These data highlight the importance of the mtGTP signal in nutrient sensing, insulin secretion, mitochondrial maintenance, and ß cell health.





Texto completo: Disponible Colección: Bases de datos internacionales Base de datos: MEDLINE Idioma: Inglés Revista: Cell Rep Año: 2019 Tipo del documento: Artículo País de afiliación: Estados Unidos