The expression of a luciferase reporter gene under the control of the human glucose 6-phosphatase gene promoter was stimulated by both dexamethasone and dibutyryl cAMP in H4IIE hepatoma cells. A cis-active element located between nucleotides -161 and -152 in the glucose 6-phosphatase gene promoter was identified and found to be necessary for both basal reporter-gene expression and induction of expression by both dibutyryl cAMP and dexamethasone. Nucleotides -161 to -152 were functionally replaced by the consensus sequence for a cAMP response element. An antibody against the cAMP response element-binding protein caused a supershift in gel-electrophoretic-mobility-shift assays using an oligonucleotide probe representing the glucose 6-phosphatase gene promoter from nucleotides -161 to -152. These results strongly indicate that in H4IIE cells the glucose 6-phosphatase gene-promoter sequence from -161 to -152 is a cAMP response element which is important for the regulation of transcription of the glucose 6-phosphatase gene by both cAMP and glucocorticoids.
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Proc Natl Acad Sci U S A
January 2025
Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
The glucose-6-phosphatase (G6Pase) is an integral membrane protein that catalyzes the hydrolysis of glucose-6-phosphate (G6P) in the endoplasmic reticulum lumen and plays a vital role in glucose homeostasis. Dysregulation or genetic mutations of G6Pase are associated with diabetes and glycogen storage disease 1a (GSD-1a). Studies have characterized the biophysical and biochemical properties of G6Pase; however, the structure and substrate recognition mechanism of G6Pase remain unclear.
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January 2025
Biochemistry Department, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt.
Ectopic olfactory receptors are expressed in nonolfactory tissues and perform diverse roles including regulation of glucose homeostasis. We explored the effect of citronellal treatment on olfactory receptor 4M1 subtype (OR4M1) signaling in insulin resistance and Type II diabetes in rats. We aimed to validate the anti-diabetic effect of citronellal through Asprosin/OR4M1 modulation.
View Article and Find Full Text PDFGlucose-6-Phosphatase (G6Pase), a key enzyme in gluconeogenesis and glycogenolysis in the mammalian liver and kidney, converts glucose-6-phosphate to glucose for maintaining systemic blood glucose homeostasis during nutrient deprivation. However, its function has remained elusive in insects, which have no need for G6Pase in sugar homeostasis since they convert glucose-6-phosphate to trehalose, their main circulating sugar, via trehalose phosphate synthase (TPS1). In this study we identify an unexpected and essential requirement for G6Pase in male fertility, specifically to produce motile sperm.
View Article and Find Full Text PDFSci Transl Med
January 2025
Institute of Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Elevated glucagon concentrations have been reported in patients with type 2 diabetes (T2D). A critical role for α cell-intrinsic mechanisms in regulating glucagon secretion was previously established through genetic manipulation of the glycolytic enzyme glucokinase (GCK) in mice. Genetic variation at the glucose-6-phosphatase catalytic subunit 2 () locus, encoding an enzyme that opposes GCK, has been reproducibly associated with fasting blood glucose and hemoglobin A1c.
View Article and Find Full Text PDFMetabolites
December 2024
Fisheries Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu 611730, China.
Rice-fish farming is an ancient and enduring aquaculture model in China. This study aimed to assess the variations in digestive enzymes, antioxidant properties, glucose metabolism, and nutritional content between reared in paddy fields and ponds. Notably, the levels of amylase and trypsin in from rice paddies were considerably higher compared to those from ponds.
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