SIR2 protein, an NAD-dependent deacetylase, is localized to nucleus and is involved in life span extension by calorie restriction in yeast. In mammals, among the seven SIR2 homologues (SIRT1-7), SIRT3, 4, and 5 are localized to mitochondria. As SIRT5 mRNA levels in liver are increased by fasting, the physiological role of SIRT5 was investigated in liver of SIRT5-overexpressing transgenic (SIRT5 Tg) mice. We identified carbamoyl phosphate synthetase 1 (CPS1), a key enzyme of the urea cycle that catalyzes condensation of ammonia with bicarbonate to form carbamoyl phosphate, as a target of SIRT5 by two-dimensional electrophoresis comparing mitochondrial proteins in livers of SIRT5 Tg and wild-type mice. CPS1 protein was more deacetylated and activated in liver of SIRT5 Tg mice than in wild-type. In addition, urea production was upregulated in hepatocytes of SIRT5 Tg mice. These results agree with those of a previous study using SIRT5 knockout (KO) mice. Because ammonia generated during fasting is toxic, SIRT5 protein might play a protective role by converting ammonia to non-toxic urea through deacetylation and activation of CPS1.
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http://dx.doi.org/10.1016/j.bbrc.2010.01.081 | DOI Listing |
Orphanet J Rare Dis
January 2025
Nanjing Women and Children's Healthcare Hospital, Center of Genetic Medicine, The Affiliated Obstetrics and Gynecology Hospital With Nanjing Medical University, No.123, Tianfei Xiang, Mochou Road, Nanjing, Jiangsu, China.
Background: Ornithine transcarbamylase deficiency exhibits a high degree of clinical heterogeneity, making its screening and classification challenging in some instances. In this study, we first established a simple and stable method for testing ornithine transcarbamylase activity using micro blood from newborns, rather than relying on venous blood.
Methods: The activity of ornithine transcarbamylase was assessed by measuring the concentration of citrulline produced in the reaction with carbamoyl phosphate and ornithine, using serum, plasma or micro blood.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi
January 2025
Department of Medical Genetics and Prenatal Diagnosis, Xuzhou Maternity and Child Health Care Hospital, Xuzhou, Jiangsu 221009, China.
Objective: To explore the results of four types of Urea cycle disorders (UCDs) in newborns from the Xuzhou region, assess the efficacy of newborn screening by tandem mass spectrometry (MS/MS), and analyze their genetic characteristics.
Methods: A retrospective analysis was performed using tandem mass spectrometry to screen for inherited metabolic disorders in 691 712 newborns at the Maternal and Child Health Care Hospital of Xuzhou from November 2015 to December 2023. Ten children (cases 1-10) were diagnosed with Ornithine transcarbamylase deficiency (OTCD), Carbamoylphosphate synthase 1 deficiency (CPS1D), Arginase deficiency (ARGD), and Argininosuccinate synthase deficiency (ASSD) based on MS/MS and genetic testing.
Nat Commun
January 2025
Laboratory for Experimental Oncology and Radiobiology, Center for Experimental and Molecular Medicine, Cancer Center Amsterdam, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.
Colorectal cancer (CRC) is stratified into four consensus molecular subtypes (CMS1-4). CMS3 represents the metabolic subtype, but its wiring remains largely undefined. To identify the underlying tumorigenesis of CMS3, organoids derived from 16 genetically engineered mouse models are analyzed.
View Article and Find Full Text PDFFront Chem
December 2024
Key Laboratory of TCM Clinical Pharmacy, Shenzhen Baoan Authentic TCM Therapy Hospital, Shenzhen, China.
Background: Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) influenced by multiple factors. Berberine, an isoquinoline alkaloid derived from the root and bark of Franch., has shown promise in managing UC, but its underlying mechanisms remain unclear.
View Article and Find Full Text PDFOrphanet J Rare Dis
December 2024
Pediatric Unit, Reference Center for Inborn Errors of Metabolism, University Hospital of Nancy, INSERM UMR_S 1256, Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, Nancy, France.
Propionic aciduria (PA) and methylmalonic aciduria (MMA) are rare inherited disorders caused by defects in the propionate metabolic pathway. PA due to propionyl coenzyme A carboxylase deficiency results in accumulation of propionic acid, while in MMA, deficiency in methylmalonyl coenzyme A mutase leads to accumulation of methylmalonic acid. Hyperammonemia is related to a secondary deficiency of N-acetylglutamate (NAG), the activator of carbamoyl phosphate synthetase 1, which is an irreversible rate-limiting enzyme in the urea cycle.
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