RESUMO
The ubiquitination and proteasome-mediated degradation of Hypoxia Inducible Factors (HIFs) is central to metazoan oxygen-sensing, but the involvement of deubiquitinating enzymes (DUBs) in HIF signalling is less clear. Here, using a bespoke DUBs sgRNA library we conduct CRISPR/Cas9 mutagenesis screens to determine how DUBs are involved in HIF signalling. Alongside defining DUBs involved in HIF activation or suppression, we identify USP43 as a DUB required for efficient activation of a HIF response. USP43 is hypoxia regulated and selectively associates with the HIF-1α isoform, and while USP43 does not alter HIF-1α stability, it facilitates HIF-1 nuclear accumulation and binding to its target genes. Mechanistically, USP43 associates with 14-3-3 proteins in a hypoxia and phosphorylation dependent manner to increase the nuclear pool of HIF-1. Together, our results highlight the multifunctionality of DUBs, illustrating that they can provide important signalling functions alongside their catalytic roles.
Assuntos
Enzimas Desubiquitinantes , Subunidade alfa do Fator 1 Induzível por Hipóxia , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Enzimas Desubiquitinantes/metabolismo , Enzimas Desubiquitinantes/genética , Mutagênese , Sistemas CRISPR-Cas , Células HEK293 , Transdução de Sinais , UbiquitinaçãoRESUMO
Cells produce considerable genotoxic formaldehyde from an unknown source. We carry out a genome-wide CRISPR-Cas9 genetic screen in metabolically engineered HAP1 cells that are auxotrophic for formaldehyde to find this cellular source. We identify histone deacetylase 3 (HDAC3) as a regulator of cellular formaldehyde production. HDAC3 regulation requires deacetylase activity, and a secondary genetic screen identifies several components of mitochondrial complex I as mediators of this regulation. Metabolic profiling indicates that this unexpected mitochondrial requirement for formaldehyde detoxification is separate from energy generation. HDAC3 and complex I therefore control the abundance of a ubiquitous genotoxic metabolite.
Assuntos
Células , Histona Desacetilases , Humanos , Células/metabolismo , Histona Desacetilases/genética , Histona Desacetilases/metabolismo , Complexo I de Transporte de ElétronsRESUMO
OBJECTIVE: To test the hypothesis that polymorphic variation in the paternally transmitted fetal IGF2 gene is associated with maternal glucose concentrations in the third trimester of pregnancy. RESEARCH DESIGN AND METHODS: A total of 17 haplotype tag single nucleotide polymorphisms in the IGF2 gene region were genotyped in 1,160 mother/partner/offspring trios from the prospective Cambridge Baby Growth Study (n = 845 trios) and the retrospective Cambridge Wellbeing Study (n = 315 trios) (3,480 samples in total). Associations were tested between inferred parent-of-origin fetal alleles, z scores of maternal glucose concentrations 60 min. after an oral glucose load performed at week 28 of pregnancy, and offspring birth weights. RESULTS: Using the minimum P value test, paternally transmitted fetal IGF2 polymorphisms were associated with maternal glucose concentrations; specifically, paternally transmitted fetal rs6578987 (P = 0.006), rs680 (P = 0.01), rs10770125 (P = 0.0002), and rs7924316 (P = 0.01) alleles were associated with increased maternal glucose concentrations in the third trimester of pregnancy and placental IGF-II contents at birth (P = 0.03). In contrast, there were no associations between maternal glucose concentrations and maternal or maternally transmitted fetal IGF2 genotypes. CONCLUSIONS: Polymorphic variation in paternally transmitted fetal IGF2 is associated with increased maternal glucose concentrations in pregnancy and could potentially alter the risk of gestational diabetes in the mother. The association may be at least partially mediated by changes in placental IGF2 expression.
Assuntos
Hiperglicemia/sangue , Hiperglicemia/etiologia , Fator de Crescimento Insulin-Like II/genética , Polimorfismo de Nucleotídeo Único , Complicações na Gravidez/sangue , Complicações na Gravidez/etiologia , Adulto , Alelos , Glicemia/análise , Estudos de Coortes , Feminino , Estudos de Associação Genética , Glucose/administração & dosagem , Humanos , Recém-Nascido , Fator de Crescimento Insulin-Like II/metabolismo , Masculino , Placenta/metabolismo , Gravidez , Proteínas da Gravidez/genética , Proteínas da Gravidez/metabolismo , Terceiro Trimestre da Gravidez , Estudos Prospectivos , Estudos Retrospectivos , Parceiros Sexuais , Reino UnidoRESUMO
Elevated [Ca(2+)](i) in human red blood cells (RBCs) activates IK1 K(+) channels leading to cell dehydration. NS309, a powerful IK1 agonist, has been shown to activate IK1 channels even at sub-physiological [Ca(2+)](i) levels. An intriguing feature of this response is its all-or-none nature, with responsive cells dehydrating fully and refractory cells retaining normal volume. We investigated the mechanism of this response suspecting cell-age involvement. We expected the younger cells, with the more vigorous plasma membrane Ca(2+) pumps (PMCA), to be the refractory cells because of their lower [Ca(2+)](i). Osmotic fragility measurements and density separation through phthalate oil were used to monitor red cell dehydration. The fraction of glycosilated haemoglobin (Hb A1c) was used to estimate the mean age of density fractionated cells. The results showed that inhibition of the PMCA by vanadate abolished the all-or-none response, that the mean age of the responsive cells was young, contrary to expectations, and that pump inhibition subsequent to an all-or-none response caused the refractory cells to dehydrate fully, suggesting that the all-or-none response resulted from a reduced efficiency of NS309 to increase the Ca(2+) sensitivity of IK1 channels in aged RBCs.
Assuntos
Cálcio/metabolismo , Eritrócitos/efeitos dos fármacos , Indóis/farmacologia , Oximas/farmacologia , Canais de Potássio/agonistas , Agonistas dos Canais de Cálcio/farmacologia , Proteínas de Transporte de Cátions/antagonistas & inibidores , Morte Celular/efeitos dos fármacos , Células Cultivadas , Senescência Celular , Desidratação/induzido quimicamente , Eritrócitos/fisiologia , Homeostase , Humanos , Vanadatos/farmacologiaRESUMO
This study was designed to test the hypothesis that polymorphic variation in maternally transmitted foetal H19 alleles is associated with offspring size at birth and alterations in maternal glucose concentrations in pregnancy. Inferred parent of origins of transmitted alleles from 13 haplotype tag SNPs in the H19 gene region from 845 family (mother, partner, offspring) trios from the prospective Cambridge Baby Growth Study and 315 trios from the retrospective Cambridge Wellbeing Study cohorts were tested for association with offspring size at birth measures, as well as maternal glucose concentrations 1 h after a glucose load at week 28 of pregnancy. The foetal rs2071094 allele inherited from the mother was associated with increased birth weight (p = 0.0015) adjusted for gestational age, parity and sex. In the Cambridge Baby Growth Study it was also associated with increased head circumference (p = 0.004), length (p = 0.017) and sum of skinfold thicknesses (p = 0.017) at birth. In contrast to these results there was no association between offspring birth weight and either the maternal rs2071094 genotype or the foetal allele from the father. None of the foetal alleles or maternal genotypes were associated with maternal glucose concentrations, neither were there any other associations with offspring birth weight. In conclusion, consistent with imprinting, common polymorphic variation in foetal H19 alleles transmitted only from the mother are associated with birth weight and other markers of size at birth. Polymorphic variation in H19 is not associated with significant changes in maternal glucose tolerance in the third trimester of pregnancy.