| 1. |
- Campbell, Brittany B., et al.
(författare)
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Comprehensive Analysis of Hypermutation in Human Cancer
- 2017
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Ingår i: Cell. - : Elsevier BV. - 0092-8674 .- 1097-4172. ; 171:5
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Tidskriftsartikel (refereegranskat)abstract
- © 2017 Elsevier Inc. We present an extensive assessment of mutation burden through sequencing analysis of > 81,000 tumors from pediatric and adult patients, including tumors with hypermutation caused by chemotherapy, carcinogens, or germline alterations. Hypermutation was detected in tumor types not previously associated with high mutation burden. Replication repair deficiency was a major contributing factor. We uncovered new driver mutations in the replication-repair-associated DNA polymerases and a distinct impact of microsatellite instability and replication repair deficiency on the scale of mutation load. Unbiased clustering, based on mutational context, revealed clinically relevant subgroups regardless of the tumors' tissue of origin, highlighting similarities in evolutionary dynamics leading to hypermutation. Mutagens, such as UV light, were implicated in unexpected cancers, including sarcomas and lung tumors. The order of mutational signatures identified previous treatment and germline replication repair deficiency, which improved management of patients and families. These data will inform tumor classification, genetic testing, and clinical trial design. A large-scale analysis of hypermutation in human cancers provides insights into tumor evolution dynamics and identifies clinically actionable mutation signatures.
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| 2. |
- Chang, Lufen, et al.
(författare)
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The E3 ubiquitin ligase itch couples JNK activation to TNFα-induced cell death by inducing c-FLIP L turnover
- 2006
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Ingår i: Cell. - 0092-8674 .- 1097-4172. ; 124:3, s. 601-613
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Tidskriftsartikel (refereegranskat)abstract
- The proinflammatory cytokine tumor necrosis factor (TNF) α signals both cell survival and death. The biological outcome of TNFα treatment is determined by the balance between NF-κB and Jun kinase (JNK) signaling; NF-κB promotes survival, whereas JNK enhances cell death. Critically, identity of a JNK substrate that promotes TNFα-induced apoptosis has been outstanding. Here we show that TNFα-mediated JNK activation accelerates turnover of the NF-κB-induced antiapoptotic protein c-FLIP, an inhibitor of caspase-8. This is not due to direct c-FLIP phosphorylation but depends on JNK-mediated phosphorylation and activation of the E3 ubiquitin ligase Itch, which specifically ubiquitinates c-FLIP and induces its proteasomal degradation. JNK1 or Itch deficiency or treatment with a JNK inhibitor renders mice resistant in three distinct models of TNFα-induced acute liver failure, and cells from these mice do not display inducible c-FLIPL ubiquitination and degradation. Thus, JNK antagonizes NF-κB during TNFα signaling by promoting the proteasomal elimination of c-FLIPL.
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| 3. |
- Falkenberg, Maria, 1968, et al.
(författare)
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Structure casts light on mtDNA replication.
- 2009
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Ingår i: Cell. - : Elsevier BV. - 1097-4172 .- 0092-8674. ; 139:2, s. 231-3
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In this issue, Lee et al. (2009) present a crystal structure of the human mitochondrial DNA polymerase (POLgamma). The structure of this heterotrimeric enzyme lays a foundation for understanding how POLgamma mutations cause human mitochondrial disease and why some antiviral nucleoside analogs cause cellular toxicity.
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| 4. |
- Holzer, Ryan G., et al.
(författare)
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Saturated Fatty Acids Induce c-Src Clustering within Membrane Subdomains, Leading to JNK Activation
- 2011
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Ingår i: Cell. - 0092-8674 .- 1097-4172. ; 147:1, s. 173-184
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Tidskriftsartikel (refereegranskat)abstract
- Saturated fatty acids (FA) exert adverse health effects and are more likely to cause insulin resistance and type 2 diabetes than unsaturated FA, some of which exert protective and beneficial effects. Saturated FA, but not unsaturated FA, activate Jun N-terminal kinase (JNK), which has been linked to obesity and insulin resistance in mice and humans. However, it is unknown how saturated and unsaturated FA are discriminated. We now demonstrate that saturated FA activate JNK and inhibit insulin signaling through c-Src activation. FA alter the membrane distribution of c-Src, causing it to partition into intracellular membrane subdomains, where it likely becomes activated. Conversely, unsaturated FA with known beneficial effects on glucose metabolism prevent c-Src membrane partitioning and activation, which are dependent on its myristoylation, and block JNK activation. Consumption of a diabetogenic high-fat diet causes the partitioning and activation of c-Src within detergent insoluble membrane subdomains of murine adipocytes.
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| 5. |
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| 7. |
- Parra Bravo, Celeste, et al.
(författare)
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Human iPSC 4R tauopathy model uncovers modifiers of tau propagation.
- 2024
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Ingår i: Cell. - 1097-4172. ; 187:10
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Tidskriftsartikel (refereegranskat)abstract
- Tauopathies are age-associated neurodegenerative diseases whose mechanistic underpinnings remain elusive, partially due to a lack of appropriate human models. Here, we engineered human induced pluripotent stem cell (hiPSC)-derived neuronal lines to express 4R Tau and 4R Tau carrying the P301S MAPT mutation when differentiated into neurons. 4R-P301S neurons display progressive Tau inclusions upon seeding with Tau fibrils and recapitulate features of tauopathy phenotypes including shared transcriptomic signatures, autophagic body accumulation, and reduced neuronal activity. A CRISPRi screen of genes associated with Tau pathobiology identified over 500 genetic modifiers of seeding-induced Tau propagation, including retromer VPS29 and genes in the UFMylation cascade. In progressive supranuclear palsy (PSP) and Alzheimer's Disease (AD) brains, the UFMylation cascade is altered in neurofibrillary-tangle-bearing neurons. Inhibiting the UFMylation cascade invitro and invivo suppressed seeding-induced Tau propagation. This model provides a robust platform to identify novel therapeutic strategies for 4R tauopathy.
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| 8. |
- Wiel, Clotilde, 1987, et al.
(författare)
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BACH1 Stabilization by Antioxidants Stimulates Lung Cancer Metastasis
- 2019
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Ingår i: Cell. - : Elsevier BV. - 0092-8674 .- 1097-4172. ; 178:2, s. 330-345
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Tidskriftsartikel (refereegranskat)abstract
- For tumors to progress efficiently, cancer cells must overcome barriers of oxidative stress. Although dietary antioxidant supplementation or activation of endogenous antioxidants by NRF2 reduces oxidative stress and promotes early lung tumor progression, little is known about its effect on lung cancer metastasis. Here, we show that long-term supplementation with the antioxidants N-acetylcysteine and vitamin E promotes KRAS-driven lung cancer metastasis. The antioxidants stimulate metastasis by reducing levels of free heme and stabilizing the transcription factor BACH1. BACH1 activates transcription of Hexokinase 2 and Gapdh and increases glucose uptake, glycolysis rates, and lactate secretion, thereby stimulating glycolysis-dependent metastasis of mouse and human lung cancer cells. Targeting BACH1 normalized glycolysis and prevented antioxidant-induced metastasis, while increasing endogenous BACH1 expression stimulated glycolysis and promoted metastasis, also in the absence of antioxidants. We conclude that BACH1 stimulates glycolysis-dependent lung cancer metastasis and that BACH1 is activated under conditions of reduced oxidative stress.
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| 9. |
- Wu, J., et al.
(författare)
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Beige Adipocytes Are a Distinct Type of Thermogenic Fat Cell in Mouse and Human
- 2012
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Ingår i: Cell. - : Elsevier BV. - 0092-8674 .- 1097-4172. ; 150:2, s. 366-376
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Tidskriftsartikel (refereegranskat)abstract
- Brown fat generates heat via the mitochondrial uncoupling protein UCP1, defending against hypothermia and obesity. Recent data suggest that there are two distinct types of brown fat: classical brown fat derived from a myf-5 cellular lineage and UCP1-positive cells that emerge in white fat from a non-myf-5 lineage. Here, we report the isolation of "beige" cells from murine white fat depots. Beige cells resemble white fat cells in having extremely low basal expression of UCP1, but, like classical brown fat, they respond to cyclic AMP stimulation with high UCP1 expression and respiration rates. Beige cells have a gene expression pattern distinct from either white or brown fat and are preferentially sensitive to the polypeptide hormone irisin. Finally, we provide evidence that previously identified brown fat deposits in adult humans are composed of beige adipocytes. These data provide a foundation for studying this mammalian cell type with therapeutic potential.
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| 10. |
- Zhu, Xuefeng, et al.
(författare)
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Article Non-coding 7S RNA inhibits transcription via mitochondrial RNA polymerase dimerization
- 2022
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Ingår i: Cell. - : Elsevier BV. - 0092-8674 .- 1097-4172. ; 185:13
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Tidskriftsartikel (refereegranskat)abstract
- The mitochondrial genome encodes 13 components of the oxidative phosphorylation system, and altered mitochondrial transcription drives various human pathologies. A polyadenylated, non-coding RNA molecule known as 7S RNA is transcribed from a region immediately downstream of the light strand promoter in mammalian cells, and its levels change rapidly in response to physiological conditions. Here, we report that 7S RNA has a regulatory function, as it controls levels of mitochondrial transcription both in vitro and in cultured human cells. Using cryo-EM, we show that POLRMT dimerization is induced by interactions with 7S RNA. The resulting POLRMT dimer interface sequesters domains necessary for promoter recognition and unwinding, thereby preventing transcription initiation. We propose that the non-coding 7S RNA molecule is a component of a negative feedback loop that regulates mitochondrial transcription in mammalian cells.
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