assembly factor
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The 26S proteasome degrades the majority of cellular proteins and affects all aspects of cellular life. Therefore, the 26S proteasome abundance, proper assembly, and activity in different life contexts need to be precisely controlled. Impaired proteasome activity is considered a causative factor in several serious disorders. Recent advances in proteasome biology have revealed that the proteasome can be activated by different factors or small molecules. Thus, activated ubiquitin-dependent proteasome degradation has effects such as extending the lifespan in different models, preventing the accumulation of protein aggregates, and reducing their negative impact on cells. Increased 26S proteasome-mediated degradation reduces proteotoxic stress and can potentially improve the efficacy of engineered degraders, such as PROTACs, particularly in situations characterized by proteasome malfunction. Here, emerging ideas and recent insights into the pharmacological activation of the proteasome at the transcriptional and posttranslational levels are summarized.
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Mitochondria are key to cellular energetics, metabolism, and signaling. Their dysfunction is linked to devastating diseases, including mitochondrial disorders, diabetes, neurodegenerative diseases, cardiac disorders, and cancer. Here, we present a knockout mouse model lacking the complex IV assembly factor SMIM20/MITRAC7. SMIM20-/- mice display cardiac pathology with reduced heart weight and cardiac output. Heart mitochondria present with reduced levels of complex IV associated with increased complex I activity, have altered fatty acid oxidation, and display elevated levels of ROS production. Interestingly, mutant mouse ventricular myocytes show unphysiological Ca2+ handling, which can be attributed to the increase in mitochondrial ROS production. Our study presents an example of a tissue-specific phenotype in the context of OXPHOS dysfunction. Moreover, our data suggest a link between complex IV dysfunction and Ca2+ handling at the endoplasmic reticulum through ROS signaling.
- MeSH
- endoplazmatické retikulum metabolismus MeSH
- kardiomyocyty metabolismus MeSH
- membránové proteiny * metabolismus genetika MeSH
- mitochondriální proteiny * metabolismus genetika MeSH
- myokard * metabolismus MeSH
- myši inbrední C57BL MeSH
- myši knockoutované MeSH
- myši MeSH
- oxidativní fosforylace MeSH
- proteiny dánia pruhovaného MeSH
- reaktivní formy kyslíku metabolismus MeSH
- respirační komplex IV * metabolismus MeSH
- srdeční mitochondrie metabolismus MeSH
- vápník metabolismus MeSH
- vápníková signalizace * MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Nucleotide excision repair (NER) is crucial for repairing bulky lesions and crosslinks in DNA caused by exogenous and endogenous genotoxins. The number of studies that have considered DNA repair as a biomarker is limited, and therefore one of the primary objectives of the European COST Action hCOMET (CA15132) was to assemble and analyse a pooled database of studies with data on NER activity. The database comprised 738 individuals, gathered from 5 laboratories that ran population studies using the comet-based in vitro DNA repair assay. NER activity data in peripheral blood mononuclear cells were normalized and correlated with various host-related factors, including sex, age, body mass index (BMI), and smoking habits. This multifaceted analysis uncovered significantly higher NER activity in female participants compared to males (1.08 ± 0.74 vs. 0.92 ± 0.71; P = .002). Higher NER activity was seen in older subjects (>30 years), and the effect of age was most pronounced in the oldest females, particularly those over 70 years (P = .001). Females with a normal BMI (<25 kg/m2) exhibited the highest levels of NER, whereas the lowest NER was observed in overweight males (BMI ≥ 25 kg/m2). No independent effect of smoking was found. After stratification by sex and BMI, higher NER was observed in smoking males (P = .017). The biological implication of higher or lower repair capacity remains unclear; the inclusion of DNA repair as a biomarker in molecular epidemiological trials should elucidate the link between health and disease status.
- MeSH
- dospělí MeSH
- excizní oprava MeSH
- index tělesné hmotnosti MeSH
- kometový test MeSH
- kouření MeSH
- leukocyty mononukleární metabolismus MeSH
- lidé středního věku MeSH
- lidé MeSH
- oprava DNA * MeSH
- poškození DNA MeSH
- senioři MeSH
- sexuální faktory MeSH
- věkové faktory MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Protein synthesis (translation) consumes a substantial proportion of cellular resources, prompting specialized mechanisms to reduce translation under adverse conditions. Ribosome inactivation often involves ribosome-interacting proteins. In both bacteria and eukaryotes, various ribosome-interacting proteins facilitate ribosome dimerization or hibernation, and/or prevent ribosomal subunits from associating, enabling the organisms to adapt to stress. Despite extensive studies on bacteria and eukaryotes, understanding factor-mediated ribosome dimerization or anti-association in archaea remains elusive. Here, we present cryo-electron microscopy structures of an archaeal 30S dimer complexed with an archaeal ribosome dimerization factor (designated aRDF), from Pyrococcus furiosus, resolved at a resolution of 3.2 Å. The complex features two 30S subunits stabilized by aRDF homodimers in a unique head-to-body architecture, which differs from the disome architecture observed during hibernation in bacteria and eukaryotes. aRDF interacts directly with eS32 ribosomal protein, which is essential for subunit association. The binding mode of aRDF elucidates its anti-association properties, which prevent the assembly of archaeal 70S ribosomes.
- MeSH
- archeální proteiny * chemie metabolismus ultrastruktura MeSH
- dimerizace MeSH
- elektronová kryomikroskopie * MeSH
- malé podjednotky ribozomu archebakteriální chemie metabolismus MeSH
- molekulární modely MeSH
- multimerizace proteinu MeSH
- Pyrococcus furiosus * metabolismus MeSH
- ribozomální proteiny * chemie metabolismus MeSH
- ribozomy metabolismus ultrastruktura chemie MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
The cytokine TNF can trigger highly proinflammatory RIPK1-dependent cell death. Here, we show that the two adapter proteins, TANK and AZI2, suppress TNF-induced cell death by regulating the activation of TBK1 kinase. Mice lacking either TANK or AZI2 do not show an overt phenotype. Conversely, animals deficient in both adapters are born in a sub-Mendelian ratio and suffer from severe multi-organ inflammation, excessive antibody production, male sterility, and early mortality, which can be rescued by TNFR1 deficiency and significantly improved by expressing a kinase-dead form of RIPK1. Mechanistically, TANK and AZI2 both recruit TBK1 to the TNF receptor signaling complex, but with distinct kinetics due to interaction with different complex components. While TANK binds directly to the adapter NEMO, AZI2 is recruited later via deubiquitinase A20. In summary, our data show that TANK and AZI2 cooperatively sustain TBK1 activity during different stages of TNF receptor assembly to protect against autoinflammation.
- MeSH
- adaptorové proteiny signální transdukční * metabolismus genetika MeSH
- buněčná smrt MeSH
- endopeptidasy MeSH
- intracelulární signální peptidy a proteiny metabolismus genetika MeSH
- lidé MeSH
- myši inbrední C57BL MeSH
- myši knockoutované * MeSH
- myši MeSH
- protein-serin-threoninkinasy * metabolismus genetika MeSH
- receptory TNF - typ I * metabolismus genetika MeSH
- serin-threoninkinasy interagující s receptory * metabolismus genetika MeSH
- signální transdukce MeSH
- TNF-alfa * metabolismus MeSH
- TNFAIP3 metabolismus genetika MeSH
- zánět metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Succinate dehydrogenase (SDH), formed by four subunits SDHA, SDHB, SDHC, SDHD, and an assembly factor SDHAF2, functions as a key respiratory enzyme. Biallelic inactivation of genes encoding any of the components, almost always in the presence of a germline mutation, causes loss of function of the entire enzyme complex (so-called SDH deficiency) and subsequent development of SDH-deficient neoplasms which include pheochromocytoma/paraganglioma, gastrointestinal stromal tumor, and renal cell carcinoma (RCC). These tumors may occur in the same patient or kindred. SDH-deficient RCC shows distinctive morphological features with vacuolated eosinophilic cytoplasm due to distinctive cytoplasmatic inclusions containing flocculent material. The diagnosis is confirmed by loss of SDHB on immunohistochemistry with positive internal control. The majority of tumors occur in the setting of germline mutations in one of the SDH genes, most commonly SDHB. The prognosis is excellent for low-grade tumors but worse for high-grade tumors with high-grade nuclei, sarcomatoid change, or coagulative necrosis. Awareness of the morphological features and low-threshold for applying SDHB immunohistochemistry help identify patients with SDH-deficient RCC and hereditary SDH-deficient tumor syndromes. In this review we summarize recent development on the clinical and genetic features, diagnostic approach, and pitfalls of SDH-deficient syndrome, focusing on SDH-deficient renal cell carcinomas.
Protein synthesis plays a major role in homeostasis and when dysregulated leads to various pathologies including cancer. To this end, imbalanced expression of eukaryotic translation initiation factors (eIFs) is not only a consequence but also a driver of neoplastic growth. eIF3 is the largest, multi-subunit translation initiation complex with a modular assembly, where aberrant expression of one subunit generates only partially functional subcomplexes. To comprehensively study the effects of eIF3 remodeling, we contrasted the impact of eIF3d, eIF3e or eIF3h depletion on the translatome of HeLa cells using Ribo-seq. Depletion of eIF3d or eIF3e, but not eIF3h reduced the levels of multiple components of the MAPK signaling pathways. Surprisingly, however, depletion of all three eIF3 subunits increased MAPK/ERK pathway activity. Depletion of eIF3e and partially eIF3d also increased translation of TOP mRNAs that encode mainly ribosomal proteins and other components of the translational machinery. Moreover, alterations in eIF3 subunit stoichiometry were often associated with changes in translation of mRNAs containing short uORFs, as in the case of the proto-oncogene MDM2 and the transcription factor ATF4. Collectively, perturbations in eIF3 subunit stoichiometry exert specific effect on the translatome comprising signaling and stress-related transcripts with complex 5' UTRs that are implicated in homeostatic adaptation to stress and cancer.
Bruton tyrosine kinase (BTK) inhibitor therapy induces peripheral blood lymphocytosis in chronic lymphocytic leukemia (CLL), which lasts for several months. It remains unclear whether nongenetic adaptation mechanisms exist, allowing CLL cells' survival during BTK inhibitor-induced lymphocytosis and/or playing a role in therapy resistance. We show that in approximately 70% of CLL cases, ibrutinib treatment in vivo increases Akt activity above pretherapy levels within several weeks, leading to compensatory CLL cell survival and a more prominent lymphocytosis on therapy. Ibrutinib-induced Akt phosphorylation (pAktS473) is caused by the upregulation of Forkhead box protein O1 (FoxO1) transcription factor, which induces expression of Rictor, an assembly protein for the mTORC2 protein complex that directly phosphorylates Akt at serine 473 (S473). Knockout or inhibition of FoxO1 or Rictor led to a dramatic decrease in Akt phosphorylation and growth disadvantage for malignant B cells in the presence of ibrutinib (or PI3K inhibitor idelalisib) in vitro and in vivo. The FoxO1/Rictor/pAktS473 axis represents an early nongenetic adaptation to B cell receptor (BCR) inhibitor therapy not requiring PI3Kδ or BTK kinase activity. We further demonstrate that FoxO1 can be targeted therapeutically and its inhibition induces CLL cells' apoptosis alone or in combination with BTK inhibitors (ibrutinib, acalabrutinib, pirtobrutinib) and blocks their proliferation triggered by T cell factors (CD40L, IL-4, and IL-21).
- MeSH
- adenin * analogy a deriváty farmakologie MeSH
- chronická lymfatická leukemie * farmakoterapie metabolismus genetika patologie MeSH
- forkhead box protein O1 * metabolismus genetika MeSH
- fosforylace MeSH
- lidé MeSH
- myši MeSH
- nádorové buněčné linie MeSH
- nádorové proteiny metabolismus genetika MeSH
- piperidiny * farmakologie MeSH
- protein RICTOR * genetika metabolismus MeSH
- proteinkinasa BTK metabolismus genetika antagonisté a inhibitory MeSH
- protoonkogenní proteiny c-akt * metabolismus genetika MeSH
- pyrazoly * farmakologie MeSH
- pyrimidiny * farmakologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Many enhancers control gene expression by assembling regulatory factor clusters, also referred to as condensates. This process is vital for facilitating enhancer communication and establishing cellular identity. However, how DNA sequence and transcription factor (TF) binding instruct the formation of high regulatory factor environments remains poorly understood. Here we developed a new approach leveraging enhancer-centric chromatin accessibility quantitative trait loci (caQTLs) to nominate regulatory factor clusters genome-wide. By analyzing TF-binding signatures within the context of caQTLs and comparing episomal versus endogenous enhancer activities, we discovered a class of regulators, 'context-only' TFs, that amplify the activity of cell type-specific caQTL-binding TFs, that is, 'context-initiator' TFs. Similar to super-enhancers, enhancers enriched for context-only TF-binding sites display high coactivator binding and sensitivity to bromodomain-inhibiting molecules. We further show that binding sites for context-only and context-initiator TFs underlie enhancer coordination, providing a mechanistic rationale for how a loose TF syntax confers regulatory specificity.
- MeSH
- chromatin * genetika metabolismus MeSH
- lidé MeSH
- lokus kvantitativního znaku * MeSH
- myši MeSH
- regulace genové exprese MeSH
- transkripční faktory * metabolismus genetika MeSH
- vazba proteinů MeSH
- vazebná místa genetika MeSH
- zesilovače transkripce * MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Obesity represents a growing problem due to its impacts on human health and reproduction. In this study, we analysed semen quality, sperm DNA integrity and gene-specific CpG methylation in 116 healthy men from normal population. The men were divided into three groups according to their body mass index (BMI), and their ejaculates were analysed using standard methods, sperm chromatin structure assay (SCSA), methylation next generation sequencing (NGS) and amplicon sequencing. The sperm methylation NGS revealed six significantly differentially methylated regions (DMRs). Using subsequent targeted amplicon sequencing in 116 men, two of the DMRs were proved as differentially methylated in sperm of men with normal BMI vs. BMI ≥ 25. The DMRs were located in the EPHA8 and ANKRD11 gene. Also, we detected a significant decline in the EPHA8, ANKRD11 and CFAP46 gene methylation in association with increasing BMI values. The genes EPHA8 and ANKRD11 are involved in the nervous system and brain development; the CFAP46 gene plays a role in a flagellar assembly and is associated with sperm motility. Significantly lower rates of motile and progressive motile sperm were observed in men with BMI ≥ 30. Our results show that excess body weight can modify CpG methylation of specific genes, affect sperm motility, and compromise sperm chromatin integrity. These factors can stand behind the observed reduced fertility in men with obesity. The methylation changes might be transmitted to their offspring through sperm, and become a basis for possible developmental and reproductive issues in the next generation.
- MeSH
- analýza spermatu * MeSH
- chromatin * metabolismus MeSH
- CpG ostrůvky MeSH
- dospělí MeSH
- index tělesné hmotnosti * MeSH
- lidé MeSH
- metylace DNA * MeSH
- mladý dospělý MeSH
- motilita spermií genetika MeSH
- obezita genetika MeSH
- spermie * metabolismus MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
