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PHF20 is crucial for epigenetic control of starvation-induced autophagy through enhancer activation by Se Won Park;Jaehoon Kim;Sungryong Oh;Jeongyoon Lee;Joowon Cha;Hyun Sik Lee;Keun Il Kim;Daechan Park;Sung Hee Baek Nucleic Acids Research, 2022, 50(14); https://doi.org/10.1093/nar/gkac584 Abstract Autophagy is a catabolic pathway that maintains cellular homeostasis under various stress conditions, including conditions of nutrient deprivation. To elevate autophagic flux to a sufficient level under stress conditions, transcriptional activation of autophagy genes occurs to replenish autophagy components. Thus, the transcriptional and epigenetic control of the genes regulating autophagy is essential for cellular homeostasis. Here, we applied integrated transcriptomic and epigenomic profiling to reveal the roles of plant homeodomain finger protein 20 (PHF20), which is an epigenetic reader possessing methyl binding activity, in controlling the expression of autophagy genes. Phf20 deficiency led to impaired autophagic flux and autophagy gene expression under glucose starvation. Interestingly, the genome-wide characterization of chromatin states by Assay for Transposase-Accessible Chromatin (ATAC)-sequencing revealed that the PHF20-dependent chromatin remodelling occurs in enhancers that are co-occupied by dimethylated lysine 36 on histone H3 (H3K36me2). Importantly, the recognition of H3K36me2 by PHF20 was found to be highly correlated with increased levels of H3K4me1/2 at the enhancer regions. Collectively, these results indicate that PHF20 regulates autophagy genes through enhancer activation via H3K36me2 recognition as an epigenetic reader. Our findings emphasize the importance of nuclear events in the regulation of autophagy.
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- 작성자박은영
- 작성일2023-01-16
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Orientation-Mediated Luminescence Enhancement and Spin-Orbit Coupling in ZnO Single Crystals by Ali Hassan;Abbas Ahmad Khan;Yeong Hwan Ahn;Muhammad Azam;Muhammad Zubair;Wei Xue;Yu Cao Nanomaterials, 2022, 12(13); https://doi.org/10.1063/5.0092654 Abstract Temperature-, excitation wavelength-, and excitation power-dependent photoluminescence (PL) spectroscopy have been utilized to investigate the orientation-modulated near band edge emission (NBE) and deep level emission (DLE) of ZnO single crystals (SCs). The near-band-edge emission of ZnO SC with orientation exhibits strong and sharp emission intensity with suppressed deep level defects (mostly caused by oxygen vacancies Vo). Furthermore, Raman analysis reveals that orientation has dominant E2 (high) and E2 (low) modes, indicating that this direction has better crystallinity. At low temperature, the neutral donor-to-bound exciton (DoX) transition dominates, regardless of the orientation, according to the temperature-dependent PL spectra. Moreover, free-exciton (FX) transition emerges at higher temperatures in all orientations. The PL intensity dependence on the excitation power has been described in terms of power-law (I~Lα). Our results demonstrate that the α for , , and is (1.148), (1.180), and (1.184) respectively. In short, the comprehensive PL analysis suggests that DoX transitions are dominant in the NBE region, whereas oxygen vacancies (Vo) are the dominant deep levels in ZnO. In addition, the orientation contains fewer Vo-related defects with intense excitonic emission in the near band edge region than other counterparts, even at high temperature (~543 K). These results indicate that growth direction is favorable for fabricating ZnO-based highly efficient optoelectronic devices. Keywords: zinc oxide; single crystal; photoluminescence; exciton; impurities and defects
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17
- 작성자박은영
- 작성일2023-01-16
- 262
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15
- 작성자박은영
- 작성일2023-01-13
- 265
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13
- 작성자박은영
- 작성일2023-01-13
- 273
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11
- 작성자박은영
- 작성일2023-01-13
- 282
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9
- 작성자박은영
- 작성일2023-01-13
- 285
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7
- 작성자박은영
- 작성일2023-01-13
- 272
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Sustainable Catalytic Synthesis of 2,5-Diformylfuran from Various Carbohydrates by Si Ae Kim;Kihyuk Sung;June Young Jang;Sohee Bang;Seung Uk Son;Hye-Young Jang Catalysts, 2022 https://doi.org/10.3390/catal12040360 Abstract Versatile homogeneous and heterogeneous catalysts that convert carbohydrates to 2,5-diformylfuran (DFF) are essential for the development of sustainable processes for producing high-value chemicals from biomass-derived carbohydrates. An efficient catalytic system consisting of Br−, disulfide, and dimethylsulfoxide (DMSO) promoted the sustainable and selective synthesis of DFF in modest-to-good yields from various carbohydrates, such as fructose, glucose, mannose, galactose, and sucrose. Heterogeneous catalysts containing Br− also facilitated this reaction with recyclable high yields. Keywords: biomass; carbohydrates; 2,5-diformylfuran; fructose; glucose
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5
- 작성자박은영
- 작성일2023-01-13
- 278
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Highly Sensitive Two-Photon Lipid Droplet Tracker for In Vivo Screening of Drug Induced Liver Injury by Hyo Won Lee;In-Jeong Lee;Soo-Jin Lee;Yu Rim Kim;Hwan Myung Kim ACS Sensors, 2022 https://doi.org/10.1021/acssensors.1c02679 Abstract Lipid droplets (LDs) are lipid-abundant organelles found in most cell lines and primarily consist of neutral lipids. They serve as a repository of various lipids and are associated with many cellular metabolic processes, including energy storage, membrane synthesis, and protein homeostasis. LDs are prominent in a variety of diseases related to lipid regulation, including obesity, fatty liver disease, diabetes, and atherosclerosis. To monitor LD dynamics in live samples, we developed a highly selective two-photon fluorescent tracker for LDs (LD1). It exhibited outstanding sensitivity with a remarkable two-photon-action cross section (Φδmax > 600 GM), photostability, and low cytotoxicity. In human hepatocytes and in vivo mouse liver tissue imaging, LD1 showed very bright fluorescence with high LD selectivity and minimized background signal to evaluate the stages of nonalcoholic fatty liver disease. Interestingly, we demonstrated that the liver sinusoid morphology became narrower with increasing LD size and visualized the dynamics including fusion of the LDs in vivo. Moreover, real-time and dual-color TPM imaging with LD1 and a two-photon lysosome tracker could be a useful predictive screening tool in the drug development process to monitor impending drug-induced liver injury inducing drug candidates. KEYWORDS: lipid droplets fatty liver disease steatosis phospholipidosis in vivo imaging
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3
- 작성자박은영
- 작성일2023-01-13
- 274
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Substrate-binding loop interactions with pseudouridine trigger conformational changes that promote catalytic efficiency of pseudouridine kinase PUKI by Sang-HoonKim;Minjeong Kim;Daechan Park;Sujeong Byun;Sangkee Rhee Journal of Biological Chemistry, 2022 https://doi.org/10.1016/j.jbc.2022.101869 Abstract Pseudouridine, one major RNA modification, is catabolized into uracil and ribose-5′-phosphate by two sequential enzymatic reactions. In the first step, pseudouridine kinase (PUKI) phosphorylates pseudouridine to pseudouridine 5′-monophosphate. High-fidelity catalysis of pseudouridine by PUKI prevents possible disturbance of in vivo pyrimidine homeostasis. However, the molecular basis of how PUKI selectively phosphorylates pseudouridine over uridine with >100-fold greater efficiency despite minor differences in their Km values has not been elucidated. To investigate this selectivity, in this study we determined the structures of PUKI from Escherichia coli strain B (EcPUKI) in various ligation states. The structure of EcPUKI was determined to be similar to PUKI from Arabidopsis thaliana, including an α/β core domain and β-stranded small domain, with dimerization occurring via the β-stranded small domain. In a binary complex, we show that Ser30 in the substrate-binding loop of the small domain mediates interactions with the hallmark N1 atom of pseudouridine nucleobase, causing conformational changes in its quaternary structure. Kinetic and fluorescence spectroscopic analyses also showed that the Ser30-mediated interaction is a prerequisite for conformational changes and subsequent catalysis by EcPUKI. Furthermore, S30A mutation or EcPUKI complexed with other nucleosides homologous to pseudouridine but lacking the pseudouridine-specific N1 atom did not induce such conformational changes, demonstrating the catalytic significance of the proposed Ser30-mediated interaction. These analyses provide structural and functional evidence for a pseudouridine-dependent conformational change of EcPUKI and its functional linkage to catalysis.
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1
- 작성자박은영
- 작성일2023-01-13
- 274
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