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Kim CH, Yang KH, Song YS, Yoo SS, Pu Y, Kim IH, Chung SW, Choi KW, Park JE, Lee KY. A Surface Acoustic Wave-Based PM 1.0 Fine Dust Detection System Using Full Digital Time-Interleaved Counters. SENSORS (BASEL, SWITZERLAND) 2024; 24:4149. [PMID: 39000932 PMCID: PMC11244120 DOI: 10.3390/s24134149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 06/24/2024] [Accepted: 06/25/2024] [Indexed: 07/16/2024]
Abstract
This paper proposed a fine dust detection system using time-interleaved counters in which surface acoustic wave (SAW) sensors changed the resonance point characteristic. When fine dust was applied to the SAW sensor, the resonance point decreased. The SAW oscillator made of the SAW sensor and radio frequency (RF) amplifier generated an oscillation frequency that was the same as the resonance frequency. The oscillation frequency was transferred to digital data by a 20-bit asynchronous counter. This system has two channels: a sensing channel and a reference channel. Each channel has a SAW oscillator and a 20-bit asynchronous counter. The difference of the two channel counter results is the frequency difference. Through this, it is possible to know whether fine dust adheres to the SAW sensor. The proposed circuit achieved 0.95 ppm frequency resolution when it was operated at a frequency of 460 MHz. This circuit was implemented in a TSMC 130 nm CMOS process.
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Jo MS, Kim SH, Park SY, Choi KW, Kim SH, Yoo JY, Kim BJ, Yoon JB. Fast-Response and Low-Power Self-Heating Gas Sensor Using Metal/Metal Oxide/Metal (MMOM) Structured Nanowires. ACS Sens 2024; 9:1896-1905. [PMID: 38626402 DOI: 10.1021/acssensors.3c02613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/18/2024]
Abstract
With the escalating global awareness of air quality management, the need for continuous and reliable monitoring of toxic gases by using low-power operating systems has become increasingly important. One of which, semiconductor metal oxide gas sensors have received great attention due to their high/fast response and simple working mechanism. More specifically, self-heating metal oxide gas sensors, wherein direct thermal activation in the sensing material, have been sought for their low power-consuming characteristics. However, previous works have neglected to address the temperature distribution within the sensing material, resulting in inefficient gas response and prolonged response/recovery times, particularly due to the low-temperature regions. Here, we present a unique metal/metal oxide/metal (MMOM) nanowire architecture that conductively confines heat to the sensing material, achieving high uniformity in the temperature distribution. The proposed structure enables uniform thermal activation within the sensing material, allowing the sensor to efficiently react with the toxic gas. As a result, the proposed MMOM gas sensor showed significantly enhanced gas response (from 6.7 to 20.1% at 30 ppm), response time (from 195 to 17 s at 30 ppm), and limit of detection (∼1 ppm) when compared to those of conventional single-material structures upon exposure to carbon monoxide. Furthermore, the proposed work demonstrated low power consumption (2.36 mW) and high thermal durability (1500 on/off cycles), demonstrating its potential for practical applications in reliable and low-power operating gas sensor systems. These results propose a new paradigm for power-efficient and robust self-heating metal oxide gas sensors with potential implications for other fields requiring thermal engineering.
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Amson R, Senff-Ribeiro A, Karafin T, Lespagnol A, Honoré J, Baylot V, Banroques J, Tanner NK, Chamond N, Dimitrov JD, Hoebeke J, Droin NM, Job B, Piard J, Bommer UA, Choi KW, Abdelfatah S, Efferth T, Telerman SB, Geyer FC, Reis-Filho J, Telerman A. TCTP regulates genotoxic stress and tumorigenicity via intercellular vesicular signaling. EMBO Rep 2024; 25:1962-1986. [PMID: 38548973 PMCID: PMC11014985 DOI: 10.1038/s44319-024-00108-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 02/04/2024] [Accepted: 02/21/2024] [Indexed: 04/14/2024] Open
Abstract
Oncogenic intercellular signaling is regulated by extracellular vesicles (EVs), but the underlying mechanisms remain mostly unclear. Since TCTP (translationally controlled tumor protein) is an EV component, we investigated whether it has a role in genotoxic stress signaling and malignant transformation. By generating a Tctp-inducible knockout mouse model (Tctp-/f-), we report that Tctp is required for genotoxic stress-induced apoptosis signaling via small EVs (sEVs). Human breast cancer cells knocked-down for TCTP show impaired spontaneous EV secretion, thereby reducing sEV-dependent malignant growth. Since Trp53-/- mice are prone to tumor formation, we derived tumor cells from Trp53-/-;Tctp-/f- double mutant mice and describe a drastic decrease in tumori-genicity with concomitant decrease in sEV secretion and content. Remarkably, Trp53-/-;Tctp-/f- mice show highly prolonged survival. Treatment of Trp53-/- mice with sertraline, which inhibits TCTP function, increases their survival. Mechanistically, TCTP binds DDX3, recruiting RNAs, including miRNAs, to sEVs. Our findings establish TCTP as an essential protagonist in the regulation of sEV-signaling in the context of apoptosis and tumorigenicity.
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Kim SH, Jo MS, Choi KW, Yoo JY, Kim BJ, Yang JS, Chung MK, Kim TS, Yoon JB. Ultrathin Serpentine Insulation Layer Architecture for Ultralow Power Gas Sensor. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2304555. [PMID: 37649204 DOI: 10.1002/smll.202304555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/01/2023] [Indexed: 09/01/2023]
Abstract
Toxic gases have surreptitiously influenced the health and environment of contemporary society with their odorless/colorless characteristics. As a result, a pressing need for reliable and portable gas-sensing devices has continuously increased. However, with their negligence to efficiently microstructure their bulky supportive layer on which the sensing and heating materials are located, previous semiconductor metal-oxide gas sensors have been unable to fully enhance their power efficiency, a critical factor in power-stringent portable devices. Herein, an ultrathin insulation layer with a unique serpentine architecture is proposed for the development of a power-efficient gas sensor, consuming only 2.3 mW with an operating temperature of 300 °C (≈6% of the leading commercial product). Utilizing a mechanically robust serpentine design, this work presents a fully suspended standalone device with a supportive layer thickness of only ≈50 nm. The developed gas sensor shows excellent mechanical durability, operating over 10 000 on/off cycles and ≈2 years of life expectancy under continuous operation. The gas sensor detected carbon monoxide concentrations from 30 to 1 ppm with an average response time of ≈15 s and distinguishable sensitivity to 1 ppm (ΔR/R0 = 5%). The mass-producible fabrication and heating efficiency presented here provide an exemplary platform for diverse power-efficient-related devices.
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Jo MS, Kim KH, Lee JS, Kim SH, Yoo JY, Choi KW, Kim BJ, Kwon DS, Yoo I, Yang JS, Chung MK, Park SY, Seo MH, Yoon JB. Ultrafast (∼0.6 s), Robust, and Highly Linear Hydrogen Detection up to 10% Using Fully Suspended Pure Pd Nanowire. ACS NANO 2023. [PMID: 38039345 DOI: 10.1021/acsnano.3c06806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2023]
Abstract
The high explosiveness of hydrogen gas in the air necessitates prompt detection in settings where hydrogen is used. For this reason, hydrogen sensors are required to offer rapid detection and possess superior sensing characteristics in terms of measurement range, linearity, selectivity, lifetime, and environment insensitivity according to the publicized protocol. However, previous approaches have only partially achieved the standardized requirements and have been limited in their capability to develop reliable materials for spatially accessible systems. Here, an electrical hydrogen sensor with an ultrafast response (∼0.6 s) satisfying all demands for hydrogen detection is demonstrated. Tailoring structural engineering based on the reaction kinetics of hydrogen and palladium, an optimized heating architecture that thermally activates fully suspended palladium (Pd) nanowires at a uniform temperature is designed. The developed Pd nanostructure, at a designated temperature distribution, rapidly reacts with hydrogen, enabling a hysteresis-free response from 0.1% to 10% and durable characteristics in mechanical shock and repetitive operation (>10,000 cycles). Moreover, the device selectively detects hydrogen without performance degradation in humid or carbon-based interfering gas circumstances. Finally, to verify spatial accessibility, the wireless hydrogen detection system has been demonstrated, detecting and reporting hydrogen leakage in real-time within just 1 s.
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Kim LH, Kim JY, Xu YY, Lim MA, Koo BS, Kim JH, Yoon SE, Kim YJ, Choi KW, Chang JW, Hong ST. Tctp, a unique Ing5-binding partner, inhibits the chromatin binding of Enok in Drosophila. Proc Natl Acad Sci U S A 2023; 120:e2218361120. [PMID: 37014852 PMCID: PMC10104566 DOI: 10.1073/pnas.2218361120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 02/26/2023] [Indexed: 04/05/2023] Open
Abstract
The MOZ/MORF histone acetyltransferase complex is highly conserved in eukaryotes and controls transcription, development, and tumorigenesis. However, little is known about how its chromatin localization is regulated. Inhibitor of growth 5 (ING5) tumor suppressor is a subunit of the MOZ/MORF complex. Nevertheless, the in vivo function of ING5 remains unclear. Here, we report an antagonistic interaction between Drosophila Translationally controlled tumor protein (TCTP) (Tctp) and ING5 (Ing5) required for chromatin localization of the MOZ/MORF (Enok) complex and H3K23 acetylation. Yeast two-hybrid screening using Tctp identified Ing5 as a unique binding partner. In vivo, Ing5 controlled differentiation and down-regulated epidermal growth factor receptor signaling, whereas it is required in the Yorkie (Yki) pathway to determine organ size. Ing5 and Enok mutants promoted tumor-like tissue overgrowth when combined with uncontrolled Yki activity. Tctp depletion rescued the abnormal phenotypes of the Ing5 mutation and increased the nuclear translocation of Ing5 and chromatin binding of Enok. Nonfunctional Enok promoted the nuclear translocation of Ing5 by reducing Tctp, indicating a feedback mechanism between Tctp, Ing5, and Enok to regulate histone acetylation. Therefore, Tctp is essential for H3K23 acetylation by controlling the nuclear translocation of Ing5 and chromatin localization of Enok, providing insights into the roles of human TCTP and ING5-MOZ/MORF in tumorigenesis.
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Lai CKC, Choi KW, Yao J, Tong RCF. Detection of volatile organic compounds in exhaled breath for mass screening of COVID-19 infection. Hong Kong Med J 2022; 29:175-177. [PMID: 36530162 DOI: 10.12809/hkmj2210594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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Jo MS, Kim KH, Choi KW, Lee JS, Yoo JY, Kim SH, Jin H, Seo MH, Yoon JB. Wireless and Linear Hydrogen Detection up to 4% with High Sensitivity through Phase-Transition-Inhibited Pd Nanowires. ACS NANO 2022; 16:11957-11967. [PMID: 35621510 DOI: 10.1021/acsnano.2c01783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Palladium (Pd) has been drawing increasing attention as a hydrogen (H2) detecting material due to its highly selective sensitivity to H2. However, at H2 concentrations above 2%, Pd undergoes an inevitable phase transition, causing undesirable electrical and mechanical alterations. In particular, nonlinear gas response (ΔR/R0) that accompanies phase transition has been a great bottleneck for detecting H2 in high concentrations, which is especially important as there is a risk of explosion over 4% H2. Here, we propose a phase-transition-inhibited Pd nanowire H2 sensor that can detect up to 4% H2 with high linearity and high sensitivity. Based on the calculation of the change in free energy, we designed Pd nanowires that are highly adhered to the substrate to withstand the stress that leads to phase transition. We theoretically optimized the Pd nanowire dimensions using a finite element method simulation and then experimentally fabricated the proposed sensor by exploiting a developed nanofabrication method. The proposed sensor exhibits a high sensing linearity (98.9%) with high and stable sensitivity (ΔR/R0/[H2] = 875%·bar-1) over a full range of H2 concentrations (0.1-4%). Using the fabricated Pd sensors, we have successfully demonstrated a wireless sensor module that can detect H2 with high linearity, notifying real-time H2 leakage through remote communication. Overall, our work suggests a nanostructuring strategy for detecting H2 with a phase-transition-inhibited pure Pd H2 sensor with rigorous scientific exploration.
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Compe E, Pangou E, Le May N, Elly C, Braun C, Hwang JH, Coin F, Sumara I, Choi KW, Egly JM. Phosphorylation of XPD drives its mitotic role independently of its DNA repair and transcription functions. SCIENCE ADVANCES 2022; 8:eabp9457. [PMID: 35977011 PMCID: PMC9385140 DOI: 10.1126/sciadv.abp9457] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 06/28/2022] [Indexed: 06/15/2023]
Abstract
The helicase XPD is known as a key subunit of the DNA repair/transcription factor TFIIH. However, here, we report that XPD, independently to other TFIIH subunits, can localize with the motor kinesin Eg5 to mitotic spindles and the midbodies of human cells. The XPD/Eg5 partnership is promoted upon phosphorylation of Eg5/T926 by the kinase CDK1, and conversely, it is reduced once Eg5/S1033 is phosphorylated by NEK6, a mitotic kinase that also targets XPD at T425. The phosphorylation of XPD does not affect its DNA repair and transcription functions, but it is required for Eg5 localization, checkpoint activation, and chromosome segregation in mitosis. In XPD-mutated cells derived from a patient with xeroderma pigmentosum, the phosphomimetic form XPD/T425D or even the nonphosphorylatable form Eg5/S1033A specifically restores mitotic chromosome segregation errors. These results thus highlight the phospho-dependent mitotic function of XPD and reveal how mitotic defects might contribute to XPD-related disorders.
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Mok JW, Choi KW. Modulation of Hippo signaling by Mnat9 N-acetyltransferase for normal growth and tumorigenesis in Drosophila. Cell Death Dis 2022; 13:101. [PMID: 35110540 PMCID: PMC8810759 DOI: 10.1038/s41419-022-04532-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 12/25/2021] [Accepted: 01/13/2022] [Indexed: 11/09/2022]
Abstract
AbstractHippo signaling is a conserved mechanism for controlling organ growth. Increasing evidence suggests that Hippo signaling is modulated by various cellular factors for normal development and tumorigenesis. Hence, identification of these factors is pivotal for understanding the mechanism for the regulation of Hippo signaling. Drosophila Mnat9 is a putative N-acetyltransferase that is required for cell survival by affecting JNK signaling. Here we show that Mnat9 is involved in the negative regulation of Hippo signaling. RNAi knockdown of Mnat9 in the eye disc suppresses the rough eye phenotype of overexpressing Crumbs (Crb), an upstream factor of the Hippo pathway. Conversely, Mnat9 RNAi enhances the eye phenotype caused by overexpressing Expanded (Ex) or Warts (Wts) that acts downstream to Crb. Similar genetic interactions between Mnat9 and Hippo pathway genes are found in the wing. The reduced wing phenotype of Mnat9 RNAi is suppressed by overexpression of Yorkie (Yki), while it is suppressed by knockdown of Hippo upstream factors like Ex, Merlin, or Kibra. Mnat9 co-immunoprecipitates with Mer, implying their function in a protein complex. Furthermore, Mnat9 overexpression together with Hpo knockdown causes tumorous overgrowth in the abdomen. Our data suggest that Mnat9 is required for organ growth and can induce tumorous growth by negatively regulating the Hippo signaling pathway.
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Kendall KM, Van Assche E, Andlauer TFM, Choi KW, Luykx JJ, Schulte EC, Lu Y. The genetic basis of major depression. Psychol Med 2021; 51:2217-2230. [PMID: 33682643 DOI: 10.1017/s0033291721000441] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Major depressive disorder (MDD) is a common, debilitating, phenotypically heterogeneous disorder with heritability ranges from 30% to 50%. Compared to other psychiatric disorders, its high prevalence, moderate heritability, and strong polygenicity have posed major challenges for gene-mapping in MDD. Studies of common genetic variation in MDD, driven by large international collaborations such as the Psychiatric Genomics Consortium, have confirmed the highly polygenic nature of the disorder and implicated over 100 genetic risk loci to date. Rare copy number variants associated with MDD risk were also recently identified. The goal of this review is to present a broad picture of our current understanding of the epidemiology, genetic epidemiology, molecular genetics, and gene-environment interplay in MDD. Insights into the impact of genetic factors on the aetiology of this complex disorder hold great promise for improving clinical care.
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Kandola AA, Del Pozo Cruz B, Osborn DPJ, Stubbs B, Choi KW, Hayes JF. Impact of replacing sedentary behaviour with other movement behaviours on depression and anxiety symptoms: a prospective cohort study in the UK Biobank. BMC Med 2021; 19:133. [PMID: 34134689 PMCID: PMC8210357 DOI: 10.1186/s12916-021-02007-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 05/17/2021] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Sedentary behaviour is potentially a modifiable risk factor for depression and anxiety disorders, but findings have been inconsistent. To assess the associations of sedentary behaviour with depression and anxiety symptoms and estimate the impact of replacing daily time spent in sedentary behaviours with sleep, light, or moderate to vigorous physical activity, using compositional data analysis methods. METHODS We conducted a prospective cohort study in 60,235 UK Biobank participants (mean age: 56; 56% female). Exposure was baseline daily movement behaviours (accelerometer-assessed sedentary behaviour and physical activity, and self-reported total sleep). Outcomes were depression and anxiety symptoms (Patient Health Questionnaire-9 and Generalised Anxiety Disorders-7) at follow-up. RESULTS Replacing 60 min of sedentary behaviour with light activity, moderate-to-vigorous activity, and sleep was associated with lower depression symptom scores by 1.3% (95% CI, 0.4-2.1%), 12.5% (95% CI, 11.4-13.5%), and 7.6% (95% CI, 6.9-8.4%), and lower odds of possible depression by 0.95 (95% CI, 0.94-0.96), 0.75 (95% CI, 0.74-0.76), and 0.90 (95% CI, 0.90-0.91) at follow-up. Replacing 60 min of sedentary behaviour with moderate-to-vigorous activity and sleep was associated with lower anxiety symptom scores by 6.6% (95% CI, 5.5-7.6%) and 4.5% (95% CI, 3.7-5.2%), and lower odds of meeting the threshold for a possible anxiety disorder by 0.90 (95% CI, 0.89-0.90) and 0.97 (95%CI, 0.96-0.97) at follow-up. However, replacing 60 min of sedentary behaviour with light activity was associated with higher anxiety symptom scores by 4.5% (95% CI, 3.7-5.3%) and higher odds of a possible anxiety disorder by 1.07 (95% CI, 1.06-1.08). CONCLUSIONS Sedentary behaviour is a risk factor for increased depression and anxiety symptoms in adults. Replacing sedentary behaviour with moderate-to-vigorous activity may reduce mental health risks, but more work is necessary to clarify the role of light activity.
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Son W, Choi KW. The Classic Lobe Eye Phenotype of Drosophila Is Caused by Transposon Insertion-Induced Misexpression of a Zinc-Finger Transcription Factor. Genetics 2020; 216:117-134. [PMID: 32641295 PMCID: PMC7463288 DOI: 10.1534/genetics.120.303486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 07/06/2020] [Indexed: 11/18/2022] Open
Abstract
Drosophila Lobe (L) alleles were first discovered ∼100 years ago as spontaneous dominant mutants with characteristic developmental eye defects. However, the molecular basis for L dominant eye phenotypes has not been clearly understood. A previous work reported identification of CG10109/PRAS40 as the L gene, but subsequent analyses suggested that PRAS40 may not be related to L Here, we revisited the L gene to clarify this discrepancy and understand the basis for the dominance of L mutations. Genetic analysis localized the L gene to Oaz, which encodes a homolog of the vertebrate zinc finger protein 423 (Zfp423) family transcriptional regulators. We demonstrate that RNAi knockdown of Oaz almost completely restores all L dominant alleles tested. Lrev6-3 , a revertant allele of the L2 dominant eye phenotype, has an inframe deletion in the Oaz coding sequence. Molecular analysis of L dominant mutants identified allele-specific insertions of natural transposons (roo[ ]L1 , hopper[ ]L5 , and roo[ ]Lr ) or alterations of a preexisting transposon (L2 -specific mutations in roo[ ]Mohr) in the Oaz region. In addition, we generated additional L2 -reversion alleles by CRISPR targeting at Oaz These new loss-of-function Oaz mutations suppress the dominant L eye phenotype. Oaz protein is not expressed in wild-type eye disc but is expressed ectopically in L2/+ mutant eye disc. We induced male recombination between Oaz-GAL4 insertions and the L2 mutation through homologous recombination. By using the L2 -recombined GAL4 reporters, we show that Oaz-GAL4 is expressed ectopically in L2 eye imaginal disc. Taken together, our data suggest that neomorphic L eye phenotypes are likely due to misregulation of Oaz by spontaneous transposon insertions.
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Yang DW, Choi KW. Suppression of Patronin deficiency by altered Hippo signaling in Drosophila organ development. Cell Death Differ 2020; 28:233-250. [PMID: 32737445 DOI: 10.1038/s41418-020-0597-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 07/13/2020] [Accepted: 07/16/2020] [Indexed: 01/26/2023] Open
Abstract
The microtubule network is crucial for cell structure and function. Patronin is a conserved protein involved in protecting the minus end of microtubules. Conversely, Klp10A is a kinesin-like microtubule depolymerase. Here we report the role of Drosophila Patronin and Klp10A for cell survival in developing organs. Loss of Patronin reduces the size of organs by activation of a caspase in imaginal discs. Reduced wing by Patronin RNAi is suppressed by knockdown of Spastin (Spas) but not Katanin 60, suggesting that Patronin is inhibitory to the severing function of Spas at the minus end. Patronin RNAi phenotype is also recovered by overexpressing Death-associated inhibitor of apoptosis 1 (Diap1), a Yorkie target gene. Heterozygote mutations in Hippo pathway genes, including hippo and warts (wts), suppress the Patronin RNAi wing phenotypes. Furthermore, Patronin physically interacts with Merlin and Expanded while reducing their function. Patronin and Klp10A antagonistically regulate their levels. Wing phenotypes of Patronin RNAi are rescued by knockdown of Klp10A, consistent with their antagonistic interaction. Klp10A overexpression also causes organ size reduction that is partially suppressed by Diap1 overexpression or wts heterozygote mutation. Taken together, this study suggests that the antagonistic interaction between Patronin and Klp10A is required for controlling cell survival and organ size by modulating microtubule stability and Hippo components.
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Hwang JH, Vuong LT, Choi KW. Crumbs, Galla and Xpd are required for Kinesin-5 regulation in mitosis and organ growth in Drosophila. J Cell Sci 2020; 133:jcs246801. [PMID: 32501288 DOI: 10.1242/jcs.246801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 04/29/2020] [Indexed: 12/20/2022] Open
Abstract
Xeroderma Pigmentosum D (XPD, also known as ERCC2) is a multi-functional protein involved in transcription, DNA repair and chromosome segregation. In Drosophila, Xpd interacts with Crumbs (Crb) and Galla to regulate mitosis during embryogenesis. It is unknown how these proteins are linked to mitosis. Here, we show that Crb, Galla-2 and Xpd regulate nuclear division in the syncytial embryo by interacting with Klp61F, the Drosophila mitotic Kinesin-5 associated with bipolar spindles. Crb, Galla-2 and Xpd physically interact with Klp61F and colocalize to mitotic spindles. Knockdown of any of these proteins results in similar mitotic defects. These phenotypes are restored by overexpression of Klp61F, suggesting that Klp61F is a major effector. Mitotic defects of galla-2 RNAi are suppressed by Xpd overexpression but not vice versa. Depletion of Crb, Galla-2 or Xpd results in a reduction of Klp61F levels. Reducing proteasome function restores Klp61F levels and suppresses mitotic defects caused by knockdown of Crb, Galla-2 or Xpd. Furthermore, eye growth is regulated by Xpd and Klp61F. Hence, we propose that Crb, Galla-2 and Xpd interact to maintain the level of Klp61F during mitosis and organ growth.
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Lee SR, Hong ST, Choi KW. Regulation of epithelial integrity and organ growth by Tctp and Coracle in Drosophila. PLoS Genet 2020; 16:e1008885. [PMID: 32559217 PMCID: PMC7329144 DOI: 10.1371/journal.pgen.1008885] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/01/2020] [Accepted: 05/25/2020] [Indexed: 01/28/2023] Open
Abstract
Regulation of cell junctions is crucial for the integrity of epithelial tissues and organs. Cell junctions also play roles in controlling cell proliferation for organ growth. Translationally controlled tumor protein (TCTP) is a conserved protein involved in growth control, but its role in cell junctions is unknown. Here we show that Drosophila Tctp directly interacts with the septate junction protein Coracle (Cora) to regulate epithelial integrity and organ growth. Tctp localizes together with Cora in the epidermis of the embryo. Loss of Cora reduces the level of Tctp in the epidermis but not vice versa. cora/+ or Tctp/+ single heterozygotes develop normally to adulthood. However, double heterozygotes for cora and Tctp mutations show severe disruption of epithelia causing synthetic lethality in the embryo. Double knockdown of Cora and Tctp in eye imaginal disc synergistically leads to disruption of the eye disc, resulting in a severe reduction or loss of eye and head. Conversely, double knockdown of Cora and Tctp in wing disc causes overgrowth as well as cell death. Inhibition of cell death under this condition causes hyperplastic growth of the wing disc. Tctp also shows direct and functional interaction with Cora-associated factors like Yurt and Na+/K+-ATPase. This study suggests that proper levels of Tctp and Cora are essential for the maintenance of the Cora complex and the integrity of epithelia. Our data also provide evidence that both Cora and Tctp are required to suppress overgrowth in developing wing. Organ growth depends on intercellular signaling for cell proliferation. Accumulating evidence indicates that tissue growth is also regulated by cell junctions. Translationally controlled tumor protein (TCTP) is an evolutionarily conserved protein family implicated in cancer. In Drosophila, Tctp is required for diverse cytoplasmic and nuclear functions including organ growth, DNA repair, and chromatin regulation during development. However, it is unknown whether Tctp plays an additional role in cell junctions at the membrane. Here we show that Tctp localizes together with the FERM domain protein Coracle (Cora) at the basolateral septate junctions in some tissues. Our data suggest that Cora is required for the maintenance of Tctp in the cell membrane but not vice versa. Tctp forms a complex with Cora, and the mutations in cora and Tctp genes show synergistic genetic interaction in the embryo and developing organs. Remarkably, the reduction of Cora and Tctp can induce massive overgrowth in the wing. We propose that the direct interaction of Tctp with the Cora junction complex is required for epithelial integrity and organ growth during development.
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Lee JS, Choi KW, Yoo JY, Jo MS, Yoon JB. Realization of Nanolene: A Planar Array of Perfectly Aligned, Air-Suspended Nanowires. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1906845. [PMID: 32072747 DOI: 10.1002/smll.201906845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 01/23/2020] [Indexed: 06/10/2023]
Abstract
Air suspension and alignment are fundamental requirements to make the best use of nanowires' unique properties; however, satisfying both requirements is very challenging due to the mechanical instability of air-suspended nanowires. Here, a perfectly aligned air-suspended nanowire array called "nanolene" is demonstrated, which has a high mechanical stability owing to a C-channel-shaped cross-section of the nanowires. The excellent mechanical stability is provided through geometrical modeling and finite element method simulations. The C-channel cross-section can be realized by top-down fabrication procedures, resulting in reliable demonstrations of the nanolenes with various materials and geometric parameters. The fabrication process provides large-area uniformity; therefore, nanolene can be considered as a 2D planar platform for 1D nanowire arrays. Thanks to the high mechanical stability of the proposed nanolene, perfectly aligned air-suspended nanowire arrays with an unprecedented length of 1 mm (aspect ratio ≈5100) are demonstrated. Since the nanolene can be used in an energy-efficient nanoheater, two energy-stringent sensors, namely, an air-flow sensor and a carbon monoxide gas sensor, are demonstrated. In particular, the gas sensor achieves sub-10 mW operations, which is a requirement for application in mobile phones. The proposed nanolene will pave the way to accelerate nanowire research and industrialization by providing reliable, high-performance nanowire devices.
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Mok JW, Chung H, Choi KW. Calx, a sodium/calcium exchanger, may affect lifespan in Drosophila melanogaster. MICROPUBLICATION BIOLOGY 2020; 2020:10.17912/micropub.biology.000220. [PMID: 32550491 PMCID: PMC7252295 DOI: 10.17912/micropub.biology.000220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Tran THY, Yang DW, Kim M, Lee DH, Gai M, Di Cunto F, Choi KW, Lim DS. Citron kinase interacts with LATS2 and inhibits its activity by occluding its hydrophobic phosphorylation motif. J Mol Cell Biol 2019; 11:1006-1017. [PMID: 30865227 PMCID: PMC6927243 DOI: 10.1093/jmcb/mjz013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 12/24/2018] [Accepted: 03/04/2019] [Indexed: 01/31/2023] Open
Abstract
The inhibitory effect of large tumor suppressor kinase (LATS1/2) on the activity of the oncoprotein yes-associated protein (YAP) is crucial to maintain tissue homeostasis. Proteomic studies have identified several new regulators of this process. Recently, citron kinase (CIT) was listed as a potential binding candidate of Hippo-related components, suggesting a new connection between CIT and the Hippo pathway. Aside from CIT’s role in cytokinesis, the molecular crosstalk between CIT and the Hippo pathway is largely unknown. Here, we demonstrate a role for CIT as a scaffold protein linking LATS2 and YAP. More importantly, CIT interacts with LATS2 to directly suppress LATS2 phosphorylation at the hydrophobic motif—targeted by MST1, leading to LATS2 inactivation and YAP activation. By studying their genetic interactions, we found that Sticky, the CIT homolog in Drosophila melanogaster, functions with Warts to control Drosophila eye development. Together, our study confirms citron kinase as a novel regulator of the Hippo pathway.
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Lee JS, Seo MH, Choi KW, Yoo JY, Jo MS, Yoon JB. Stress-engineered palladium nanowires for wide range (0.1%-3.9%) of H 2 detection with high durability. NANOSCALE 2019; 11:16317-16326. [PMID: 31309962 DOI: 10.1039/c9nr01975h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Pd nanowire-based H2 sensors have attracted significant attention because of their superior sensing performance. However, when exposed to H2 concentrations of more than 2%, Pd experiences volume expansion over 10%, resulting in a significant amount of mechanical stress. Thus, exposure to such high H2 concentrations causes physical destruction of Pd nanowires, such as breaks and peel-offs, leading to severe difficulty in the reliable detection of H2 over a wide concentration range. Here, we proposed a structural approach to resolve this issue by introducing a partially anchored Pd nanowire (PA-PdNW) structure. In this configuration, most of the structure was air-suspended, leaving a small portion anchored to the substrate. Air-suspension enabled PA-PdNW to expand freely, thus relieving the mechanical stress; therefore, the Pd nanowires could withstand numerous exposures to high H2 concentrations. To demonstrate the PA-PdNW structure, we developed a nano-fabrication method based on conventional semiconductor processes and successfully manufactured H2 sensor devices with uniform, perfectly aligned PA-PdNW arrays stably air-suspended with designed gaps from the substrate. The fabricated sensors achieved reliable detection of H2 in the 0.1%-3.9% concentration range with a significant resistance change. In addition, compared with fully anchored Pd nanowire (FA-PdNW) sensors, the PA-PdNW sensors showed superior durability, and the nanowires retained their initial structures even after 300 exposures to high H2 concentrations. Furthermore, it was confirmed that the PA-PdNW sensor can stably operate even in extremely humid environments at 85% relative humidity.
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Kim LH, Hong ST, Choi KW. Protein phosphatase 2A interacts with Verthandi/Rad21 to regulate mitosis and organ development in Drosophila. Sci Rep 2019; 9:7624. [PMID: 31110215 PMCID: PMC6527568 DOI: 10.1038/s41598-019-44027-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/07/2019] [Indexed: 12/20/2022] Open
Abstract
Rad21/Scc1 is a subunit of the cohesin complex implicated in gene regulation as well as sister chromatid cohesion. The level of Rad21/Scc1 must be controlled for proper mitosis and gene expression during development. Here, we identify the PP2A catalytic subunit encoded by microtubule star (mts) as a regulator of Drosophila Rad21/Verthandi (Vtd). Mutations in mts and vtd cause synergistic mitotic defects, including abnormal spindles and loss of nuclei during nuclear division in early embryo. Depletion of Mts and Vtd in developing wing synergistically reduces the Cut protein level, causing severe defects in wing growth. Mts and PP2A subunit Twins (Tws) interact with Vtd protein. Loss of Mts or Tws reduces Vtd protein level. Reduced proteasome function suppresses mitotic defects caused by mutations in mts and vtd. Taken together, this work provides evidence that PP2A is required for mitosis and wing growth by regulating the Vtd level through the proteasomal pathway.
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Kim AR, Choi KW. TRiC/CCT chaperonins are essential for organ growth by interacting with insulin/TOR signaling in Drosophila. Oncogene 2019; 38:4739-4754. [PMID: 30792539 PMCID: PMC6756063 DOI: 10.1038/s41388-019-0754-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 12/28/2018] [Accepted: 02/08/2019] [Indexed: 12/12/2022]
Abstract
Organ size is regulated by intercellular signaling for cell growth and proliferation. The TOR pathway mediates a key signaling mechanism for controlling cell size and number in organ growth. Chaperonin containing TCP-1 (CCT) is a complex that assists protein folding and function, but its role in animal development is largely unknown. Here we show that the CCT complex is required for organ growth by interacting with the TOR pathway in Drosophila. Reduction of CCT4 results in growth defects by affecting both cell size and proliferation. Loss of CCT4 causes preferential cell death anterior to the morphogenetic furrow in the eye disc and within wing pouch in the wing disc. Depletion of any CCT subunit in the eye disc results in headless phenotype. Overgrowth by active TOR signaling is suppressed by CCT RNAi. The CCT complex physically interacts with TOR signaling components including TOR, Rheb, and S6K. Loss of CCT leads to decreased phosphorylation of S6K and S6 while increasing phosphorylation of Akt. Insulin/TOR signaling is also necessary and sufficient for promoting CCT complex transcription. Our data provide evidence that the CCT complex regulates organ growth by directly interacting with the TOR signaling pathway.
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Chan AMW, Au WWY, Chao DVK, Choi K, Choi KW, Choi SMY, Chow Y, Fan CYM, Ho PL, Hui EMT, Kwong KH, Kwong BYS, Lam TP, Lam ETK, Lau KW, Lui L, Ng KHL, Wong MCS, Wong TY, Yeung CF, You JHS, Yung RWH. Antibiotic management of acute pharyngitis in primary care. Hong Kong Med J 2019; 25:58-63. [PMID: 30713150 DOI: 10.12809/hkmj187544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The Centre for Health Protection of the Department of Health has convened the Advisory Group on Antibiotic Stewardship Programme in Primary Care (the Advisory Group) to formulate guidance notes and strategies for optimising judicious use of antibiotics and enhancing the Antibiotic Stewardship Programme in Primary Care. Acute pharyngitis is one of the most common conditions among out-patients in primary care in Hong Kong. Practical recommendations on the diagnosis and antibiotic treatment of acute streptococcal pharyngitis are made by the Advisory Group based on the best available clinical evidence, local prevalence of pathogens and associated antibiotic susceptibility profiles, and common local practice.
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Abstract
Organ growth is fundamental to animal development. One of major mechanisms for growth control is mediated by the conserved Hippo signaling pathway initially identified in Drosophila. The core of this pathway in Drosophila consists of a cascade of protein kinases Hippo and Warts that negatively regulate transcriptional coactivator Yorkie (Yki). Activation of Yki promotes cell survival and proliferation to induce organ growth. A key issue in Hippo signaling is to understand how core kinase cascade is activated. Activation of Hippo kinase cascade is regulated in the upstream by at least two transmembrane proteins Crumbs and Fat that act in parallel. These membrane proteins interact with additional factors such as FERM-domain proteins Expanded and Merlin to modulate subcellular localization and function of the Hippo kinase cascade. Hippo signaling is also influenced by cytoskeletal networks and cell tension in epithelia of developing organs. These upstream events in the regulation of Hippo signaling are only partially understood. This review focuses on our current understanding of some upstream processes involved in Hippo signaling in developing Drosophila organs.
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Seo MH, Choi SJ, Park SH, Yoo JY, Lim SK, Lee JS, Choi KW, Jo MS, Kim ID, Yoon JB. Material-Independent Nanotransfer onto a Flexible Substrate Using Mechanical-Interlocking Structure. ACS NANO 2018; 12:4387-4397. [PMID: 29589909 DOI: 10.1021/acsnano.8b00159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Nanowire-transfer technology has received much attention thanks to its capability to fabricate high-performance flexible nanodevices with high simplicity and throughput. However, it is still challenging to extend the conventional nanowire-transfer method to the fabrication of a wide range of devices since a chemical-adhesion-based nanowire-transfer mechanism is complex and time-consuming, hindering successful transfer of diverse nanowires made of various materials. Here, we introduce a material-independent mechanical-interlocking-based nanowire-transfer (MINT) method, fabricating ultralong and fully aligned nanowires on a large flexible substrate (2.5 × 2 cm2) in a highly robust manner. For the material-independent nanotransfer, we developed a mechanics-based nanotransfer method, which employs a dry-removable amorphous carbon (a-C) sacrificial layer between a vacuum-deposited nanowire and the underlying master mold. The controlled etching of the sacrificial layer enables the formation of a mechanical-interlocking structure under the nanowire, facilitating peeling off of the nanowire from the master mold robustly and reliably. Using the developed MINT method, we successfully fabricated various metallic and semiconductor nanowire arrays on flexible substrates. We further demonstrated that the developed method is well suited to the reliable fabrication of highly flexible and high-performance nanoelectronic devices. As examples, a fully aligned gold (Au) microheater array exhibited high bending stability (106 cycling) and ultrafast (∼220 ms) heating operation up to ∼100 °C. An ultralong Au heater-embedded cuprous-oxide (Cu2O) nanowire chemical gas sensor showed significantly improved reversible reaction kinetics toward NO2 with 10-fold enhancement in sensitivity at 100 °C.
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