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1.
Plant Cell ; 36(4): 1159-1181, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38134410

RESUMO

Plants have unique responses to fluctuating light conditions. One such response involves chloroplast photorelocation movement, which optimizes photosynthesis under weak light by the accumulation of chloroplasts along the periclinal side of the cell, which prevents photodamage under strong light by avoiding chloroplast positioning toward the anticlinal side of the cell. This light-responsive chloroplast movement relies on the reorganization of chloroplast actin (cp-actin) filaments. Previous studies have suggested that CHLOROPLAST UNUSUAL POSITIONING 1 (CHUP1) is essential for chloroplast photorelocation movement as a regulator of cp-actin filaments. In this study, we conducted comprehensive analyses to understand CHUP1 function. Functional, fluorescently tagged CHUP1 colocalized with and was coordinately reorganized with cp-actin filaments on the chloroplast outer envelope during chloroplast movement in Arabidopsis thaliana. CHUP1 distribution was reversibly regulated in a blue light- and phototropin-dependent manner. X-ray crystallography revealed that the CHUP1-C-terminal domain shares structural homology with the formin homology 2 (FH2) domain, despite lacking sequence similarity. Furthermore, the CHUP1-C-terminal domain promoted actin polymerization in the presence of profilin in vitro. Taken together, our findings indicate that CHUP1 is a plant-specific actin polymerization factor that has convergently evolved to assemble cp-actin filaments and enables chloroplast photorelocation movement.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Actinas , Proteínas de Arabidopsis/genética , Polimerização , Proteínas de Cloroplastos/genética , Arabidopsis/genética , Citoesqueleto de Actina , Cloroplastos/fisiologia , Luz , Movimento
2.
Mol Cell ; 74(3): 494-507.e8, 2019 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-30930054

RESUMO

N6-methyladenosine (m6A) is the most abundant internal modification in RNAs and plays regulatory roles in a variety of biological and physiological processes. Despite its important roles, the molecular mechanism underlying m6A-mediated gene regulation is poorly understood. Here, we show that m6A-containing RNAs are subject to endoribonucleolytic cleavage via YTHDF2 (m6A reader protein), HRSP12 (adaptor protein), and RNase P/MRP (endoribonucleases). We demonstrate that HRSP12 functions as an adaptor to bridge YTHDF2 and RNase P/MRP, eliciting rapid degradation of YTHDF2-bound RNAs. Transcriptome-wide analyses show that m6A RNAs that are preferentially targeted for endoribonucleolytic cleavage have an HRSP12-binding site and a RNase P/MRP-directed cleavage site upstream and downstream of the YTHDF2-binding site, respectively. We also find that a subset of m6A-containing circular RNAs associates with YTHDF2 in an HRSP12-dependent manner and is selectively downregulated by RNase P/MRP. Thus, our data expand the known functions of RNase P/MRP to endoribonucleolytic cleavage of m6A RNAs.


Assuntos
Adenosina/análogos & derivados , Proteínas de Choque Térmico/genética , Estabilidade de RNA/genética , Proteínas de Ligação a RNA/genética , Ribonuclease P/genética , Ribonucleases/genética , Adenosina/genética , Dioxigenase FTO Dependente de alfa-Cetoglutarato/genética , Sítios de Ligação/genética , Escherichia coli/genética , Regulação da Expressão Gênica/genética , Células HeLa , Humanos , Metiltransferases/genética , RNA/genética , Processamento Pós-Transcricional do RNA/genética , RNA Circular , Transcriptoma/genética
3.
Mol Cell ; 73(6): 1138-1149.e6, 2019 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-30901564

RESUMO

The nuclear factor (NF)-κB pathway plays a central role in inflammatory and immune responses, with aberrant activation of NF-κB signaling being implicated in various human disorders. Here, we show that mammalian ste20-like kinase 1 (MST1) is a previously unrecognized component of the tumor necrosis factor α (TNFα) receptor 1 signaling complex (TNF-RSC) and attenuates TNFα-induced NF-κB signaling. Genetic ablation of MST1 in mouse embryonic fibroblasts and bone marrow-derived macrophages potentiated the TNFα-induced increase in IκB kinase (IKK) activity, as well as the expression of NF-κB target genes. TNFα induced the recruitment of MST1 to TNF-RSC and its interaction with HOIP, the catalytic component of the E3 ligase linear ubiquitin assembly complex (LUBAC). Furthermore, MST1 activated in response to TNFα stimulation mediates the phosphorylation of HOIP and thereby inhibited LUBAC-dependent linear ubiquitination of NEMO/IKKγ. Together, our findings suggest that MST1 negatively regulates TNFα-induced NF-κB signaling by targeting LUBAC.


Assuntos
Fibroblastos/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , NF-kappa B/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Fator de Necrose Tumoral alfa/farmacologia , Ubiquitina-Proteína Ligases/metabolismo , Animais , Fibroblastos/enzimologia , Células HEK293 , Humanos , Quinase I-kappa B/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Macrófagos/enzimologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Complexos Multienzimáticos , Fosforilação , Proteínas Serina-Treonina Quinases/deficiência , Proteínas Serina-Treonina Quinases/genética , Receptores Tipo I de Fatores de Necrose Tumoral/genética , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo , Transdução de Sinais/efeitos dos fármacos , Fator 2 Associado a Receptor de TNF/genética , Fator 2 Associado a Receptor de TNF/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitinação
4.
EMBO J ; 41(13): e109755, 2022 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-35593068

RESUMO

The ClpP serine peptidase is a tetradecameric degradation molecular machine involved in many physiological processes. It becomes a competent ATP-dependent protease when coupled with Clp-ATPases. Small chemical compounds, acyldepsipeptides (ADEPs), are known to cause the dysregulation and activation of ClpP without ATPases and have potential as novel antibiotics. Previously, structural studies of ClpP from various species revealed its structural details, conformational changes, and activation mechanism. Although product release through side exit pores has been proposed, the detailed driving force for product release remains elusive. Herein, we report crystal structures of ClpP from Bacillus subtilis (BsClpP) in unforeseen ADEP-bound states. Cryo-electron microscopy structures of BsClpP revealed various conformational states under different pH conditions. To understand the conformational change required for product release, we investigated the relationship between substrate hydrolysis and the pH-lowering process. The production of hydrolyzed peptides from acidic and basic substrates by proteinase K and BsClpP lowered the pH values. Our data, together with those of previous findings, provide insight into the molecular mechanism of product release by the ClpP self-compartmentalizing protease.


Assuntos
Endopeptidase Clp , Peptídeo Hidrolases , Microscopia Crioeletrônica , Endopeptidase Clp/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Peptídeo Hidrolases/metabolismo
5.
Mol Cell ; 70(5): 920-935.e7, 2018 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-29883609

RESUMO

Receptor-interacting protein kinase-3 (RIP3 or RIPK3) is a central protein in necroptosis, but posttranslational processes that regulate RIP3 activity and stability remain poorly understood. Here, we identify pellino E3 ubiquitin protein ligase 1 (PELI1) as an E3 ligase that targets RIP3 for proteasome-dependent degradation. Phosphorylation of RIP3 on T182 leads to interaction with the forkhead-associated (FHA) domain of PELI1 and PELI1-mediated K48-linked polyubiquitylation of RIP3 on K363. This same phosphorylation event is also important for RIP3 kinase activity; thus, PELI1 preferentially targets kinase-active RIP3 for degradation. PELI1-mediated RIP3 degradation effectively prevents cell death triggered by RIP3 hyperactivation. Importantly, upregulated RIP3 expression in keratinocytes from toxic epidermal necrolysis (TEN) patients is correlated with low expression of PELI1, suggesting that loss of PELI1 may play a role in the pathogenesis of TEN. We propose that PELI1 may function to control inadvertent activation of RIP3, thus preventing aberrant cell death and maintaining cellular homeostasis.


Assuntos
Queratinócitos/enzimologia , Proteínas Nucleares/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Síndrome de Stevens-Johnson/enzimologia , Ubiquitina-Proteína Ligases/metabolismo , Animais , Morte Celular , Fibroblastos/enzimologia , Fibroblastos/patologia , Células HEK293 , Células HT29 , Células HeLa , Humanos , Queratinócitos/patologia , Camundongos , Proteínas Nucleares/genética , Fosforilação , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Proteólise , Proteína Serina-Treonina Quinases de Interação com Receptores/genética , Transdução de Sinais , Síndrome de Stevens-Johnson/genética , Síndrome de Stevens-Johnson/patologia , Ubiquitina-Proteína Ligases/genética , Ubiquitinação
6.
Circulation ; 149(10): 774-787, 2024 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-38018436

RESUMO

BACKGROUND: Cholesterol efflux capacity (CEC) predicts cardiovascular disease independently of high-density lipoprotein (HDL) cholesterol levels. Isolated small HDL particles are potent promoters of macrophage CEC by the ABCA1 (ATP-binding cassette transporter A1) pathway, but the underlying mechanisms are unclear. METHODS: We used model system studies of reconstituted HDL and plasma from control and lecithin-cholesterol acyltransferase (LCAT)-deficient subjects to investigate the relationships among the sizes of HDL particles, the structure of APOA1 (apolipoprotein A1) in the different particles, and the CECs of plasma and isolated HDLs. RESULTS: We quantified macrophage and ABCA1 CEC of 4 distinct sizes of reconstituted HDL. CEC increased as particle size decreased. Tandem mass spectrometric analysis of chemically cross-linked peptides and molecular dynamics simulations of APOA1, the major protein of HDL, indicated that the mobility of C-terminus of that protein was markedly higher and flipped off the surface in the smallest particles. To explore the physiological relevance of the model system studies, we isolated HDL from LCAT-deficient subjects, whose small HDLs (like reconstituted HDLs) are discoidal and composed of APOA1, cholesterol, and phospholipid. Despite their very low plasma levels of HDL particles, these subjects had normal CEC. In both the LCAT-deficient subjects and control subjects, the CEC of isolated extra-small HDL (a mixture of extra-small and small HDL by calibrated ion mobility analysis) was 3- to 5-fold greater than that of the larger sizes of isolated HDL. Incubating LCAT-deficient plasma and control plasma with human LCAT converted extra-small and small HDL particles into larger particles, and it markedly inhibited CEC. CONCLUSIONS: We present a mechanism for the enhanced CEC of small HDLs. In smaller particles, the C-termini of the 2 antiparallel molecules of APOA1 are "flipped" off the lipid surface of HDL. This extended conformation allows them to engage with ABCA1. In contrast, the C-termini of larger HDLs are unable to interact productively with ABCA1 because they form a helical bundle that strongly adheres to the lipid on the particle. Enhanced CEC, as seen with the smaller particles, predicts decreased cardiovascular disease risk. Thus, extra-small and small HDLs may be key mediators and indicators of the cardioprotective effects of HDL.


Assuntos
Apolipoproteína A-I , Doenças Cardiovasculares , Humanos , Apolipoproteína A-I/metabolismo , Doenças Cardiovasculares/metabolismo , Lipoproteínas HDL/metabolismo , Colesterol , Transportador 1 de Cassete de Ligação de ATP/genética , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Macrófagos/metabolismo , HDL-Colesterol
7.
Proc Natl Acad Sci U S A ; 119(31): e2209597119, 2022 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-35878037

RESUMO

N-degron pathways are proteolytic systems that target proteins bearing N-terminal (Nt) degradation signals (degrons) called N-degrons. Nt-Arg of a protein is among Nt-residues that can be recognized as destabilizing ones by the Arg/N-degron pathway. A proteolytic cleavage of a protein can generate Arg at the N terminus of a resulting C-terminal (Ct) fragment either directly or after Nt-arginylation of that Ct-fragment by the Ate1 arginyl-tRNA-protein transferase (R-transferase), which uses Arg-tRNAArg as a cosubstrate. Ate1 can Nt-arginylate Nt-Asp, Nt-Glu, and oxidized Nt-Cys* (Cys-sulfinate or Cys-sulfonate) of proteins or short peptides. Ate1 genes of fungi, animals, and plants have been cloned decades ago, but a three-dimensional structure of Ate1 remained unknown. A detailed mechanism of arginylation is unknown as well. We describe here the crystal structure of the Ate1 R-transferase from the budding yeast Kluyveromyces lactis. The 58-kDa R-transferase comprises two domains that recognize, together, an acidic Nt-residue of an acceptor substrate, the Arg residue of Arg-tRNAArg, and a 3'-proximal segment of the tRNAArg moiety. The enzyme's active site is located, at least in part, between the two domains. In vitro and in vivo arginylation assays with site-directed Ate1 mutants that were suggested by structural results yielded inferences about specific binding sites of Ate1. We also analyzed the inhibition of Nt-arginylation activity of Ate1 by hemin (Fe3+-heme), and found that hemin induced the previously undescribed disulfide-mediated oligomerization of Ate1. Together, these results advance the understanding of R-transferase and the Arg/N-degron pathway.


Assuntos
Aminoaciltransferases , Arginina , Modelos Moleculares , Aminoaciltransferases/química , Aminoaciltransferases/genética , Aminoaciltransferases/metabolismo , Animais , Arginina/metabolismo , Hemina/metabolismo , Mutação , Peptídeos/metabolismo , Estrutura Terciária de Proteína , Proteínas/metabolismo , Proteólise , RNA de Transferência de Arginina/metabolismo
8.
Ann Surg Oncol ; 31(8): 4882-4893, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38861205

RESUMO

BACKGROUND: This study sought to identify associations between the Yost Index, a geocoded area neighborhood socioeconomic status (nSES) score, and race/ethnicity with patient refusal of recommended surgery for metastatic bone disease. METHODS: Patients with metastatic bone disease were extracted from the Surveillance, Epidemiology, and End Results database. The Yost Index was geocoded using factor analysis and categorized into quintiles using census tract-level American Community Service (ACS) 5-year estimates and seven nSES measures. Multivariable logistic regression models calculated odds ratios (ORs) of refusal of recommended surgery and 95% confidence intervals (CIs), adjusting for clinical covariates. RESULTS: A total of 138,257 patients were included, of which 14,943 (10.8%) were recommended for surgical resection. Patients in the lowest nSES quintile had 57% higher odds of refusing surgical treatment than those in the highest quintile (aOR = 1.57, 95% CI 1.30-1.91, p < 0.001). Patients in the lowest nSES quintile also had a 31.2% higher age-adjusted incidence rate of not being recommended for surgery compared with those in the highest quintile (186.4 vs. 142.1 per 1 million, p < 0.001). Black patients had 34% higher odds of refusing treatment compared with White patients (aOR = 1.34, 95% CI 1.14-1.58, p = 0.003). Advanced age, unmarried status, and patients with aggressive cancer subtypes were associated with higher odds of refusing surgery (p < 0.001). CONCLUSIONS: nSES and race/ethnicity are independent predictors of a patient refusing surgery for metastatic cancer to bone, even after adjusting for various clinical covariates. Effective strategies for addressing these inequalities and improving the access and quality of care of patients with a lower nSES and minority backgrounds are needed.


Assuntos
Neoplasias Ósseas , Programa de SEER , Classe Social , Recusa do Paciente ao Tratamento , Humanos , Feminino , Masculino , Neoplasias Ósseas/secundário , Neoplasias Ósseas/cirurgia , Idoso , Pessoa de Meia-Idade , Recusa do Paciente ao Tratamento/estatística & dados numéricos , Seguimentos , Prognóstico , Adulto , Características da Vizinhança , Estados Unidos/epidemiologia
9.
Opt Lett ; 49(8): 1945-1948, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38621047

RESUMO

Group III-nitride semiconductors with tubular structures offer significant potential across various applications, including optics, electronics, and chemical sensors. However, achieving tailored fabrication of these structures remains a challenge. In this study, we present a novel, to the best of our knowledge, method to fabricate micro-sized tubular structures by rolling the layered membrane of group III-nitride alloys utilizing the photoelectrochemical (PEC) etching. To customize the geometry of the tubular structure, we conducted an analytic calculation to predict the strain and deformation for the layered membrane. Based on the calculations, we designed and fabricated an AlGaN/GaN/InGaN/n-GaN/ sapphire structure using metal-organic chemical vapor deposition (MOCVD). Photolithography and PEC etching were employed to selectively etch the sacrificial InGaN layer. We investigated the changes of optical properties of the rolled-up structure by utilizing micro-photoluminescence (µ-PL) and micro-Raman spectroscopy.

10.
Eur J Clin Pharmacol ; 80(3): 367-382, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38147074

RESUMO

PURPOSE: The increased use of proton pump inhibitors (PPIs) in the elderly has raised concerns about potential severe adverse effects. Our systematic review investigated the mortality associated with PPI use in elderly populations. METHODS: We searched MEDLINE, EMBASE, and the Cochrane Library for relevant publications until August 2022. We included randomized controlled trials (RCTs), quasi-RCTs, and observational studies on the association between proton pump inhibitors and mortality in the elderly. To estimate the pooled relative risk (RR) and 95% confidence interval (CI), the inverse-variance random effect model was used. Heterogeneity was assessed using the I2 test. Subgroup analyses were performed by follow-up period, population, and study design. RESULTS: A total of 4 RCTs and 36 cohort studies were included in the meta-analysis. Four RCTs showed that there was no significant association between PPIs and the risk of death. From 23 observational studies (26 cohorts), the use of proton pump inhibitors was not significantly associated with increased mortality in the elderly (RR 1.14; 95% CI, 0.90-1.45). However, when controlling for covariates from 33 observational studies (41 cohorts), proton pump inhibitors in older adults aged 50 years or more were significantly associated with a 15% higher risk of mortality compared to nonusers (RR 1.15; 95% CI, 1.10-1.20). CONCLUSIONS: Our meta-analysis of RCTs found that PPIs did not show a significant association with increased mortality risk in older adults. However, the meta-analysis of cohort studies and long-term follow-up studies showed a higher increased risk of death with PPI use in older adults. The prescription of PPIs in patients aged 50 years or older should be carefully considered.

11.
Artigo em Inglês | MEDLINE | ID: mdl-38980349

RESUMO

PURPOSE: This study aimed to investigate the effects of subconjunctival injection of aflibercept, a soluble protein decoy for VEGFR-1 and VEGFR-2, on corneal angiogenesis and VEGFR-expressing CD11b+ cells in a mouse model of suture-induced corneal neovascularization. METHODS: Corneal neovascularization was induced in BALB/c mice by placing three sutures on the cornea. Immediately after surgery, either 200 µg aflibercept (5 µL) or an equal volume of phosphate-buffered saline (PBS) was administered into the subconjunctival space. Seven days after later, corneal new vessels were quantified through clinical examination and measurement of the CD31-stained area in corneal flat mounts. The levels of pro-angiogenic and inflammatory markers in the cornea were evaluated using RT-qPCR. The percentages of VEGFR-2+CD11b+ cells and VEGFR-3+CD11b+ cells were analyzed in the cornea, blood, and draining cervical lymph nodes (DLNs) using flow cytometry. RESULTS: Subconjunctival injection of aflibercept significantly reduced the growth of corneal new vessels compared to subconjunctival PBS injection. The mRNA levels of Cd31, vascular growth factors (Vegfc and Angpt1), and pro-angiogenic/inflammatory markers (Tek/Tie2, Mrc1, Mrc2, and Il6) in the cornea were downregulated by subconjunctival aflibercept. Also, the percentage of VEGFR-3+CD11b+ cells in the cornea, blood, and DLNs was decreased by aflibercept, whereas that of VEGFR-2+CD11b+ cells was unaffected. CONCLUSION: Subconjunctival aflibercept administration inhibits inflammatory angiogenesis in the cornea and reduces the numbers of cornea-infiltrating and circulating VEGFR-3+CD11b+ cells.

12.
BMC Urol ; 24(1): 65, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38515108

RESUMO

BACKGROUND: This work aimed to identify a method to achieve improved stone targeting and safety in shockwave lithotripsy by accounting for respiration. METHODS: We set up an electromotive device simulating renal movement during respiration to place artificial stones within the phantom gel, measuring stone weight changes before and after shockwave exposure and the cavitation damage. We conducted clinical trials using respiratory masks and sensors to monitor and analyze patient respiration during shockwave lithotripsy. RESULTS: The in vitro efficiency of lithotripsy was higher when adjusted for respiration than when respiration was not adjusted for. Slow respiration showed the best efficiency with higher hit rates when not adjusted for respiration. Cavitation damage was also lowest during slow respiration. The clinical study included 52 patients. Respiratory regularity was maintained above 90% in regular respiration. When respiration was regular, the lithotripsy rate was about 65.6%, which stayed at about 40% when respiration was irregular. During the lithotripsy, the participants experienced various events, such as sleep, taking off their masks, talking, movement, coughing, pain, nervousness, and hyperventilation. The generation of shockwaves based on respiratory regularity could reduce pain in patients. CONCLUSION: These results suggest a more accurate lithotripsy should be performed according to respiratory regularity.


Assuntos
Cálculos Renais , Litotripsia , Humanos , Cálculos Renais/terapia , Rim , Litotripsia/métodos , Projetos de Pesquisa , Imagens de Fantasmas , Dor , Resultado do Tratamento
13.
J Clin Lab Anal ; 38(7): e25034, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38525919

RESUMO

BACKGROUND: Accurate quantification of the BCR::ABL1 transcripts is essential for measurable residual disease (MRD) monitoring in chronic myeloid leukemia (CML) after tyrosine kinase inhibitor (TKI) treatment. This study evaluated the newly developed digital real-time PCR method, Dr. PCR, as an alternative reverse transcription-PCR (qRT-PCR) for MRD detection. METHODS: The performance of Dr. PCR was assessed using reference and clinical materials. Precision, linearity, and correlation with qRT-PCR were evaluated. MRD levels detected by Dr. PCR were compared with qRT-PCR, and practical advantages were investigated. RESULTS: Dr. PCR detected MRD up to 0.0032%IS (MR4.5) with excellent precision and linearity and showed a strong correlation with qRT-PCR results. Notably, Dr. PCR identified higher levels of MRD in 12.7% (29/229) of patients than qRT-PCR, including six cases of MR4, which is a critical level for TKI discontinuation. Dr. PCR also allowed for sufficient ABL1 copies in all cases, while qRT-PCR necessitated multiple repeat tests in 3.5% (8/229) of cases. CONCLUSION: Our study provides a body of evidence supporting the clinical application of Dr. PCR as a rapid and efficient method for assessing MRD in patients with CML under the current treatment regimen.


Assuntos
Proteínas de Fusão bcr-abl , Leucemia Mielogênica Crônica BCR-ABL Positiva , Neoplasia Residual , Reação em Cadeia da Polimerase em Tempo Real , Humanos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Proteínas de Fusão bcr-abl/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Neoplasia Residual/genética , Reprodutibilidade dos Testes
14.
Proc Natl Acad Sci U S A ; 118(43)2021 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-34663735

RESUMO

N-degron pathways are proteolytic systems that recognize proteins bearing N-terminal (Nt) degradation signals (degrons) called N-degrons. Our previous work identified Gid4 as a recognition component (N-recognin) of the Saccharomyces cerevisiae proteolytic system termed the proline (Pro)/N-degron pathway. Gid4 is a subunit of the oligomeric glucose-induced degradation (GID) ubiquitin ligase. Gid4 targets proteins through the binding to their Nt-Pro residue. Gid4 is also required for degradation of Nt-Xaa-Pro (Xaa is any amino acid residue) proteins such as Nt-[Ala-Pro]-Aro10 and Nt-[Ser-Pro]-Pck1, with Pro at position 2. Here, we show that specific aminopeptidases function as components of the Pro/N-degron pathway by removing Nt-Ala or Nt-Ser and yielding Nt-Pro, which can be recognized by Gid4-GID. Nt-Ala is removed by the previously uncharacterized aminopeptidase Fra1. The enzymatic activity of Fra1 is shown to be essential for the GID-dependent degradation of Nt-[Ala-Pro]-Aro10. Fra1 can also trim Nt-[Ala-Pro-Pro-Pro] (stopping immediately before the last Pro) and thereby can target for degradation a protein bearing this Nt sequence. Nt-Ser is removed largely by the mitochondrial/cytosolic/nuclear aminopeptidase Icp55. These advances are relevant to eukaryotes from fungi to animals and plants, as Fra1, Icp55, and the GID ubiquitin ligase are conserved in evolution. In addition to discovering the mechanism of targeting of Xaa-Pro proteins, these insights have also expanded the diversity of substrates of the Pro/N-degron pathway.


Assuntos
Aminopeptidases/metabolismo , Dipeptidases/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/enzimologia , Proteólise , Especificidade por Substrato
15.
Foodborne Pathog Dis ; 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38442228

RESUMO

Multidrug-resistant (MDR) Salmonella enterica serovar Agona infections affect public health globally. This investigation aimed to ascertain the antimicrobial resistance profiles and molecular characteristics of Salmonella Agona isolates obtained from food-producing animals. A total of 209 Salmonella Agona isolates were recovered from mostly chickens (139 isolates), pigs (56 isolates), cattle (11 isolates), and ducks (3 isolates) between 2010 and 2020 in South Korea. In addition, these Salmonella Agona isolates were obtained from 25 slaughterhouses nationwide. Furthermore, this serotype suddenly increased in chickens in 2020. Salmonella Agona from chickens showed high resistance (69-83%) to ampicillin, streptomycin, tetracycline, trimethoprim/sulfamethoxazole, and chloramphenicol. Moreover, chicken/duck isolates (83.1%) showed significantly higher levels of MDR than cattle/pig isolates (1.5%). For molecular analysis by pulsed-field gel electrophoresis, infrared spectroscopy biotyping, and multilocus sequence typing in combination, a total of 23 types were observed. Especially two major types, P1-III-2-13 and P1-IV-2-13, comprised 59.3% of the total isolates spreading in most farms. Moreover, Salmonella Agona sequence type (ST)13 was predominant (96.7%) among three different STs (ST13, ST11, and ST292) widely detected in chickens (94.3%) in most farms located nationwide. Taken together, MDR Salmonella Agona in chickens might pose a potential risk to public health through direct contact or the food chain.

16.
Nano Lett ; 23(20): 9626-9633, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37819875

RESUMO

Recently, neuromorphic computing has been proposed to overcome the drawbacks of the current von Neumann computing architecture. Especially, spiking neural network (SNN) has received significant attention due to its ability to mimic the spike-driven behavior of biological neurons and synapses, potentially leading to low-power consumption and other advantages. In this work, we designed the indium-gallium-zinc oxide (IGZO) channel charge-trap flash (CTF) synaptic device based on a HfO2/Al2O3/Si3N4/Al2O3 layer. Our IGZO-based CTF device exhibits synaptic functions with 128 levels of synaptic weight states and spike-timing-dependent plasticity. The SNN-restricted Boltzmann machine was used to simulate the fabricated CTF device to evaluate the efficiency for the SNN system, achieving the high pattern-recognition accuracy of 83.9%. We believe that our results show the suitability of the fabricated IGZO CTF device as a synaptic device for neuromorphic computing.

17.
Int J Nurs Pract ; 30(2): e13151, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36945789

RESUMO

AIMS: This study aimed to examine the relationship between heart failure knowledge, self-efficacy, social support, grit and self-care behaviour in patients with heart failure and to identify factors associated with patients' self-care behaviour. BACKGROUND: Most patients with heart failure are not as active in implementing self-care behavioural practices as recommended by the guidelines. DESIGN: This descriptive cross-sectional study was designed based on Bandura's Social Cognitive Theory. METHODS: This study included 138 patients who were diagnosed with heart failure in an outpatient department of cardiology at a tertiary hospital in Korea. Data were collected between July and October 2020 using a structured questionnaire and electronic medical records. Data were analysed using the SPSS/WIN 27.0 program. RESULTS: Grit had the strongest association with self-care behaviour among patients with heart failure, followed by social support, self-efficacy and heart failure knowledge. These variables accounted for approximately 52% of the variance in self-care behaviour. CONCLUSIONS: Health-care professionals should assess patients' grit and develop patient-tailored grit enhancement programmes. Based on the social cognitive theory, nursing intervention programmes that can simultaneously manage cognitive (knowledge and self-efficacy), social and environmental (social support) and behavioural support (grit) factors should be developed and applied to nursing practices to promote self-care.


Assuntos
Insuficiência Cardíaca , Autocuidado , Humanos , Estudos Transversais , Autoeficácia , Insuficiência Cardíaca/terapia , Inquéritos e Questionários
18.
Small ; 19(47): e2303263, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37434049

RESUMO

A cobalt phthalocyanine having an electron-poor CoN4 (+δ) in its phthalocyanine moiety was presented as an electrocatalyst for hydrogen peroxide oxidation reaction (HPOR). We suggested that hydrogen peroxide as an electrolysis medium for hydrogen production and therefore as a hydrogen carrier, demonstrating that the electrocatalyst guaranteed high hydrogen production rate by hydrogen peroxide splitting. The electron deficiency of cobalt allows CoN4 to have the highly HPOR-active monovalent oxidation state and facilitates HPOR at small overpotentials range around the onset potential. The strong interaction between the electron-deficient cobalt and oxygen of peroxide adsorbates in Co─OOH- encourages an axially coordinated cobalt oxo complex (O═CoN4 ) to form, the O═CoN4 facilitating the HPOR efficiently at high overpotentials. Low-voltage oxygen evolution reaction guaranteeing low-voltage hydrogen production is successfully demonstrated in the presence of the metal-oxo complex having electron-deficient CoN4 . Hydrogen production by 391 mA cm-2 at 1 V and 870 mA cm-2 at 1.5 V is obtained. Also, the techno-economic benefit of hydrogen peroxide as a hydrogen carrier is evaluated by comparing hydrogen peroxide with other hydrogen carriers such as ammonia and liquid organic hydrogen carriers.

19.
Small ; 19(43): e2302722, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37376876

RESUMO

Tailoring the Li+ microenvironment is crucial for achieving fast ionic transfer and a mechanically reinforced solid-electrolyte interphase (SEI), which administers the stable cycling of Li-metal batteries (LMBs). Apart from traditional salt/solvent compositional tuning, this study presents the simultaneous modulation of Li+ transport and SEI chemistry using a citric acid (CA)-modified silica-based colloidal electrolyte (C-SCE). CA-tethered silica (CA-SiO2 ) can render more active sites for attracting complex anions, leading to further dissociation of Li+ from the anions, resulting in a high Li+ transference number (≈0.75). Intermolecular hydrogen bonds between solvent molecules and CA-SiO2 and their migration also act as nano-carrier for delivering additives and anions toward the Li surface, reinforcing the SEI via the co-implantation of SiO2 and fluorinated components. Notably, C-SCE demonstrated Li dendrite suppression and improved cycling stability of LMBs compared with the CA-free SiO2 colloidal electrolyte, hinting that the surface properties of the nanoparticles have a huge impact on the dendrite-inhibiting role of nano colloidal electrolytes.

20.
Small ; 19(5): e2205229, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36449654

RESUMO

III-Nitride semiconductor-based quantum dots (QDs) play an essential role in solid-state quantum light sources because of their potential for room-temperature operation. However, undesired background emission from the surroundings deteriorates single-photon purity. Moreover, spectral diffusion causes inhomogeneous broadening and limits the applications of QDs in quantum photonic technologies. To overcome these obstacles, it is demonstrated that directly pumping carriers to the excited state of the QD reduces the number of carriers generated in the vicinities. The polarization-controlled quasi-resonant excitation is applied to InGaN QDs embedded in GaN nanowire. To analyze the different excitation mechanisms, polarization-resolved absorptions are investigated under the above-barrier bandgap, below-barrier bandgap, and quasi-resonant excitation conditions. By employing polarization-controlled quasi-resonant excitation, the linewidth is reduced from 353 to 272 µeV, and the second-order correlation value is improved from 0.470 to 0.231. Therefore, a greater single-photon purity can be obtained at higher temperatures due to decreased linewidth and background emission.

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