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1.
Life Sci Alliance ; 7(6)2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38570188

RESUMO

Mistargeting of secretory proteins in the cytosol can trigger their aggregation and subsequent proteostasis decline. We have identified a VCP/p97-dependent pathway that directs non-ER-imported prion protein (PrP) into the nucleus to prevent the formation of toxic aggregates in the cytosol. Upon impaired translocation into the ER, PrP interacts with VCP/p97, which facilitates nuclear import mediated by importin-ß. Notably, the cytosolic interaction of PrP with VCP/p97 and its nuclear import are independent of ubiquitination. In vitro experiments revealed that VCP/p97 binds non-ubiquitinated PrP and prevents its aggregation. Inhibiting binding of PrP to VCP/p97, or transient proteotoxic stress, promotes the formation of self-perpetuating and partially proteinase resistant PrP aggregates in the cytosol, which compromised cellular proteostasis and disrupted further nuclear targeting of PrP. In the nucleus, RNAs keep PrP in a soluble and non-toxic conformation. Our study revealed a novel ubiquitin-independent role of VCP/p97 in the nuclear targeting of non-imported secretory proteins and highlights the impact of the chemical milieu in triggering protein misfolding.


Assuntos
Proteínas Priônicas , Príons , Proteínas Priônicas/metabolismo , Proteína com Valosina/metabolismo , Adenosina Trifosfatases/metabolismo , Proteostase , Ubiquitina/metabolismo , Príons/metabolismo
2.
Proc Natl Acad Sci U S A ; 121(15): e2322563121, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38557192

RESUMO

Mammalian switch/sucrose nonfermentable (mSWI/SNF) ATPase degraders have been shown to be effective in enhancer-driven cancers by functioning to impede oncogenic transcription factor chromatin accessibility. Here, we developed AU-24118, an orally bioavailable proteolysis-targeting chimera (PROTAC) degrader of mSWI/SNF ATPases (SMARCA2 and SMARCA4) and PBRM1. AU-24118 demonstrated tumor regression in a model of castration-resistant prostate cancer (CRPC) which was further enhanced with combination enzalutamide treatment, a standard of care androgen receptor (AR) antagonist used in CRPC patients. Importantly, AU-24118 exhibited favorable pharmacokinetic profiles in preclinical analyses in mice and rats, and further toxicity testing in mice showed a favorable safety profile. As acquired resistance is common with targeted cancer therapeutics, experiments were designed to explore potential mechanisms of resistance that may arise with long-term mSWI/SNF ATPase PROTAC treatment. Prostate cancer cell lines exposed to long-term treatment with high doses of a mSWI/SNF ATPase degrader developed SMARCA4 bromodomain mutations and ABCB1 (ATP binding cassette subfamily B member 1) overexpression as acquired mechanisms of resistance. Intriguingly, while SMARCA4 mutations provided specific resistance to mSWI/SNF degraders, ABCB1 overexpression provided broader resistance to other potent PROTAC degraders targeting bromodomain-containing protein 4 and AR. The ABCB1 inhibitor, zosuquidar, reversed resistance to all three PROTAC degraders tested. Combined, these findings position mSWI/SNF degraders for clinical translation for patients with enhancer-driven cancers and define strategies to overcome resistance mechanisms that may arise.


Assuntos
Adenosina Trifosfatases , Neoplasias de Próstata Resistentes à Castração , Masculino , Humanos , Ratos , Camundongos , Animais , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/genética , Linhagem Celular , Cromatina , Mamíferos/genética , Antagonistas de Receptores de Andrógenos , DNA Helicases/genética , Proteínas Nucleares/genética , Fatores de Transcrição/genética
3.
Technol Cancer Res Treat ; 23: 15330338241241935, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38564315

RESUMO

Hepatocellular carcinoma (HCC), partly because of its complexity and high heterogeneity, has a poor prognosis and an extremely high mortality rate. In this study, mRNA sequencing expression profiles and relevant clinical data of HCC patients were gathered from different public databases. Kaplan-Meier survival curves as well as ROC curves validated that OLA1|CLEC3B was an independent predictor with better predictive capability of HCC prognosis compared to OLA1 and CLEC3B separately. Further, the cell transfection experiment verified that knockdown of OLA1 inhibited cell proliferation, facilitated apoptosis, and improved sensitivity of HCC cells to gemcitabine. In this study, the prognostic model of HCC composed of OLA1/CLEC3B genes was constructed and verified, and the prediction ability was favorable. A higher level of OLA1 along with a lower level of CEC3B is a sign of poor prognosis in HCC. We revealed a novel gene pair OLA1|CLEC3B overexpressed in HCC patients, which may serve as a promising independent predictor of HCC survival and an approach for innovative diagnostic and therapeutic strategies.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/genética , Prognóstico , Neoplasias Hepáticas/genética , Apoptose/genética , Proliferação de Células/genética , Adenosina Trifosfatases , Proteínas de Ligação ao GTP
4.
Protein Sci ; 33(5): e4981, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38591662

RESUMO

Translesion DNA synthesis pathways are necessary to ensure bacterial replication in the presence of DNA damage. Translesion DNA synthesis carried out by the PolV mutasome is well-studied in Escherichia coli, but ~one third of bacteria use a functionally homologous protein complex, consisting of ImuA, ImuB, and ImuC (also called DnaE2). Numerous in vivo studies have shown that all three proteins are required for translesion DNA synthesis and that ImuC is the error-prone polymerase, but the roles of ImuA and ImuB are unclear. Here we carry out biochemical characterization of ImuA and a truncation of ImuB from Myxococcus xanthus. We find that ImuA is an ATPase, with ATPase activity enhanced in the presence of DNA. The ATPase activity is likely regulated by the C-terminus, as loss of the ImuA C-terminus results in DNA-independent ATP hydrolysis. We also find that ImuA binds a variety of DNA substrates, with DNA binding affinity affected by the addition of ADP or adenylyl-imidodiphosphate. An ImuB truncation also binds DNA, with lower affinity than ImuA. In the absence of DNA, ImuA directly binds ImuB with moderate affinity. Finally, we show that ImuA and ImuB self-interact, but that ImuA is predominantly a monomer, while truncated ImuB is a trimer in vitro. Together, with our findings and the current literature in the field, we suggest a model for translesion DNA synthesis, where a trimeric ImuB would provide sufficient binding sites for DNA, the ß-clamp, ImuC, and ImuA, and where ImuA ATPase activity may regulate assembly and disassembly of the translesion DNA synthesis complex.


Assuntos
Myxococcus xanthus , Myxococcus xanthus/genética , Myxococcus xanthus/metabolismo , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Proteínas de Bactérias/química , Escherichia coli/genética , Escherichia coli/metabolismo , DNA/genética , Replicação do DNA
5.
An Acad Bras Cienc ; 96(1): e20230971, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38597493

RESUMO

Paraquat (1,1'-dimethyl-4,4'-bipyridyl dichloride) is an herbicide widely used worldwide and officially banned in Brazil in 2020. Kidney lesions frequently occur, leading to acute kidney injury (AKI) due to exacerbated reactive O2 species (ROS) production. However, the consequences of ROS exposure on ionic transport and the regulator local renin-angiotensin-aldosterone system (RAAS) still need to be elucidated at a molecular level. This study evaluated how ROS acutely influences Na+-transporting ATPases and the renal RAAS. Adult male Wistar rats received paraquat (20 mg/kg; ip). After 24 h, we observed body weight loss and elevation of urinary flow and serum creatinine. In the renal cortex, paraquat increased ROS levels, NADPH oxidase and (Na++K+)ATPase activities, angiotensin II-type 1 receptors, tumor necrosis factor-α (TNF-α), and interleukin-6. In the medulla, paraquat increased ROS levels and NADPH oxidase activity but inhibited (Na++K+)ATPase. Paraquat induced opposite effects on the ouabain-resistant Na+-ATPase in the cortex (decrease) and medulla (increase). These alterations, except for increased serum creatinine and renal levels of TNF-α and interleukin-6, were prevented by 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (tempol; 1 mmol/L in drinking water), a stable antioxidant. In summary, after paraquat poisoning, ROS production culminated with impaired medullary function, urinary fluid loss, and disruption of Na+-transporting ATPases and angiotensin II signaling.


Assuntos
Paraquat , Sistema Renina-Angiotensina , Ratos , Animais , Masculino , Espécies Reativas de Oxigênio/metabolismo , Paraquat/metabolismo , Paraquat/farmacologia , Angiotensina II/metabolismo , Angiotensina II/farmacologia , Creatinina/metabolismo , Creatinina/urina , Interleucina-6 , Fator de Necrose Tumoral alfa/metabolismo , Ratos Wistar , Rim , Adenosina Trifosfatases/metabolismo , Adenosina Trifosfatases/farmacologia , Sódio/metabolismo , Sódio/farmacologia , NADPH Oxidases/metabolismo , NADPH Oxidases/farmacologia
6.
Int J Mol Sci ; 25(5)2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38473983

RESUMO

Asians have a higher carrier rate of pulmonary arterial hypertension (PAH)-related genetic variants than Caucasians do. This study aimed to identify PAH-related genetic variants using whole exome sequencing (WES) in Asian idiopathic and heritable PAH cohorts. A WES library was constructed, and candidate variants were further validated by polymerase chain reaction and Sanger sequencing in the PAH cohort. In a total of 69 patients, the highest incidence of variants was found in the BMPR2, ATP13A3, and GDF2 genes. Regarding the BMPR2 gene variants, there were two nonsense variants (c.994C>T, p. Arg332*; c.1750C>T, p. Arg584*), one missense variant (c.1478C>T, p. Thr493Ile), and one novel in-frame deletion variant (c.877_888del, p. Leu293_Ser296del). Regarding the GDF2 variants, there was one likely pathogenic nonsense variant (c.259C>T, p. Gln87*) and two missense variants (c.1207G>A, p. Val403Ile; c.38T>C, p. Leu13Pro). The BMPR2 and GDF2 variant subgroups had worse hemodynamics. Moreover, the GDF2 variant patients were younger and had a significantly lower GDF2 value (135.6 ± 36.2 pg/mL, p = 0.002) in comparison to the value in the non-BMPR2/non-GDF2 mutant group (267.8 ± 185.8 pg/mL). The BMPR2 variant carriers had worse hemodynamics compared to the patients with the non-BMPR2/non-GDF2 mutant group. Moreover, there was a significantly lower GDF2 value in the GDF2 variant carriers compared to the control group. GDF2 may be a protective or corrected modifier in certain genetic backgrounds.


Assuntos
Hipertensão Arterial Pulmonar , Humanos , Hipertensão Arterial Pulmonar/genética , Hipertensão Pulmonar Primária Familiar/genética , Mutação de Sentido Incorreto , Hemodinâmica , Deleção de Sequência , Receptores de Proteínas Morfogenéticas Ósseas Tipo II/genética , Mutação , Adenosina Trifosfatases/genética , Proteínas de Membrana Transportadoras/genética , Fator 2 de Diferenciação de Crescimento/genética
7.
J Cell Biol ; 223(5)2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38448163

RESUMO

Endoplasmic reticulum (ER) proteins are degraded by proteasomes in the cytosol through ER-associated degradation (ERAD). This process involves the retrotranslocation of substrates across the ER membrane, their ubiquitination, and membrane extraction by the Cdc48/Npl4/Ufd1 ATPase complex prior to delivery to proteasomes for degradation. How the presence of a folded luminal domain affects substrate retrotranslocation and this event is coordinated with subsequent ERAD steps remains unknown. Here, using a model substrate with a folded luminal domain, we showed that Cdc48 ATPase activity is sufficient to drive substrate retrotranslocation independently of ERAD membrane components. However, the complete degradation of the folded luminal domain required substrate-tight coupling of retrotranslocation and proteasomal degradation, which was ensured by the derlin Dfm1. Mutations in Dfm1 intramembrane rhomboid-like or cytosolic Cdc48-binding regions resulted in partial degradation of the substrate with accumulation of its folded domain. Our study revealed Dfm1 as a critical regulator of Cdc48-driven retrotranslocation and highlights the importance of coordinating substrate retrotranslocation and degradation during ERAD.


Assuntos
Retículo Endoplasmático , Proteínas de Membrana , Complexo de Endopeptidases do Proteassoma , Proteínas de Saccharomyces cerevisiae , Adenosina Trifosfatases/genética , Citosol , Retículo Endoplasmático/metabolismo , Degradação Associada com o Retículo Endoplasmático , Complexo de Endopeptidases do Proteassoma/metabolismo , Domínios Proteicos , Proteínas de Membrana/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo
8.
Protein Sci ; 33(4): e4948, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38501485

RESUMO

Increasing antimicrobial drug resistance represents a global existential threat. Infection is a particular problem in immunocompromised individuals, such as patients undergoing cancer chemotherapy, due to the targeting of rapidly dividing cells by antineoplastic agents. We recently developed a strategy that targets bacterial nucleotide excision DNA repair (NER) to identify compounds that act as antimicrobial sensitizers specific for patients undergoing cancer chemotherapy. Building on this, we performed a virtual drug screening of a ~120,000 compound library against the key NER protein UvrA. From this, numerous target compounds were identified and of those a candidate compound, Bemcentinib (R428), showed a strong affinity toward UvrA. This NER protein possesses four ATPase sites in its dimeric state, and we found that Bemcentinib could inhibit UvrA's ATPase activity by ~90% and also impair its ability to bind DNA. As a result, Bemcentinib strongly diminishes NER's ability to repair DNA in vitro. To provide a measure of in vivo activity we discovered that the growth of Escherichia coli MG1655 was significantly inhibited when Bemcentinib was combined with the DNA damaging agent 4-NQO, which is analogous to UV. Using the clinically relevant DNA-damaging antineoplastic cisplatin in combination with Bemcentinib against the urological sepsis-causing E. coli strain EC958 caused complete growth inhibition. This study offers a novel approach for the potential development of new compounds for use as adjuvants in antineoplastic therapy.


Assuntos
Antineoplásicos , Benzocicloeptenos , Proteínas de Escherichia coli , Neoplasias , Triazóis , Humanos , Escherichia coli/genética , Escherichia coli/metabolismo , Reparo do DNA , Dano ao DNA , Antineoplásicos/farmacologia , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , DNA/metabolismo , Adenosina Trifosfatases/metabolismo
9.
J Extracell Vesicles ; 13(4): e12426, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38532609

RESUMO

Besides participating in diverse pathological and physiological processes, extracellular vesicles (EVs) are also excellent drug-delivery vehicles. However, clinical drugs modulating EV levels are still lacking. Here, we show that proton pump inhibitors (PPIs) reduce EVs by enhancing macropinocytosis-mediated EV uptake. PPIs accelerate intestinal cell endocytosis of autocrine immunosuppressive EVs through macropinocytosis, thereby aggravating inflammatory bowel disease. PPI-induced macropinocytosis facilitates the clearance of immunosuppressive EVs from tumour cells, improving antitumor immunity. PPI-induced macropinocytosis also increases doxorubicin and antisense oligonucleotides of microRNA-155 delivery efficiency by EVs, leading to enhanced therapeutic effects of drug-loaded EVs on tumours and acute liver failure. Mechanistically, PPIs reduce cytosolic pH, promote ATP6V1A (v-ATPase subunit) disassembly from the vacuolar membrane and enhance the assembly of plasma membrane v-ATPases, thereby inducing macropinocytosis. Altogether, our results reveal a mechanism for macropinocytic regulation and PPIs as potential modulators of EV levels, thus regulating their functions.


Assuntos
Vesículas Extracelulares , Inibidores da Bomba de Prótons , Endocitose , Pinocitose , Adenosina Trifosfatases
10.
Artigo em Inglês | MEDLINE | ID: mdl-38458419

RESUMO

Insect Malpighian tubules contribute to Ca2+ homeostasis via Ca2+ storage in intracellular compartments, Ca2+ secretion into the tubule lumen, and Ca2+ reabsorption into the hemolymph. A plasma membrane Ca2+-ATPase (PMCA) is hypothesized to be a Ca2+-transporter involved in renal Ca2+ transport of insects, however few studies have investigated its immunochemical expression in Malpighian tubules. Here we characterized the abundance and localization of PMCA-like immunoreactivity in Malpighian tubules of adult female mosquitoes Aedes aegypti using an antibody against Drosophila melanogaster PMCA. Western blotting revealed expression of a relatively abundant 109 kDa isoform and a relatively sparse 115 kDa isoform. Feeding mosquitoes 10% sucrose with 50 mM CaCl2 for 7 days did not affect PMCA immunoreactivity. However, at 24, 48, and 96 h post-blood feeding (PBF), the relative abundance of the 109 kDa isoform decreased while that of the 115 kDa isoform increased. Immunolabeling of Malpighian tubules revealed PMCA-like immunoreactivity in both principal and stellate cells; principal cell labeling was intracellular, whereas stellate cell labeling was along the basal membrane. Blood feeding enhanced immunolabeling of PMCA in stellate cells but weakened that in principal cells. Moreover, a unique apicolateral pattern of PMCA-like immunolabeling occurred in principal cells of the proximal segment at 24 h PBF, suggesting potential trafficking to septate junctions. Our results suggest PMCA isoforms are differentially expressed and localized in mosquito Malpighian tubules where they contribute to redistributing tubule Ca2+ during blood meal processing.


Assuntos
Aedes , Feminino , Animais , Aedes/metabolismo , Adenosina Trifosfatases/metabolismo , Túbulos de Malpighi/metabolismo , Cálcio da Dieta/metabolismo , Cálcio da Dieta/farmacologia , Drosophila melanogaster , Membrana Celular , Isoformas de Proteínas/metabolismo
11.
Int J Mol Sci ; 25(6)2024 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-38542345

RESUMO

Single-particle cryo-electron microscopy (cryo-EM) has been shown to be effective in defining the structure of macromolecules, including protein complexes. Complexes adopt different conformations and compositions to perform their biological functions. In cryo-EM, the protein complexes are observed in solution, enabling the recording of images of the protein in multiple conformations. Various methods exist for capturing the conformational variability through analysis of cryo-EM data. Here, we analyzed the conformational variability in the hexameric AAA + ATPase p97, a complex with a six-fold rotational symmetric core surrounded by six flexible N-domains. We compared the performance of discrete classification methods with our recently developed method, MDSPACE, which uses 3D-to-2D flexible fitting of an atomic structure to images based on molecular dynamics (MD) simulations. Our analysis detected a novel conformation adopted by approximately 2% of the particles in the dataset and determined that the N-domains of p97 sway by up to 60° around a central position. This study demonstrates the application of MDSPACE in analyzing the continuous conformational changes in partially symmetrical protein complexes, systems notoriously difficult to analyze due to the alignment errors caused by their partial symmetry.


Assuntos
Adenosina Trifosfatases , ATPases Associadas a Diversas Atividades Celulares/metabolismo , Estrutura Terciária de Proteína , Modelos Moleculares , Microscopia Crioeletrônica/métodos , Adenosina Trifosfatases/metabolismo
12.
Biol Open ; 13(4)2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38526189

RESUMO

CENP-A determines the identity of the centromere. Because the position and size of the centromere and its number per chromosome must be maintained, the distribution of CENP-A is strictly regulated. In this study, we have aimed to understand mechanisms to regulate the distribution of CENP-A (Cnp1SP) in fission yeast. A mutant of the ufd1+ gene (ufd1-73) encoding a cofactor of Cdc48 ATPase is sensitive to Cnp1 expressed at a high level and allows mislocalization of Cnp1. The level of Cnp1 in centromeric chromatin is increased in the ufd1-73 mutant even when Cnp1 is expressed at a normal level. A preexisting mutant of the cdc48+ gene (cdc48-353) phenocopies the ufd1-73 mutant. We have also shown that Cdc48 and Ufd1 proteins interact physically with centromeric chromatin. Finally, Cdc48 ATPase with Ufd1 artificially recruited to the centromere of a mini-chromosome (Ch16) induce a loss of Cnp1 from Ch16, leading to an increased rate of chromosome loss. It appears that Cdc48 ATPase, together with its cofactor Ufd1 remove excess Cnp1 from chromatin, likely in a direct manner. This mechanism may play a role in centromere disassembly, a process to eliminate Cnp1 to inactivate the kinetochore function during development, differentiation, and stress response.


Assuntos
Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces , Cromatina/genética , Cromatina/metabolismo , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Proteína Centromérica A/genética , Proteína Centromérica A/metabolismo , Histonas/metabolismo , Proteínas de Schizosaccharomyces pombe/genética , Proteínas de Schizosaccharomyces pombe/metabolismo , Proteínas Cromossômicas não Histona/genética , Proteínas Cromossômicas não Histona/metabolismo , Centrômero/genética , Centrômero/metabolismo , Adenosina Trifosfatases/metabolismo , Extratos Vegetais/metabolismo
13.
Mol Cell ; 84(7): 1321-1337.e11, 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38513662

RESUMO

Intracellular Mg2+ (iMg2+) is bound with phosphometabolites, nucleic acids, and proteins in eukaryotes. Little is known about the intracellular compartmentalization and molecular details of Mg2+ transport into/from cellular organelles such as the endoplasmic reticulum (ER). We found that the ER is a major iMg2+ compartment refilled by a largely uncharacterized ER-localized protein, TMEM94. Conventional and AlphaFold2 predictions suggest that ERMA (TMEM94) is a multi-pass transmembrane protein with large cytosolic headpiece actuator, nucleotide, and phosphorylation domains, analogous to P-type ATPases. However, ERMA uniquely combines a P-type ATPase domain and a GMN motif for ERMg2+ uptake. Experiments reveal that a tyrosine residue is crucial for Mg2+ binding and activity in a mechanism conserved in both prokaryotic (mgtB and mgtA) and eukaryotic Mg2+ ATPases. Cardiac dysfunction by haploinsufficiency, abnormal Ca2+ cycling in mouse Erma+/- cardiomyocytes, and ERMA mRNA silencing in human iPSC-cardiomyocytes collectively define ERMA as an essential component of ERMg2+ uptake in eukaryotes.


Assuntos
Adenosina Trifosfatases , ATPases do Tipo-P , Animais , Camundongos , Humanos , Adenosina Trifosfatases/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Retículo Endoplasmático/genética , Retículo Endoplasmático/metabolismo , Transporte Biológico , ATPases do Tipo-P/metabolismo , Cálcio/metabolismo , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático
14.
Nat Commun ; 15(1): 2716, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38548759

RESUMO

Neural stem and progenitor cell (NSPC) maintenance is essential for ensuring that organisms are born with proper brain volumes and head sizes. Microcephaly is a disorder in which babies are born with significantly smaller head sizes and cortical volumes. Mutations in subunits of the DNA organizing complex condensin have been identified in microcephaly patients. However, the molecular mechanisms by which condensin insufficiency causes microcephaly remain elusive. We previously identified conserved roles for condensins in repression of retrotransposable elements (RTEs). Here, we show that condensin subunit knockdown in NSPCs of the Drosophila larval central brain increases RTE expression and mobility which causes cell death, and significantly decreases adult head sizes and brain volumes. These findings suggest that unrestricted RTE expression and activity may lead to improper brain development in condensin insufficient organisms, and lay the foundation for future exploration of causative roles for RTEs in other microcephaly models.


Assuntos
Adenosina Trifosfatases , Drosophila melanogaster , Microcefalia , Complexos Multiproteicos , Animais , Humanos , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Microcefalia/genética , Proteínas de Ligação a DNA/metabolismo , Drosophila/genética , Encéfalo/metabolismo
15.
Biomaterials ; 307: 122523, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38432004

RESUMO

Anticancer nanomedicines used for ferroptosis therapy generally rely on the direct delivery of Fenton catalysts to drive lipid peroxidation in cancer cells. However, the therapeutic efficacy is limited by the ferroptosis resistance caused by the intracellular anti-ferroptotic signals. Herein, we report the intrinsic ATPase-mimicking activity of a vanadium carbide MXene nanozyme (PVCMs) to pharmacologically modulate the nuclear factor erythroid 2-related factor 2 (Nrf2) program, which is the master anti-ferroptotic mediator in the ironclad defense system in triple-negative breast cancer (TNBC) cells. The PVCMs perform high ATPase-like activity that can effectively and selectively catalyze the dephosphorylation of ATP to generate ADP. Through a cascade mechanism initiated by falling energy status, PVCMs can powerfully hinder the Nrf2 program to selectively drive ferroptosis in TNBC cells in response to PVCMs-induced glutathione depletion. This study provides a paradigm for the use of pharmacologically active nanozymes to moderate specific cellular signals and elicit desirable pharmacological activities for therapeutic applications.


Assuntos
Ferroptose , Nitritos , Elementos de Transição , Neoplasias de Mama Triplo Negativas , Humanos , Adenosina Trifosfatases , Fator 2 Relacionado a NF-E2 , Neoplasias de Mama Triplo Negativas/tratamento farmacológico
16.
Cell Rep ; 43(3): 113901, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38446663

RESUMO

Condensin shapes mitotic chromosomes by folding chromatin into loops, but whether it does so by DNA-loop extrusion remains speculative. Although loop-extruding cohesin is stalled by transcription, the impact of transcription on condensin, which is enriched at highly expressed genes in many species, remains unclear. Using degrons of Rpb1 or the torpedo nuclease Dhp1XRN2 to either deplete or displace RNAPII on chromatin in fission yeast metaphase cells, we show that RNAPII does not load condensin on DNA. Instead, RNAPII retains condensin in cis and hinders its ability to fold mitotic chromatin and to support chromosome segregation, consistent with the stalling of a loop extruder. Transcription termination by Dhp1 limits such a hindrance. Our results shed light on the integrated functioning of condensin, and we argue that a tight control of transcription underlies mitotic chromosome assembly by loop-extruding condensin.


Assuntos
Adenosina Trifosfatases , Segregação de Cromossomos , Complexos Multiproteicos , Schizosaccharomyces , Proteínas de Ligação a DNA/genética , Cromatina , Cromossomos , DNA , Schizosaccharomyces/genética , RNA Polimerase II/genética , Mitose , Proteínas de Ciclo Celular/genética
17.
Sci Rep ; 14(1): 5237, 2024 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-38433281

RESUMO

Inflammation is implicated as a cause in many diseases. Most of the anti-inflammatory agents in use are synthetic and there is an unmet need for natural substance-derived anti-inflammatory agents with minimal side effects. Aiouea padiformis belongs to the Lauraceae family and is primarily found in tropical regions. While some members of the Aiouea genus are known to possess anti-inflammatory properties, the anti-inflammatory properties of Aiouea padiformis extract (AP) have not been investigated. In this study, we aimed to examine the anti-inflammatory function of AP through the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome and elucidate the underlying mechanisms. Treatment with AP inhibited the secretion of interleukin-1 beta (IL-1ß) mediated by NLRP3 inflammasome in J774A.1 and THP-1 cells without affecting the viability. In addition, AP treatment did not influence NF-κB signaling, potassium efflux, or intracellular reactive oxygen species (ROS) production-all of which are associated with NLRP3 inflammasome activation. However, intriguingly, AP treatment significantly reduced the ATPase activity of NLRP3, leading to the inhibition of ASC oligomerization and speck formation. Consistent with cellular experiments, the anti-inflammatory property of AP in vivo was also evaluated using an LPS-induced inflammation model in zebrafish, demonstrating that AP hinders NLRP3 inflammasome activation.


Assuntos
Lauraceae , Proteína 3 que Contém Domínio de Pirina da Família NLR , Animais , Inflamassomos , Peixe-Zebra , Inflamação/tratamento farmacológico , Anti-Inflamatórios/farmacologia , Adenosina Trifosfatases , Extratos Vegetais/farmacologia
18.
mBio ; 15(4): e0003124, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38501868

RESUMO

The Clp protease system is important for maintaining proteostasis in bacteria. It consists of ClpP serine proteases and an AAA+ Clp-ATPase such as ClpC1. The hexameric ATPase ClpC1 utilizes the energy of ATP binding and hydrolysis to engage, unfold, and translocate substrates into the proteolytic chamber of homo- or hetero-tetradecameric ClpP for degradation. The assembly between the hetero-tetradecameric ClpP1P2 chamber and the Clp-ATPases containing tandem ATPase domains from the same species has not been studied in depth. Here, we present cryo-EM structures of the substrate-bound ClpC1:shClpP1P2 from Streptomyces hawaiiensis, and shClpP1P2 in complex with ADEP1, a natural compound produced by S. hawaiiensis and known to cause over-activation and dysregulation of the ClpP proteolytic core chamber. Our structures provide detailed information on the shClpP1-shClpP2, shClpP2-ClpC1, and ADEP1-shClpP1/P2 interactions, reveal conformational transition of ClpC1 during the substrate translocation, and capture a rotational ATP hydrolysis mechanism likely dominated by the D1 ATPase activity of chaperones.IMPORTANCEThe Clp-dependent proteolysis plays an important role in bacterial homeostasis and pathogenesis. The ClpP protease system is an effective drug target for antibacterial therapy. Streptomyces hawaiiensis can produce a class of potent acyldepsipeptide antibiotics such as ADEP1, which could affect the ClpP protease activity. Although S. hawaiiensis hosts one of the most intricate ClpP systems in nature, very little was known about its Clp protease mechanism and the impact of ADEP molecules on ClpP. The significance of our research is in dissecting the functional mechanism of the assembled Clp degradation machinery, as well as the interaction between ADEP1 and the ClpP proteolytic chamber, by solving high-resolution structures of the substrate-bound Clp system in S. hawaiiensis. The findings shed light on our understanding of the Clp-dependent proteolysis in bacteria, which will enhance the development of antimicrobial drugs targeting the Clp protease system, and help fighting against bacterial multidrug resistance.


Assuntos
Adenosina Trifosfatases , Endopeptidase Clp , Streptomyces , Endopeptidase Clp/genética , Endopeptidase Clp/metabolismo , Proteólise , Adenosina Trifosfatases/metabolismo , ATPases Associadas a Diversas Atividades Celulares/metabolismo , Peptídeo Hidrolases/metabolismo , Trifosfato de Adenosina/metabolismo
19.
J Proteome Res ; 23(4): 1174-1187, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38427982

RESUMO

Protein homeostasis is essential for cyanobacteria to maintain proper cellular function under adverse and fluctuating conditions. The AAA+ superfamily of proteolytic complexes in cyanobacteria plays a critical role in this process, including ClpXP, which comprises a hexameric ATPase ClpX and a tetradecameric peptidase ClpP. Despite the physiological effects of ClpX on growth and photosynthesis, its potential substrates and underlying mechanisms in cyanobacteria remain unknown. In this study, we employed a streptavidin-biotin affinity pull-down assay coupled with label-free proteome quantitation to analyze the interactome of ClpX in the model cyanobacterium Synechocystis sp. PCC 6803 (hereafter Synechocystis). We identified 503 proteins as potential ClpX-binding targets, many of which had novel interactions. These ClpX-binding targets were found to be involved in various biological processes, with particular enrichment in metabolic processes and photosynthesis. Using protein-protein docking, GST pull-down, and biolayer interferometry assays, we confirmed the direct association of ClpX with the photosynthetic proteins, ferredoxin-NADP+ oxidoreductase (FNR) and phycocyanin subunit (CpcA). Subsequent functional investigations revealed that ClpX participates in the maintenance of FNR homeostasis and functionality in Synechocystis grown under different light conditions. Overall, our study provides a comprehensive understanding of the extensive functions regulated by ClpX in cyanobacteria to maintain protein homeostasis and adapt to environmental challenges.


Assuntos
Fotossíntese , Synechocystis , Fotossíntese/genética , Synechocystis/genética , Synechocystis/metabolismo , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Ficocianina/metabolismo
20.
J Phys Chem Lett ; 15(13): 3502-3508, 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38517341

RESUMO

RNA ATPases/helicases remodel substrate RNA-protein complexes in distinct ways. The different RNA ATPases/helicases, taking part in the spliceosome complex, reshape the RNA/RNA-protein contacts to enable premature-mRNA splicing. Among them, the bad response to refrigeration 2 (Brr2) helicase promotes U4/U6 small nuclear (sn)RNA unwinding via ATP-driven translocation of the U4 snRNA strand, thus playing a pivotal role during the activation, catalytic, and disassembly phases of splicing. The plastic Brr2 architecture consists of an enzymatically active N-terminal cassette (N-cassette) and a structurally similar but inactive C-terminal cassette (C-cassette). The C-cassette, along with other allosteric effectors and regulators, tightly and timely controls Brr2's function via an elusive mechanism. Here, microsecond-long molecular dynamics simulations, dynamical network theory, and community network analysis are combined to elucidate how allosteric effectors/regulators modulate the Brr2 function. We unexpectedly reveal that U4 snRNA itself acts as an allosteric regulator, amplifying the cross-talk of distal Brr2 domains and triggering a conformational reorganization of the protein. Our findings offer fundamental understanding into Brr2's mechanism of action and broaden our knowledge on the sophisticated regulatory mechanisms by which spliceosome ATPases/helicases control gene expression. This includes their allosteric regulation exerted by client RNA strands, a mechanism that may be broadly applicable to other RNA-dependent ATPases/helicases.


Assuntos
Ribonucleoproteínas Nucleares Pequenas , Spliceossomos , Humanos , Adenosina Trifosfatases/metabolismo , Ribonucleoproteína Nuclear Pequena U4-U6/química , Ribonucleoproteína Nuclear Pequena U4-U6/genética , Ribonucleoproteína Nuclear Pequena U4-U6/metabolismo , RNA/metabolismo , RNA Helicases/química , RNA Helicases/genética , RNA Helicases/metabolismo , Spliceossomos/genética , Spliceossomos/metabolismo , Ribonucleoproteínas Nucleares Pequenas/metabolismo
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