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1.
Commun Biol ; 5(1): 780, 2022 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-35918402

RESUMO

Glioblastoma multiforme (GBM) is the most frequent and aggressive form of primary brain tumor in the adult population; its high recurrence rate and resistance to current therapeutics urgently demand a better therapy. Regulation of protein stability by the ubiquitin proteasome system (UPS) represents an important control mechanism of cell growth. UPS deregulation is mechanistically linked to the development and progression of a variety of human cancers, including GBM. Thus, the UPS represents a potentially valuable target for GBM treatment. Using an integrated approach that includes proteomics, transcriptomics and metabolic profiling, we identify praja2, a RING E3 ubiquitin ligase, as the key component of a signaling network that regulates GBM cell growth and metabolism. Praja2 is preferentially expressed in primary GBM lesions expressing the wild-type isocitrate dehydrogenase 1 gene (IDH1). Mechanistically, we found that praja2 ubiquitylates and degrades the kinase suppressor of Ras 2 (KSR2). As a consequence, praja2 restrains the activity of downstream AMP-dependent protein kinase in GBM cells and attenuates the oxidative metabolism. Delivery in the brain of siRNA targeting praja2 by transferrin-targeted self-assembling nanoparticles (SANPs) prevented KSR2 degradation and inhibited GBM growth, reducing the size of the tumor and prolonging the survival rate of treated mice. These data identify praja2 as an essential regulator of cancer cell metabolism, and as a potential therapeutic target to suppress GBM growth.


Assuntos
Neoplasias Encefálicas , Glioblastoma , Adulto , Animais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Glioblastoma/metabolismo , Humanos , Camundongos , Complexo de Endopeptidases do Proteassoma/metabolismo , Transdução de Sinais , Ubiquitina
2.
Cell Death Dis ; 13(8): 685, 2022 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-35933405

RESUMO

In view of the important roles played by Kinetochore proteins in mitosis, we believed that they may contribute to the development and progression of human cancers, which has been reported recently elsewhere. Kinetochore-associated 1 (KNTC1) participates in the segregation of sister chromatids during mitosis, the effects of which on non-small-cell lung cancer (NSCLC) remain unclear. Here, we sought to identify the biological significance of KNTC1 in NSCLC. KNTC1 protein expression in NSCLC tissues was investigated by immunohistochemistry. Lentivirus delivered short hairpin RNA (shRNA) was utilized to establish KNTC1 silence NSCLC cell lines. The effects of KNTC1 depletion on NSCLC cell proliferation, migration, apoptosis, and tumor formation were analyzed by MTT assay, wound-healing assay, transwell assay, flow cytometry assay, and in nude mouse models in vivo. After KNTC1 reduction, NSCLC cell viability, proliferation, migration, and invasion were restrained. A xenograft tumor model was also provided to demonstrate the inhibited tumorigenesis in NSCLC. In addition, the downstream mechanism analysis indicated that KNTC1 depletion was positively associated with PSMB8. The findings of the present study suggested that KNTC1 may have a pivotal role in mediating NSCLC progression and may act as a novel therapeutic target for NSCLC.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , MicroRNAs , Complexo de Endopeptidases do Proteassoma/metabolismo , RNA Longo não Codificante , Animais , Carcinoma Pulmonar de Células não Pequenas/patologia , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Pulmonares/patologia , Camundongos , MicroRNAs/genética , Proteínas Associadas aos Microtúbulos/metabolismo , RNA Longo não Codificante/genética , RNA Interferente Pequeno/genética
3.
Nat Commun ; 13(1): 4462, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35915093

RESUMO

Defects in cellular proteostasis and mitochondrial function drive many aspects of infertility, cancer, and other age-related diseases. All of these conditions rely on quiescent cells, such as oocytes and adult stem cells, that reduce their activity and remain dormant as part of their roles in tissue homeostasis, reproduction, and even cancer recurrence. Using a multi-organism approach, we show that dynamic shifts in the ubiquitin proteasome system drive mitochondrial remodeling during cellular quiescence. In contrast to the commonly held view that the ubiquitin-proteasome system (UPS) is primarily regulated by substrate ubiquitination, we find that increasing proteasome number and their recruitment to mitochondria support mitochondrial respiratory quiescence (MRQ). GSK3 triggers proteasome recruitment to the mitochondria by phosphorylating outer membrane proteins, such as VDAC, and suppressing mitochondrial fatty acid oxidation. This work defines a process that couples dynamic regulation of UPS activity to coordinated shifts in mitochondrial metabolism in fungi, Drosophila, and mammals during quiescence.


Assuntos
Complexo de Endopeptidases do Proteassoma , Ubiquitina , Animais , Quinase 3 da Glicogênio Sintase/metabolismo , Mamíferos/metabolismo , Mitocôndrias/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Ubiquitina/metabolismo , Ubiquitinação
4.
Cell Rep ; 40(6): 111175, 2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-35947953

RESUMO

Protein degradation is fundamentally important to ensure cell homeostasis. In the endoplasmic reticulum (ER), the ER-associated degradation (ERAD) pathway targets incorrectly folded and unassembled proteins for turnover by the cytoplasmic proteasome. Previously, we showed that the rhomboid protease RHBDL4, together with p97, mediates membrane protein degradation. However, whether RHBDL4 acts in concert with additional ERAD components is unclear, and its full substrate spectrum remains to be defined. Here, we show that, in addition to membrane proteins, RHBDL4 cleaves aggregation-prone luminal ERAD substrates. Since mutations of the RHBDL4 rhomboid domain led to stabilization of substrates at the cytoplasmic side, we hypothesize that, analogous to the homolog ERAD factor derlin, RHBDL4 is directly involved in substrate retrotranslocation. RHBDL4's interaction with the erlin ERAD complex and reciprocal interaction of rhomboid substrates with erlins suggest that RHBDL4 and erlins form a complex that clips substrates and thereby rescues aggregation-prone peptides in the ER from aggregation.


Assuntos
Degradação Associada com o Retículo Endoplasmático , Retículo Endoplasmático , Endopeptidases/metabolismo , Retículo Endoplasmático/metabolismo , Proteínas de Membrana/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise
5.
ACS Chem Biol ; 17(7): 1733-1744, 2022 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-35793809

RESUMO

PROteolysis TArgeting Chimeras (PROTACs) use the ubiquitin-proteasome system to degrade a protein of interest for therapeutic benefit. Advances made in targeted protein degradation technology have been remarkable, with several molecules having moved into clinical studies. However, robust routes to assess and better understand the safety risks of PROTACs need to be identified, which is an essential step toward delivering efficacious and safe compounds to patients. In this work, we used Cell Painting, an unbiased high-content imaging method, to identify phenotypic signatures of PROTACs. Chemical clustering and model prediction allowed the identification of a mitotoxicity signature that could not be expected by screening the individual PROTAC components. The data highlighted the benefit of unbiased phenotypic methods for identifying toxic signatures and the potential to impact drug design.


Assuntos
Quimera , Ensaios de Triagem em Larga Escala , Quimera/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intercelular , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise , Ubiquitina-Proteína Ligases/metabolismo
6.
PLoS Pathog ; 18(7): e1010660, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35816513

RESUMO

Coxiella burnetii is the etiological agent of the zoonotic disease Q fever, which is featured by its ability to replicate in acid vacuoles resembling the lysosomal network. One key virulence determinant of C. burnetii is the Dot/Icm system that transfers more than 150 effector proteins into host cells. These effectors function to construct the lysosome-like compartment permissive for bacterial replication, but the functions of most of these effectors remain elusive. In this study, we used an affinity tag purification mass spectrometry (AP-MS) approach to generate a C. burnetii-human protein-protein interaction (PPI) map involving 53 C. burnetii effectors and 3480 host proteins. This PPI map revealed that the C. burnetii effector CBU0425 (designated CirB) interacts with most subunits of the 20S core proteasome. We found that ectopically expressed CirB inhibits hydrolytic activity of the proteasome. In addition, overexpression of CirB in C. burnetii caused dramatic inhibition of proteasome activity in host cells, while knocking down CirB expression alleviated such inhibitory effects. Moreover, we showed that a region of CirB that spans residues 91-120 binds to the proteasome subunit PSMB5 (beta 5). Finally, PSMB5 knockdown promotes C. burnetii virulence, highlighting the importance of proteasome activity modulation during the course of C. burnetii infection.


Assuntos
Coxiella burnetii , Febre Q , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Interações Hospedeiro-Patógeno , Humanos , Complexo de Endopeptidases do Proteassoma/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Mapas de Interação de Proteínas , Febre Q/metabolismo , Vacúolos/metabolismo
7.
Proc Natl Acad Sci U S A ; 119(29): e2119736119, 2022 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-35858315

RESUMO

In the current era of T cell-based immunotherapies, it is crucial to understand which types of MHC-presented T cell antigens are produced by tumor cells. In addition to linear peptide antigens, chimeric peptides are generated through proteasome-catalyzed peptide splicing (PCPS). Whether such spliced peptides are abundantly presented by MHC is highly disputed because of disagreement in computational analyses of mass spectrometry data of MHC-eluted peptides. Moreover, such mass spectrometric analyses cannot elucidate how much spliced peptides contribute to the pool of immunogenic antigens. In this Perspective, we explain the significance of knowing the contribution of spliced peptides for accurate analyses of peptidomes on one hand, and to serve as a potential source of targetable tumor antigens on the other hand. Toward a strategy for mass spectrometry independent estimation of the contribution of PCPS to the immunopeptidome, we first reviewed methodologies to identify MHC-presented spliced peptide antigens expressed by tumors. Data from these identifications allowed us to compile three independent datasets containing 103, 74, and 83 confirmed T cell antigens from cancer patients. Only 3.9%, 1.4%, and between 0% and 7.2% of these truly immunogenic antigens are produced by PCPS, therefore providing a marginal contribution to the pool of immunogenic tumor antigens. We conclude that spliced peptides will not serve as a comprehensive source to expand the number of targetable antigens for immunotherapies.


Assuntos
Antígenos de Neoplasias , Antígenos de Histocompatibilidade Classe I , Neoplasias , Complexo de Endopeptidases do Proteassoma , Processamento de Proteína , Linfócitos T , Apresentação de Antígeno , Antígenos de Neoplasias/metabolismo , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Neoplasias/imunologia , Peptídeos/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Linfócitos T/imunologia
8.
Cell Death Dis ; 13(7): 615, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35840557

RESUMO

Aggresome formation is a protective cellular response to counteract proteasome dysfunction by sequestering misfolded proteins and reducing proteotoxic stress. Autophagic degradation of the protein aggregates is considered to be a key compensating mechanism for balancing proteostasis. However, the precise role of autophagy in proteasome inhibition-induced aggresome biogenesis remains unclear. Herein, we demonstrate that in the early stage of proteasome inhibition, the maturation of the autophagosome is suppressed, which facilitates aggresome formation of misfolded proteins. Proteasome inhibition-induced phosphorylation of SQSTM1 T269/S272 inhibits its autophagic receptor activity and promotes aggresome formation of misfolded proteins. Inhibiting SQSTM1 T269/S272 phosphorylation using Doramapimod aggravates proteasome inhibitor-mediated cell damage and tumor suppression. Taken together, our data reveal a negative effect of autophagy on aggresome biogenesis and cell damage upon proteasome inhibition. Our study suggests a novel therapeutic intervention for proteasome inhibitor-mediated tumor treatment.


Assuntos
Complexo de Endopeptidases do Proteassoma , Proteínas Ubiquitinadas , Autofagia , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/farmacologia , Proteína Sequestossoma-1/genética , Proteína Sequestossoma-1/metabolismo , Proteínas Ubiquitinadas/metabolismo
9.
Curr Protoc ; 2(7): e490, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35849029

RESUMO

The proteasome is a multisubunit protein complex responsible for the degradation of proteins, making it essential in myriad cellular processes. Several reversible and irreversible peptide substrates inspired by known proteasome inhibitors have been developed to visualize it and monitor its activity; however, they have limited commercial availability or possess fluorophores that overlap with other known chemical probes, limiting their simultaneous use. The protocols presented here describe the synthesis of a clickable epoxomicin-based probe followed by the copper-catalyzed installment of an azide-containing fluorophore, and the application of the synthesized peptide in proteasome activity assays by SDS-PAGE and flow cytometry. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Solid-phase synthesis of clickable peptide fragment (2) Basic Protocol 2: In-solution coupling of epoxy-ketone moiety to fragment (2) Basic Protocol 3: Copper-catalyzed click reaction of (3) with fluorophore of choice Basic Protocol 4: Monitoring proteasome activity by SDS-PAGE in HEK-293T cells Alternate Protocol: Monitoring proteasome activity by flow cytometry in HEK-293T cells.


Assuntos
Cobre , Complexo de Endopeptidases do Proteassoma , Cobre/farmacologia , Corantes Fluorescentes , Oligopeptídeos , Peptídeos , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma
10.
Food Chem Toxicol ; 167: 113264, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35781037

RESUMO

Brain's metals accumulation is associated with toxic proteins, like amyloid-proteins (Aß), formation, accumulation, and aggregation, leading to neurodegeneration. Metals downregulate the correct folding, disaggregation, or degradation mechanisms of toxic proteins, as heat shock proteins (HSPs) and proteasome. The 7-amino-phenanthridin-6(5H)-one derivatives (APH) showed neuroprotective effects against metal-induced cell death through their antioxidant effect, independently of their chelating activity. However, additional neuroprotective mechanisms seem to be involved. We tested the most promising APH compounds (APH1-5, 10-100 µM) chemical ability to prevent metal-induced Aß proteins aggregation; the APH1-5 effect on HSP70 and proteasome 20S (P20S) expression, the metals effect on Aß formation and the involvement of HSP70 and P20S in the process, and the APH1-5 neuroprotective effects against Aß proteins (1 µM) and metals in SN56 cells. Our results show that APH1-5 compounds chemically avoid metal-induced Aß proteins aggregation and induce HSP70 and P20S expression. Additionally, iron and cadmium induced Aß proteins formation through downregulation of HSP70 and P20S. Finally, APH1-5 compounds protected against Aß proteins-induced neuronal cell death, reversing partially or completely this effect. These data may help to provide a new therapeutic approach against the neurotoxic effect induced by metals and other environmental pollutants, especially when mediated by toxic proteins.


Assuntos
Doença de Alzheimer , Fármacos Neuroprotetores , Peptídeos beta-Amiloides/metabolismo , Proteínas Amiloidogênicas , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismo , Humanos , Metais , Fármacos Neuroprotetores/farmacologia , Complexo de Endopeptidases do Proteassoma/metabolismo
11.
Biomolecules ; 12(7)2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35883481

RESUMO

Ubiquitin is a small protein that is conjugated to target proteins to signal a great number of critical biological processes. Impaired ubiquitin signaling and defects in the ubiquitin proteasome system (UPS) surveillance are implicated in many human diseases, including cancer. Characterization of the physiological roles of UPS components and their regulatory mechanisms is therefore vital for the identification of therapeutic targets and the development of tools and paradigms to better understand and treat human diseases. In this Special Issue, we assembled seven original research and review articles to provide insights on the multifaceted role of the UPS in pathogenesis and disease, covering the areas of molecular and cellular mechanisms of UPS enzymes, biochemical and biophysical characterization strategies, drug development, and targeted protein degradation.


Assuntos
Neoplasias , Ubiquitina , Humanos , Neoplasias/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Transdução de Sinais , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação
12.
Int J Mol Sci ; 23(15)2022 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-35897744

RESUMO

The dynamic balance of transcriptional and translational regulation together with degron-controlled proteolysis shapes the ever-changing cellular proteome. While a large variety of degradation signals has been characterized, our knowledge of cis-acting protein motifs that can in vivo stabilize otherwise short-lived proteins is very limited. We have identified and characterized a conserved 13-mer protein segment derived from the p54/Rpn10 ubiquitin receptor subunit of the Drosophila 26S proteasome, which fulfills all the characteristics of a protein stabilization motif (STABILON). Attachment of STABILON to various intracellular as well as medically relevant secreted model proteins resulted in a significant increase in their cellular or extracellular concentration in mammalian cells. We demonstrate that STABILON acts as a universal and dual function motif that, on the one hand, increases the concentration of the corresponding mRNAs and, on the other hand, prevents the degradation of short-lived fusion proteins. Therefore, STABILON may lead to a breakthrough in biomedical recombinant protein production.


Assuntos
Proteínas de Drosophila , Complexo de Endopeptidases do Proteassoma , Motivos de Aminoácidos , Animais , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Mamíferos/metabolismo , Complexo de Endopeptidases do Proteassoma/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise , Ubiquitina/metabolismo
13.
Cell Death Dis ; 13(7): 643, 2022 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-35871160

RESUMO

Doxorubicin (DOX)-based chemotherapy is widely used to treat malignant tumors; however, the cardiotoxicity induced by DOX restricts its clinical usage. A therapeutic dose of DOX can activate ubiquitin-proteasome system. However, whether and how ubiquitin-proteasome system brings out DOX-induced cardiotoxicity remains to be investigated. Here we conducted a proteomics analysis of a DOX-induced cardiotoxicity model to screen the potentially ubiquitination-related molecules. Dysregulated TRIM25 was found to contribute to the cardiotoxicity. In vivo and in vitro cardiotoxicity experiments revealed that TRIM25 ameliorated DOX-induced cardiotoxicity. Electron microscopy and endoplasmic reticulum stress markers revealed that TRIM25 mitigated endoplasmic reticulum stress and apoptosis in DOX-induced cardiomyocytes. Mechanistically, the Co-immunoprecipitation assays and CHX pulse-chase experiment determined that TRIM25 affected p85α stability and promoted its ubiquitination and degradation. This leads to increase of nuclear translocation of XBP-1s, which mitigates endoplasmic reticulum stress. These findings reveal that TRIM25 may have a therapeutic role for DOX-induced cardiotoxicity.


Assuntos
Cardiotoxicidade , Complexo de Endopeptidases do Proteassoma , Apoptose , Cardiotoxicidade/tratamento farmacológico , Cardiotoxicidade/etiologia , Cardiotoxicidade/metabolismo , Doxorrubicina/farmacologia , Humanos , Miócitos Cardíacos/metabolismo , Estresse Oxidativo , Complexo de Endopeptidases do Proteassoma/metabolismo , Ubiquitinas/metabolismo
14.
BMC Cancer ; 22(1): 735, 2022 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-35790913

RESUMO

BACKGROUND: The therapeutic armamentarium in multiple myeloma has been significantly broadened by proteasome inhibitors, highly efficient means in controlling of multiple myeloma. Despite the developments of therapeutic regimen in treatment of multiple myeloma, still the complete remission requires a novel therapeutic strategy with significant difference in outcomes. Proteasome inhibitors induce autophagy and ER stress, both pivotal pathways for protein homeostasis. Recent studies showed that the IRE1α-XBP1 axis of the unfolded protein response (UPR) is up-regulated in multiple myeloma patients. In addition, XBP1 is crucial for the maintenance of viability of acute lymphoblastic leukemia (ALL). RESULTS: We analyzed the efficacy of targeting IRE1α-XBP1 axis and autophagy in combination with proteasome inhibitor, ixazomib in treatment of multiple myeloma. In this present study, we first show that targeting the IRE1α-XBP1 axis with small molecule inhibitors (STF-083010, A106) together with the ixazomib induces cell cycle arrest with an additive cytotoxic effect in multiple myeloma. Further, we examined the efficacy of autophagy inhibitors (bafilomycin A, BAF and chloroquine, CQ) together with ixazomib in multiple myeloma and observed that this combination treatment synergistically reduced cell viability in multiple myeloma cell lines (viable cells Ixa: 51.8 ± 3.3, Ixa + BAF: 18.3 ± 7.2, Ixa + CQ: 38.4 ± 3.7) and patient-derived multiple myeloma cells (Ixa: 59.6 ± 4.4, Ixa + CQ: 7.0 ± 2.1). We observed, however, that this combined strategy leads to activation of stress-induced c-Jun N-terminal kinase (JNK). Cytotoxicity mediated by combined proteasome and autophagy inhibition was reversed by addition of the specific JNK inhibitor JNK-In-8 (viable cells: Ixa + BAF: 11.6 ± 7.0, Ixa + BAF + JNK-In-8: 30.9 ± 6.1). CONCLUSION: In this study we showed that combined inhibition of autophagy and the proteasome synergistically induces cell death in multiple myeloma. Hence, we consider the implication of pharmaceutical inhibition of autophagy together with proteasome inhibition and UPR-directed therapy as promising novel in vitro treatment strategy against multiple myeloma.


Assuntos
Mieloma Múltiplo , Inibidores de Proteassoma , Apoptose , Autofagia , Benzamidas , Linhagem Celular Tumoral , Endorribonucleases , Humanos , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/farmacologia , Inibidores de Proteassoma/uso terapêutico , Proteínas Serina-Treonina Quinases , Piridinas , Pirimidinas
15.
Front Cell Infect Microbiol ; 12: 925804, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35873166

RESUMO

Essential core pathways of cellular biology are preserved throughout evolution, highlighting the importance of these pathways for both bacteria and human cancer cells alike. Cell viability requires a proper balance between protein synthesis and degradation in order to maintain integrity of the proteome. Proteasomes are highly intricate, tightly regulated multisubunit complexes that are critical to achieve protein homeostasis (proteostasis) through the selective degradation of misfolded, redundant and damaged proteins. Proteasomes function as the catalytic core of the ubiquitin-proteasome pathway (UPP) which regulates a myriad of essential processes including growth, survival, differentiation, drug resistance and apoptosis. Proteasomes recognize and degrade proteins that have been marked by covalently attached poly-ubiquitin chains. Deregulation of the UPP has emerged as an essential etiology of many prominent diseases, including cancer. Proteasome inhibitors selectively target cancer cells, including those resistant to chemotherapy, while sparing healthy cells. Proteasome inhibition has emerged as a transformative anti-myeloma strategy that has extended survival for certain patient populations from 3 to 8 years. The structural architecture and functional activity of proteasomes is conserved from Archaea to humans to support the concept that proteasomes are actionable targets that can be inhibited in pathogenic organisms to improve the treatment of infectious diseases. Proteasomes have an essential role during all stages of the parasite life cycle and features that distinguish proteasomes in pathogens from human forms have been revealed. Advancement of inhibitors that target Plasmodium and Mycobacterial proteasomes is a means to improve treatment of malaria and tuberculosis. In addition, PIs may also synergize with current frontline agents support as resistance to conventional drugs continues to increase. The proteasome represents a highly promising, actionable target to combat infectious diseases that devastate lives and livelihoods around the globe.


Assuntos
Doenças Transmissíveis , Neoplasias , Archaea , Humanos , Neoplasias/tratamento farmacológico , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteínas , Ubiquitinas
16.
Cells ; 11(15)2022 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-35892577

RESUMO

REGγ, a proteasome activator belonging to the 11S (otherwise known as REG, PA28, or PSME) proteasome activator family, is widely present in many eukaryotes. By binding to the 20S catalytic core particle, REGγ acts as a molecular sieve to selectively target proteins for degradation in an ATP- and ubiquitin-independent manner. This non-canonical proteasome pathway directly regulates seemingly unrelated cellular processes including cell growth and proliferation, apoptosis, DNA damage response, immune response, and metabolism. By affecting different pathways, REGγ plays a vital role in the regulation of cellular life and death through the maintenance of protein homeostasis. As a promoter of cellular growth and a key regulator of several tumor suppressors, many recent studies have linked REGγ overexpression with tumor formation and suggested the REGγ-proteasome as a potential target of new cancer-drug development. This review will present an overview of the major functions of REGγ as it relates to the regulation of cellular life and death, along with new mechanistic insights into the regulation of REGγ.


Assuntos
Neoplasias , Complexo de Endopeptidases do Proteassoma , Autoantígenos/metabolismo , Ciclo Celular , Humanos , Neoplasias/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Ubiquitina/metabolismo
17.
Sci Rep ; 12(1): 12788, 2022 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-35896610

RESUMO

Proteasome inhibitors bortezomib and carfilzomib are the backbones of treatments of multiple myeloma, which remains incurable despite many recent advances. With many patients relapsing despite high initial response rates to proteasome inhibitor-containing regimens, it is critical to understand the process of acquired resistance. In vitro generated resistant cell lines are important tools in this process. The majority of previously developed bortezomib-resistant cell lines bear mutations in the proteasome PSMB5 sites, the prime target of bortezomib and carfilzomib, which are rarely observed in patients. Here we present a novel bortezomib-resistant derivative of the KMS-12-BM multiple myeloma cell line, KMS-12-BM-BPR. Unlike previously published bortezomib-resistant cell lines, it was created using clinically relevant twice-weekly pulse treatments with bortezomib instead of continuous incubation. It does not contain mutations in the PSMB5 site and retains its sensitivity to carfilzomib. Reduced load on proteasome due to decreased protein synthesis appears to be the main cause of resistance. In addition, KMS-12-BM-BPR cells are more sensitive to Bcl-2 inhibitor venetoclax. Overall, this study demonstrates the feasibility of creating a proteasome inhibitor resistant myeloma cell lines by using clinically relevant pulse treatments and provides a novel model of acquired resistance.


Assuntos
Antineoplásicos , Mieloma Múltiplo , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Bortezomib/farmacologia , Bortezomib/uso terapêutico , Compostos Bicíclicos Heterocíclicos com Pontes , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/genética , Humanos , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/genética , Mutação , Recidiva Local de Neoplasia , Complexo de Endopeptidases do Proteassoma/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/farmacologia , Sulfonamidas
18.
Int J Mol Sci ; 23(14)2022 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-35886949

RESUMO

The development and prevalence of diseases associated with aging presents a global health burden on society. One hallmark of aging is the loss of proteostasis which is caused in part by alterations to the ubiquitin-proteasome system (UPS) and lysosome-autophagy system leading to impaired function and maintenance of mass in tissues such as skeletal muscle. In the instance of skeletal muscle, the impairment of function occurs early in the aging process and is dependent on proteostatic mechanisms. The UPS plays a pivotal role in degradation of misfolded and aggregated proteins. For the purpose of this review, we will discuss the role of the UPS system in the context of age-related loss of muscle mass and function. We highlight the significant role that E3 ubiquitin ligases play in the turnover of key components (e.g., mitochondria and neuromuscular junction) essential to skeletal muscle function and the influence of aging. In addition, we will briefly discuss the contribution of the UPS system to lifespan. By understanding the UPS system as part of the proteostasis network in age-related diseases and disorders such as sarcopenia, new discoveries can be made and new interventions can be developed which will preserve muscle function and maintain quality of life with advancing age.


Assuntos
Longevidade , Ubiquitina , Músculo Esquelético/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Qualidade de Vida , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
19.
Nat Commun ; 13(1): 4146, 2022 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-35842429

RESUMO

Enhancing the removal of aggregate-prone toxic proteins is a rational therapeutic strategy for a number of neurodegenerative diseases, especially Huntington's disease and various spinocerebellar ataxias. Ideally, such approaches should preferentially clear the mutant/misfolded species, while having minimal impact on the stability of wild-type/normally-folded proteins. Furthermore, activation of both ubiquitin-proteasome and autophagy-lysosome routes may be advantageous, as this would allow effective clearance of both monomeric and oligomeric species, the latter which are inaccessible to the proteasome. Here we find that compounds that activate the D1 ATPase activity of VCP/p97 fulfill these requirements. Such effects are seen with small molecule VCP activators like SMER28, which activate autophagosome biogenesis by enhancing interactions of PI3K complex components to increase PI(3)P production, and also accelerate VCP-dependent proteasomal clearance of such substrates. Thus, this mode of VCP activation may be a very attractive target for many neurodegenerative diseases.


Assuntos
Adenosina Trifosfatases , Doenças Neurodegenerativas , Proteína com Valosina , Adenosina Trifosfatases/metabolismo , Autofagia , Proteínas de Ciclo Celular/metabolismo , Humanos , Doenças Neurodegenerativas/genética , Fosfatos de Fosfatidilinositol , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteína com Valosina/genética , Proteína com Valosina/metabolismo
20.
Artigo em Inglês | MEDLINE | ID: mdl-35750158

RESUMO

Atrogin-1 plays an important role in ubiquitin-proteasome proteolysis in vertebrate skeletal muscles. Recently, atrogin-1 has been shown to be involved in the autophagy-lysosome system, another proteolytic system, in the murine and fish hearts and skeletal muscles. With the aim to elucidate the effect of atrogin-1 on the autophagy-lysosome system in mammalian and avian skeletal muscles, this study has examined the effects of atrogin-1 knockdown on autophagy-lysosome-related proteins in C2C12 and chicken embryonic myotubes. Using the levels of microtubule-associated protein light chain 3 (LC3)-II protein, it was confirmed that atrogin-1 knockdown blocked the autophagic flux in both the myotubes. In addition, atrogin-1 knockdown in C2C12 myotubes significantly decreased the level of autophagy-related gene (ATG)12-ATG5 conjugate, which is supposedly necessary for the fusion of autophagosomes and lysosomes. Atrogin-1 knockdown also resulted in downregulation of forkhead box O3, a transcription factor for ATG12. These data suggest that atrogin-1 is essential for the normal autophagy-lysosome system in the striated muscles of vertebrates.


Assuntos
Lisossomos , Fibras Musculares Esqueléticas , Animais , Autofagia/genética , Lisossomos/metabolismo , Mamíferos/metabolismo , Camundongos , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas Associadas aos Microtúbulos/farmacologia , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Complexo de Endopeptidases do Proteassoma/farmacologia , Ubiquitina/metabolismo
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