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20S proteasome

Zhanyu Ding, Zhenglin Fu, Cong Xu, Yifan Wang, Yanxing Wang, Junrui Li, Liangliang Kong, Jinhuan Chen, Na Li, Rongguang Zhang, Yao Cong
The 26S proteasome is an ATP-dependent dynamic 2.5 MDa protease that regulates numerous essential cellular functions through degradation of ubiquitinated substrates. Here we present a near-atomic-resolution cryo-EM map of the S. cerevisiae 26S proteasome in complex with ADP-AlFx. Our biochemical and structural data reveal that the proteasome-ADP-AlFx is in an activated state, displaying a distinct conformational configuration especially in the AAA-ATPase motor region. Noteworthy, this map demonstrates an asymmetric nucleotide binding pattern with four consecutive AAA-ATPase subunits bound with nucleotide...
January 20, 2017: Cell Research
K Lockhart Jamieson, Victor Samokhvalov, Maria Akhnokh, Kyra Lee, Woo Jung Cho, Abhijit Takawale, Xiuhua Wang, Zamaneh Kassiri, John M Seubert
BACKGROUND: Pathophysiological responses, including cardiovascular complications, often alter with age. Cardioprotective effects of epoxyeicosatrienoic acids (EETs) toward acute myocardial ischemia-reperfusion injury have been well documented. However, biological relevance of EET-evoked cardioprotection in the ageing myocardium remains unknown. EETs are metabolized to less active metabolites by the enzyme soluble epoxide hydrolase (sEH). This study uses permanent occlusion of the left anterior descending artery (LAD) in young and aged sEH null and WT mice to compare cardiac and mitochondrial function following ischemic injury...
January 16, 2017: Prostaglandins & Other Lipid Mediators
Darci J Trader, Scott Simanski, Paige Dickson, Thomas Kodadek
BACKGROUND: The proteasome catalyzes the degradation of many mis-folded proteins, which are otherwise cytotoxic. There is interest in the discovery of proteasome agonists, but previous efforts to do so have been disappointing. METHODS: The cleavage of small fluorogenic peptides is used routinely as an assay to screen for proteasome modulators. We have developed follow-on assays that employ more physiologically relevant substrates. RESULTS: To demonstrate the efficacy of this workflow, the NIH Clinical Collection (NCC) was screened...
January 5, 2017: Biochimica et Biophysica Acta
Dilrajkaur Panfair, Andrew R Kusmierczyk
Proteasomes are found in all domains of life. They provide the major route of intracellular protein degradation in eukaryotes, though their assembly is not completely understood. All proteasomes contain a structurally conserved core particle (CP), or 20S proteasome, containing two heptameric β subunit rings sandwiched between two heptameric α subunit rings. Archaeal 20S proteasomes are compositionally simpler compared to their eukaryotic counterparts, yet they both share a common assembly mechanism. Consequently, archaeal 20S proteasomes continue to be important models for eukaryotic proteasome assembly...
December 17, 2016: Journal of Visualized Experiments: JoVE
Longze Sha, Xueqin Wang, Jing Li, Xinze Shi, Liwen Wu, Yan Shen, Qi Xu
The glutamate transporter GLT-1 is critical for the maintenance of low interstitial glutamate concentrations. Loss of GLT-1 is commonly observed in neurological disorders, including temporal lobe epilepsy (TLE). Despite the hypothesis that targeting the mechanisms of GLT-1 deficiency may be a novel strategy for treating drug-resistant epilepsy, the underlying molecular cascade remains largely unknown. Here, we show that Hsp90β is up-regulated in reactive astrocytes of the epileptic hippocampus in patients with TLE and mouse models of epilepsy...
December 27, 2016: Journal of Experimental Medicine
Rangxiao Zhuang, Lixin Gao, Xiaoqing Lv, Jianjun Xi, Li Sheng, Yanmei Zhao, Ruoyu He, Xiaobei Hu, Yidan Shao, Xuwang Pan, Shourong Liu, Weiwei Huang, Yubo Zhou, Jia Li, Jiankang Zhang
A series of novel piperazine or piperidine-containing non-covalent peptidyl derivatives possessing a neopentyl-asparagine residue were designed, synthesized and evaluated as proteasome inhibitors. All target compounds were screened for their 20S proteasome chymotrypsin-like inhibitory activities, and 15 ones displayed more potent activities than carfilzomib with IC50 values lower than 10 nM. Subsequently, the most potent 10 analogues were tested for their cytotoxic activities against two multiple myeloma (MM) cell lines RPMI-8226 and MM-1S...
December 18, 2016: European Journal of Medicinal Chemistry
Ayesha Ismail, Bindu Noolu, Ramesh Gogulothu, Shyam Perugu, Ajumeera Rajanna, Suresh K Babu
Murraya koenigii (curry tree) leaves are rich in bioactive compounds such as flavonoids, alkaloids, and coumarins. Alkaloids from M. koenigii leaves have antianalgesic, antiulcerogenic, antiobesity, and antitumor activities. In this study, we tested the cytotoxic and proteasome-inhibitory potential of a total alkaloid extract (TAE) from M. koenigii leaves in the breast cancer cell line MDA-MB-231. The TAE decreased cell viability with an IC50 of 14.4 μg/mL and altered growth kinetics of breast cancer cells...
December 2016: Journal of Medicinal Food
Hao-Chi Hsu, Pradeep K Singh, Hao Fan, Rong Wang, George Sukenick, Carl Nathan, Gang Lin, Huilin Li
The Mycobacterium tuberculosis (Mtb) 20S proteasome is vital for the pathogen to survive under nitrosative stress in vitro and to persist in mice. To qualify for drug development, inhibitors targeting Mtb 20S must spare both the human constitutive proteasome (c-20S) and immunoproteasome (i-20S). We recently reported members of a family of noncovalently binding dipeptide proteasome inhibitors that are highly potent and selective for Mtb 20S over human c-20S and i-20S. To understand the structural basis of their potency and selectivity, we have studied the structure-activity relationship of six derivatives and solved their cocrystal structures with Mtb 20S...
December 27, 2016: Biochemistry
Sai Chaitanya Chiliveri, Mandar V Deshmukh
The advent of Transverse Relaxation Optimized SpectroscopY (TROSY) and perdeuteration allowed biomolecular NMR spectroscopists to overcome the size limitation barrier (approx. 20 kDa) in de novo structure determination of proteins. The utility of these techniques was immediately demonstrated on large proteins and protein complexes (e.g. GroELGroES, ClpP protease, Hsp90-p53, 20S proteasome, etc.). Further, recent methodological developments such as Residual Dipolar Couplings and Paramagnetic Relaxation Enhancement allowed accurate measurement of long-range structural restraints...
December 2016: Journal of Biosciences
Esilida Sula Karreci, Hao Fan, Mayuko Uehara, Albana B Mihali, Pradeep K Singh, Ahmed T Kurdi, Zhabiz Solhjou, Leonardo V Riella, Irene Ghobrial, Teresina Laragione, Sujit Routray, Jean Pierre Assaker, Rong Wang, George Sukenick, Lei Shi, Franck J Barrat, Carl F Nathan, Gang Lin, Jamil Azzi
Constitutive proteasomes (c-20S) are ubiquitously expressed cellular proteases that degrade polyubiquitinated proteins and regulate cell functions. An isoform of proteasome, the immunoproteasome (i-20S), is highly expressed in human T cells, dendritic cells (DCs), and B cells, suggesting that it could be a potential target for inflammatory diseases, including those involving autoimmunity and alloimmunity. Here, we describe DPLG3, a rationally designed, noncovalent inhibitor of the immunoproteasome chymotryptic subunit β5i that has thousands-fold selectivity over constitutive β5c...
December 27, 2016: Proceedings of the National Academy of Sciences of the United States of America
Maria L V Reiss-Pistilli, Detlef Schuppan, Madalena M S Barroso, Iranaia Assunção-Miranda, Shirley Farias, Letícia Lery, Michael Bauer, Luiz Juliano, Maria A Juliano, Tatiana Coelho-Sampaio
Endostatin is a potent anti-angiogenic and anti-tumor protein capable of regressing tumors without inducing acquired resistance. Since it is a fragment of the parental molecule, collagen XVIII, its endogenous production depends on the activity of a specific proteolytic enzyme. While such an enzyme has been described in mice, a human counterpart has not been identified so far. Here, we searched for this enzyme by using a fluorescence resonance energy transfer peptide containing the cleavage site of human collagen XVIII...
December 5, 2016: Angiogenesis
Richard Arkwright, Tri Minh Pham, Jeffrey A Zonder, Q Ping Dou
Mantle cell lymphoma (MCL) is an incurable, often aggressive B-cell malignancy. Bortezomib (BTZ), the 20S proteasome inhibitor was originally developed and approved for treatment of relapsed refractory multiple myeloma, and subsequently approved for treatment of MCL. BTZ's single-agent activity induces clinical responses in approximately one-third of relapsed MCL patients. BTZ-containing combination therapies have further improved the quality and duration of clinical responses compared to standard chemotherapies in previously untreated MCL patients...
December 20, 2016: Expert Opinion on Drug Discovery
Yanyu Zhang, Hongyan Lu, Huimin Ju, Ming Chang, Qiuxia Wang, Qiang Zhang
Objective To establish a hyperoxia-exposed cell damage model of primary cultured premature rat alveolar type II epithelial cells (AECIIs) and investigate the effect of hyperoxia on ubiquitinated protein degradation and apoptosis of AECIIs. Methods Primary cultured premature rat AECIIs in vitro were divided into air group and hyperoxia group, which were exposed to air and 950 mL/L O2, respectively. After 24-, 48- and 72-hour exposure, isothiocyanate-labeled annexinV/propidium iodide (annexinV-FITC/PI) double staining combined with flow cytometry was utilized to detect the apoptosis of AECIIs...
December 2016: Xi Bao Yu Fen Zi Mian Yi Xue za Zhi, Chinese Journal of Cellular and Molecular Immunology
Jian-Mei Qin, Ri-Zhen Huang, Gui-Yang Yao, Zhi-Xin Liao, Ying-Ming Pan, Heng-Shan Wang
A series of inhibitors of 20S proteasome based on terminal functionalized dipeptide derivatives containing the thiourea moiety were synthesized and evaluated for inhibition of 20S proteasome and the effects of multidrug-resistance reversers. These compounds exhibited significant selectivity to the β5-subunit of the human 20S proteasome with IC50 values at submicromolar concentrations. A docking study of the most active compound 6i revealed key interactions between 6i and the active site of the 20S proteasome in which the thiourea moiety and a nitro group were important for improving activity...
November 11, 2016: European Journal of Medicinal Chemistry
Xiaoying Lan, Chong Zhao, Xin Chen, Peiquan Zhang, Dan Zang, Jinjie Wu, Jinghong Chen, Huidan Long, Li Yang, Hongbiao Huang, Bing Z Carter, Xuejun Wang, Xianping Shi, Jinbao Liu
BACKGROUND: Acquired imatinib (IM) resistance is frequently characterized by Bcr-Abl mutations that affect IM binding and kinase inhibition in patients with chronic myelogenous leukemia (CML). Bcr-Abl-T315I mutation is the predominant mechanism of the acquired resistance to IM. Therefore, it is urgent to search for additional approaches and targeting strategies to overcome IM resistance. We recently reported that nickel pyrithione (NiPT) potently inhibits the ubiquitin proteasome system via targeting the 19S proteasome-associated deubiquitinases (UCHL5 and USP14), without effecting on the 20S proteasome...
November 25, 2016: Journal of Hematology & Oncology
Daniela Correia da Silva, Paula B Andrade, Vera Ribeiro, Patrícia Valentão, David Pereira
BACKGROUND: The proteasome is the major proteolytic site on the eukaryotic cell, degrading most of its short-lived or misfolded polypeptides. The ubiquitin-proteasome pathway has been found to play a fundamental role in the development of several pathologies, from cancer to neurodegenerative diseases, or even retroviral infections. Nature remains a powerful source for the discovery of bioactive compounds. Recently, a number of molecules of natural origin, as well as natural product derivatives, have been described as proteasome inhibitors...
November 23, 2016: Recent Patents on Anti-cancer Drug Discovery
Anne E Todgham, Timothy A Crombie, Gretchen E Hofmann
There is an accumulating body of evidence suggesting that the sub-zero Antarctic marine environment places physiological constraints on protein homeostasis. Levels of ubiquitin (Ub)-conjugated proteins, 20S proteasome activity and mRNA expression of many proteins involved in both the ubiquitin (Ub) tagging of damaged proteins as well as the different complexes of the 26S proteasome were measured to examine whether there is thermal compensation of the Ub-proteasome pathway in Antarctic fishes to better understand the efficiency of the protein degradation machinery in polar species...
November 21, 2016: Journal of Experimental Biology
Alberto Valdés, Virginia García-Cañas, Konstantin A Artemenko, Carolina Simó, Jonas Bergquist, Alejandro Cifuentes
Carnosic acid (CA) and carnosol (CS) are two structurally related diterpenes present in rosemary herb (Rosmarinus officinalis). Although several studies have demonstrated that both diterpenes can scavenge free radicals and interfere in cellular processes such as cell proliferation, they may not necessarily exert the same effects at the molecular level. In this work, a shotgun proteomics study based on stable isotope dimethyl labeling (DML) and nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) has been performed to identify the relative changes in proteins and to gain some light on the specific molecular targets and mechanisms of action of CA and CS in HT-29 colon cancer cells...
January 2017: Molecular & Cellular Proteomics: MCP
Tao Wu, Mei-Xia Ren, Guo-Ping Chen, Zheng-Ming Jin, Gang Wang
Riken 2810430M08 (hereinafter referred to as Rrp15) is a newly identified and reported gene from the mouse genome. In our previous work, we found that the gene had a relationship with the proliferation and activation of T cells. Rrp15 protein is highly homologous with RRP15 (budding yeast), which has an important role in ribosomal RNA processing. We explored the potential function of Rrp15 in apoptosis, cell proliferation, and its involvement with RNA in the nucleus. We constructed a knockdown of the Rrp15 gene in NIH3T3 cells and then performed real-time PCR, western blotting, flow cytometry, and immunofluorescence to determine the function of the Rrp15 gene...
November 2016: FEBS Open Bio
In Soo Oh, Kathrin Textoris-Taube, Pil Soo Sung, Wonseok Kang, Xenia Gorny, Thilo Kähne, Seon-Hui Hong, Young Joon Choi, Clemens Cammann, Michael Naumann, Jong Hoon Kim, Su-Hyung Park, Ook Joon Yoo, Peter M Kloetzel, Ulrike Seifert, Eui-Cheol Shin
By changing the relative abundance of generated antigenic peptides through alterations in the proteolytic activity, interferon (IFN)-γ-induced immunoproteasomes influence the outcome of CD8(+) cytotoxic T lymphocyte responses. In the present study, we investigated the effects of hepatitis C virus (HCV) infection on IFN-γ-induced immunoproteasome expression using a HCV infection cell culture system. We found that, although IFN-γ induced the transcriptional expression of mRNAs encoding the β1i/LMP2, β2i/MECL-1 and β5i/LMP7 immunoproteasome subunits, the formation of immunoproteasomes was significantly suppressed in HCV-infected cells...
November 11, 2016: Experimental & Molecular Medicine
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