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20S proteasome

Maya A Olshina, Gili Ben-Nissan, Michal Sharon
No abstract text is available yet for this article.
December 12, 2017: Cell Cycle
Antonio Di Dato, Alessandra Cunsolo, Marco Persico, Anna Maria Santoro, Alessandro D'Urso, Danilo Milardi, Roberto Purrello, Manuela Stefanelli, Roberto Paolesse, Grazia R Tundo, Diego Sbardella, Caterina Fattorusso, Massimo Coletta
The importance of allosteric proteasome inhibition in the treatment of cancer is becoming increasingly evident. Motivated by this urgent therapeutic need, we have recently identified cationic porphyrins as a highly versatile class of molecules able to regulate proteasome activity by interfering with gating mechanisms. In the present study, the mapping of electrostatic contacts bridging the regulatory particles with the α-rings of the human 20S proteasome led us to the identification of (meso-tetrakis(4-N-methylphenyl pyridyl)-porphyrin (pTMPyPP4) as a novel non-competitive inhibitor of human 20S proteasome...
December 6, 2017: Scientific Reports
Gunter Schmidtke, Richard Schregle, Gerardo Alvarez, Eva M Huber, Marcus Groettrup
The 20S immunoproteasome (IP) is an interferon(IFN)-γ - and tumor necrosis factor (TNF) -inducible variant of the 20S constitutive proteasome (CP) in which all its peptidolytically active subunits β1, β2, and β5 are replaced by their cytokine inducible homologues β1i (LMP2), β2i (MECL-1), and β5i (LMP7). These subunit replacements alter the cleavage specificity of the proteasome and the spectrum of proteasome-generated peptide ligands of MHC class I molecules. In addition to antigen processing, the IP has recently been shown to serve unique functions in the generation of pro-inflammatory T helper cell subtypes and cytokines as well as in the pathogenesis of autoimmune diseases, but the mechanistic involvement of the IP in these processes has remained elusive...
December 2, 2017: Molecular Immunology
Justin Hartupee, Gabor D Szalai, Wei Wang, Xiucui Ma, Abhinav Diwan, Douglas L Mann
BACKGROUND: Sustained inflammation in the heart is sufficient to provoke left ventricular dysfunction and left ventricular remodeling. Although inflammation has been linked to many of the biological changes responsible for adverse left ventricular remodeling, the relationship between inflammation and protein quality control in the heart is not well understood. METHODS AND RESULTS: To study the relationship between chronic inflammation and protein quality control, we used a mouse model of dilated cardiomyopathy driven by cardiac restricted overexpression of TNF (tumor necrosis factor; Myh6-sTNF)...
December 2017: Circulation. Heart Failure
Tingting Chen, Jieqiong Tan, Zhengqing Wan, Yongyi Zou, Henok Kessete Afewerky, Zhuohua Zhang, Tongmei Zhang
Evidence continues to accumulate that pesticides are the leading candidates of environmental toxins that may contribute to the pathogenesis of Parkinson's disease. The mechanisms, however, remain largely unclear. According to epidemiological studies, we selected nine representative pesticides (paraquat, rotenone, chlorpyrifos, pendimethalin, endosulfan, fenpyroximate, tebufenpyrad, trichlorphon and carbaryl) which are commonly used in China and detected the effects of the pesticides on mitochondria and ubiquitin-proteasome system (UPS) function...
November 23, 2017: International Journal of Molecular Sciences
David G P van Ijzendoorn, Zary Forghany, Frauke Liebelt, Alfred C Vertegaal, Aart G Jochemsen, Judith V M G Bovée, Karoly Szuhai, David A Baker
Epithelioid hemangioma is a locally aggressive vascular neoplasm, found in bones and soft tissue, whose cause is currently unknown, but may involve oncogene activation. FOS was one of the earliest viral oncogenes to be characterized and normal cellular FOS forms part of the activator protein 1 (AP-1) transcription factor complex which plays a pivotal role in cell growth, differentiation and survival as well as the DNA damage response. Despite this, to date, a causal link between aberrant FOS function and naturally occurring tumors has not been established...
November 17, 2017: Journal of Biological Chemistry
Prahlad V Raninga, Giovanna Di Trapani, Kathryn F Tonissen
The DJ-1 protein was originally linked with Parkinson's disease and is now known to have antioxidant functions. The protein has three redox-sensitive cysteine residues, which are involved in its dimerisation and functional properties. A mildly oxidised form of DJ-1 is the most active form and protects cells from oxidative stress conditions. DJ-1 functions as an antioxidant through a variety of mechanisms, including a weak direct antioxidant activity by scavenging reactive oxygen species. DJ-1 also regulates a number of signalling pathways, including the inhibition of apoptosis signal-regulating kinase 1 (ASK1)-induced apoptosis under oxidative stress conditions...
2017: Advances in Experimental Medicine and Biology
Arjan Mofers, Paola Pellegrini, Stig Linder, Pádraig D'Arcy
Maintenance of protein homeostasis is a crucial process for the normal functioning of the cell. The regulated degradation of proteins is primarily facilitated by the ubiquitin proteasome system (UPS), a system of selective tagging of proteins with ubiquitin followed by proteasome-mediated proteolysis. The UPS is highly dynamic consisting of both ubiquitination and deubiquitination steps that modulate protein stabilization and degradation. Deregulation of protein stability is a common feature in the development and progression of numerous cancer types...
November 14, 2017: Cancer Metastasis Reviews
Toshiya Kozai, Taichiro Sekiguchi, Tadashi Satoh, Hirokazu Yagi, Koichi Kato, Takayuki Uchihashi
The 20S proteasome is a core particle of the eukaryotic proteasome responsible for proteolysis and is composed of layered α and β hetero-heptameric rings. The α7 subunit, which is one of components of the α ring, is known to self-assemble into a double-ringed homo-tetradecamer composed of two layers of the α7 heptameric ring. The α7 tetradecamer is known to disassemble upon the addition of α6 subunit, producing a 1:7 hetero-octameric α6-α7 complex. However, the detailed disassembly mechanism remains unclear...
November 13, 2017: Scientific Reports
Andrew Clerman, Zahid Noor, Rita Fishelevich, Virginia Lockatell, Brian S Hampton, Nirav G Shah, Mariah V Salcedo, Nevins W Todd, Sergei P Atamas, Irina G Luzina
Human mature interleukin-33 (MIL33) is a member of the IL-1 family and a potent regulator of immunity through its pro-T helper cell 2 (Th2) activity. Its precursor form, full-length interleukin-33 (FLIL33), is an intranuclear protein in many cell types, including fibroblasts, and its intracellular levels can change in response to stimuli. However, the mechanisms controlling the nuclear localization of FLIL33 or its stability in cells are not understood. Here, we identified importin-5 (IPO5), a member of the importin family of nuclear transport proteins, as an intracellular binding partner of FLIL33...
November 10, 2017: Journal of Biological Chemistry
Anna A Hovhannisyan, The Hien Pham, Dominique Bouvier, Xiao Tan, SiAmmar Touhar, Gevorg G Mkryan, Ashot M Dallakyan, Chahrazade El Amri, Gagik S Melikyan, Michèle Reboud-Ravaux, Michelle Bouvier-Durand
New series of thiophene-containing phenoxypropanolamines were synthesized and evaluated for their potency to inhibit the three proteolytic activities of the mammalian 20S proteasome. Noticeable inhibition of both ChT-L and PA activities was obtained with three compounds: one with unsubstituted phenoxypropanolamine group (7) and the two others with a p-Cl-substituted group (4 and 9). For three other compounds (3, 8 and 10), ChT-L activity alone was significantly inhibited. In silico docking performed on the β5 and β1 subunits bearing the respective ChT-L and PA catalytic sites showed features common to poses associated with active compounds...
October 23, 2017: Bioorganic & Medicinal Chemistry Letters
Maria Barandalla, Elisa Haucke, Bernd Fischer, Alexander Navarrete Santos, Silvia Colleoni, Cesare Galli, Anne Navarrete Santos, Giovanna Lazzari
The accumulation of advanced glycation end products (AGEs) occurs in ageing and in many degenerative diseases as a final outcome of persistent oxidative stress on cells and organs. Environmental alterations taking place during early embryonic development can also lead to oxidative damage, reactive oxygen species (ROS) production, and AGE accumulation. Whether similar mechanisms act on somatic and embryonic stem cells (ESC) exposed to oxidative stress is not known; and therefore, the modelling of oxidative stress in vitro on human ESC has been the focus of this study...
2017: Oxidative Medicine and Cellular Longevity
Jennifer C Peeler, Sophia Schedin-Weiss, Mariluz Soula, Manija A Kazmi, Thomas P Sakmar
How an optimal level of human dopamine D4 receptor (hD4R) is maintained in synaptic membranes is not known. We show here that hD4R is ubiquitinated in primary neurons. We go on to show that ubiquitin is attached to hD4R through isopeptide and ester bonds. When lysine (Lys) residues of the hD4R are substituted with arginine (Arg) residues, cellular D4R protein levels increase. A synergistic effect on D4R levels is noted when cytoplasmic serine (Ser) and threonine (Thr) residues are mutated. Chloroquine, an inhibitor of lysosomal degradation, did not have an effect on hD4R protein levels...
November 3, 2017: Journal of Biological Chemistry
Xin Chen, Jinjie Wu, Qianqian Yang, Xiaolan Zhang, Peiquan Zhang, Siyan Liao, Zhimin He, Xuejun Wang, Chong Zhao, Jinbao Liu
The ubiquitin-proteasome system (UPS) is indispensable to the protein quality control in eukaryotic cells. Due to the remarkable clinical success of using proteasome inhibitors for clinical treatment of multiple myeloma, it is anticipated that targeting the UPS upstream of the proteasome step be an effective strategy for cancer therapy. Deubiquitinases (DUB) are proteases that remove ubiquitin from target proteins and therefore regulate multiple cellular processes including some signaling pathways altered in cancer cells...
November 3, 2017: Biometals: An International Journal on the Role of Metal Ions in Biology, Biochemistry, and Medicine
Aditya Sunkaria, Aarti Yadav, Supriya Bhardwaj, Rajat Sandhir
Ubiquitin-proteasome system (UPS) has emerged as major molecular mechanism which modulates synaptic plasticity. However, very little is known about what happens if this system fails during postnatal brain development. In the present study, MG132 was administered intracerebroventricularly in BALB/c mice pups at postnatal day one (P1), a very crucial period for synaptogenesis. Both 20S proteasome and calpain activities were found to be reduced in the mid brain of MG132-administered pups after 24 h. Mice (P40) which received MG132 on P1 were subjected to Morris water maze (MWM) training...
October 26, 2017: Neuroscience
Marta Denel-Bobrowska, Małgorzata Łukawska, Barbara Bukowska, Arkadiusz Gajek, Irena Oszczapowicz, Agnieszka Marczak
BACKGROUND/AIM: Oxazolinodoxorubicin (O-DOX) and oxazolinodaunorubicin (O-DAU) are derivatives of anthracyclines (DOX and DAU) with a modified daunosamine moiety. We aimed to clarify their mechanisms of action by investigating intracellular accumulation and effects on the cell cycle, phosphatidylserine externalization, and proteasome 20S activity. MATERIALS AND METHODS: Experimental model consisted of SKOV-3, A549 and HepG2 cells. Compounds were used at the concentration of 80nM...
October 21, 2017: Toxicology in Vitro: An International Journal Published in Association with BIBRA
Maricela Viola-Rhenals, Kush Rohit Patel, Laura Jaimes-Santamaria, Guojun Wu, Jinbao Liu, Q Ping Dou
Disulfiram (DSF, also called tetraethylthiuram disulphide), a disulfide derivative of N,N-diethyldithiocarbamate (DEDTC), is an antialcoholism drug that is currently being repurposed as a promising anticancer drug. DSF has been investigated in many studies, including in vitro, in vivo, preclinical and clinical. Various mechanisms have been proposed to be responsible for the cytotoxic effect of DSF on cancer cells. DSF is a pro-drug which is converted to its metabolite DEDTC in human body. A complex of DEDTC with a metal ion [usually Cu(II) or Zn(II)] could be responsible for the anticancer activity of DSF in breast, prostate, glioblastoma, lung, melanoma, cervical, colorectal cancers as well as myeloma and leukemia...
October 23, 2017: Current Medicinal Chemistry
Arjen J Jakobi, Matthias Wilmanns, Carsten Sachse
Atomic models based on high-resolution density maps are the ultimate result of the cryo-EM structure determination process. Here, we introduce a general procedure for local sharpening of cryo-EM density maps based on prior knowledge of an atomic reference structure. The procedure optimizes contrast of cryo-EM densities by amplitude scaling against the radially averaged local falloff estimated from a windowed reference model. By testing the procedure using six cryo-EM structures of TRPV1, β-galactosidase, γ-secretase, ribosome-EF-Tu complex, 20S proteasome and RNA polymerase III, we illustrate how local sharpening can increase interpretability of density maps in particular in cases of resolution variation and facilitates model building and atomic model refinement...
October 23, 2017: ELife
Claire L Soave, Tracey Guerin, Jinbao Liu, Q Ping Dou
In the past 15 years, the proteasome has been validated as an anti-cancer drug target and 20S proteasome inhibitors (such as bortezomib and carfilzomib) have been approved by the FDA for the treatment of multiple myeloma and some other liquid tumors. However, there are shortcomings of clinical proteasome inhibitors, including severe toxicity, drug resistance, and no effect in solid tumors. At the same time, extensive research has been conducted in the areas of natural compounds and old drug repositioning towards the goal of discovering effective, economical, low toxicity proteasome-inhibitory anti-cancer drugs...
October 18, 2017: Cancer Metastasis Reviews
Patrick K Cullen, Nicole C Ferrara, Shane E Pullins, Fred J Helmstetter
Numerous studies have indicated that the consolidation of contextual fear memories supported by an aversive outcome like footshock requires de novo protein synthesis as well as protein degradation mediated by the ubiquitin-proteasome system (UPS). Context memory formed in the absence of an aversive stimulus by simple exposure to a novel environment requires de novo protein synthesis in both the dorsal (dHPC) and ventral (vHPC) hippocampus. However, the role of UPS-mediated protein degradation in the consolidation of context memory in the absence of a strong aversive stimulus has not been investigated...
November 2017: Learning & Memory
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