Epidithiodiketopiperazines inhibit protein degradation by targeting Proteasome Deubiquitinase Rpn11

The 26S proteasome is the major proteolytic machine for breaking down cytosolic and nuclear proteins in eukaryotes. Due to the lack of a suitable assay, it is difficult to measure routinely and quantitatively the breakdown of proteins by the 26S proteasome in vitro. In the present study, we developed an assay to monitor proteasome-mediated protein degradation. Using this assay, we discovered that epidithiodiketopiperazine (ETPs) blocked the degradation of our model substrate in vitro. Further characterization revealed that ETPs inhibited proteasome function by targeting the essential proteasomal deubiquitinase Rpn11 (POH1/PSMD14). ETPs also inhibited other JAMM (JAB1/MPN/Mov34 metalloenzyme) proteases such as Csn5 and AMSH. An improved ETP with fewer non-specific effects, SOP11, stabilized a subset of proteasome substrates in cells, induced the unfolded protein response, and led to cell death. SOP11 represents a class of Rpn11 inhibitor and provides an alternative route to develop proteasome inhibitors. [Abstract copyright: Copyright © 2018 Elsevier Ltd. All rights reserved.

Discovery of an Inhibitor of the Proteasome Subunit Rpn11

The proteasome plays a crucial role in degradation of normal proteins that happen to be constitutively or inducibly unstable, and in this capacity it plays a regulatory role. Additionally, it degrades abnormal/damaged/mutant/misfolded proteins, which serves a quality-control function. Inhibitors of the proteasome have been validated in the treatment of multiple myeloma, with several FDA-approved therapeutics. Rpn11 is a Zn^(2+)-dependent metalloisopeptidase that hydrolyzes ubiquitin from tagged proteins that are trafficked to the proteasome for degradation. A fragment-based drug discovery (FBDD) approach was utilized to identify fragments with activity against Rpn11. Screening of a library of metal-binding pharmacophores (MBPs) revealed that 8-thioquinoline (8TQ, IC_(50) value ∼2.5 μM) displayed strong inhibition of Rpn11. Further synthetic elaboration of 8TQ yielded a small molecule compound (35, IC_(50) value ∼400 nM) that is a potent and selective inhibitor of Rpn11 that blocks proliferation of tumor cells in culture

Capzimin is a potent and specific inhibitor of proteasome isopeptidase Rpn11

The proteasome is a vital cellular machine that maintains protein homeostasis, which is of particular importance in multiple myeloma and possibly other cancers. Targeting of proteasome 20S peptidase activity with bortezomib and carfilzomib has been widely used to treat myeloma. However, not all patients respond to these compounds, and those who do eventually suffer relapse. Therefore, there is an urgent and unmet need to develop new drugs that target proteostasis through different mechanisms. We identified quinoline-8-thiol (8TQ) as a first-in-class inhibitor of the proteasome 19S subunit Rpn11. A derivative of 8TQ, capzimin, shows >5-fold selectivity for Rpn11 over the related JAMM proteases and >2 logs selectivity over several other metalloenzymes. Capzimin stabilized proteasome substrates, induced an unfolded protein response, and blocked proliferation of cancer cells, including those resistant to bortezomib. Proteomic analysis revealed that capzimin stabilized a subset of polyubiquitinated substrates. Identification of capzimin offers an alternative path to develop proteasome inhibitors for cancer therapy

Innovative Methodology of On-Line Point Cloud Data Compression for Free-Form Surface Scanning Measurement

In order to obtain a highly accurate profile of a measured three-dimensional (3D) free-form surface, a scanning measuring device has to produce extremely dense point cloud data with a great sampling rate. Bottlenecks are created owing to inefficiencies in manipulating, storing and transferring these data, and parametric modelling from them is quite time-consuming work. In order to effectively compress the dense point cloud data obtained from a 3D free-form surface during the real-time scanning measuring process, this paper presents an innovative methodology of an on-line point cloud data compression algorithm for 3D free-form surface scanning measurement. It has the ability to identify and eliminate data redundancy caused by geometric feature similarity between adjacent scanning layers. At first, the new algorithm adopts the bi-Akima method to compress the initial point cloud data; next, the data redundancy existing in the compressed point cloud is further identified and eliminated; then, we can get the final compressed point cloud data. Finally, the experiment is conducted, and the results demonstrate that the proposed algorithm is capable of obtaining high-quality data compression results with higher data compression ratios than other existing on-line point cloud data compression/reduction methods

Consequences of gene flow between oilseed rape (<em>Brassica napus</em>) and its relatives

International audienceNumerous studies have focused on the probability of occurrence of gene flow between transgenic crops and their wild relatives and the likelihood of transgene escape, which should be assessed before the commercial release of transgenic crops. This review paper focuses on this issue for oilseed rape, Brassica napus L., a species that produces huge numbers of pollen grains and seeds. We analyze separately the distinct steps of gene flow: (1) pollen and seeds as vectors of gene flow; (2) spontaneous hybridization; (3) hybrid behavior, fitness cost due to hybridization and mechanisms of introgression; (4) and fitness benefit due to transgenes (e.g. herbicide resistance and Bt toxin). Some physical, biological and molecular means of transgene containment are also described. Although hybrids and first generation progeny are difficult to identify in fields and non-crop habitats, the literature shows that transgenes could readily introgress into Brassica rapa, Brassica juncea and Brassica oleracea, while introgression is expected to be rare with Brassica nigra, Hirschfeldia incana and Raphanus raphanistrum. The hybrids grow well but produce less seed than their wild parent. The difference declines with increasing generations. However, there is large uncertainty about the evolution of chromosome numbers and recombination, and many parameters of life history traits of hybrids and progeny are not determined with satisfactory confidence to build generic models capable to really cover the wide diversity of situations. We show that more studies are needed to strengthen and organize biological knowledge, which is a necessary prerequisite for model simulations to assess the practical and evolutionary outputs of introgression, and to provide guidelines for gene flow management

Promoting the Construction of Xiongan New Area Through Energy Revolution: General Idea and Implementation Route

Based on the strategic background, positioning, and objectives of the planning and construction of the Xiongan New Area, an analysis model framework is established for the requirements for energy revolution during the planning and construction of this area. We conclude that energy revolution can actively promote the construction of the Xiongan New Area. Specifically, energy technology revolution can aid the Xiongan New Area to become a global energy innovation center; the energy operation mode of this area can be reformed through energy system revolution; the planning and construction requirements of the Xiongan New Area can be satisfied through energy consumption revolution; and a safe and efficient energy supply system can be ensured through energy supply revolution. Furthermore, an urban energy supply system that is green, safe, efficient, smart-friendly, and future-leading can be created in the Xiongan New Area through the energy revolution, particularly through key projects regarding energy integrated operation systems, energy Internet, green and smart transportation systems, ultra-low-energy buildings, and energy saving and emission reduction

Effect of cold rolling process on microstructure and mechanical properties of high strength β titanium alloy thin sheets

The microstructure and mechanical properties of Ti-3.5Al-5Mo-6V-3Cr-2Sn-0.5Fe high strength titanium alloy sheets prepared by unidirectional cold rolling and two-step cross cold rolling were investigated. Results showed that the β phase grains were refined significantly by cold rolling followed by solution treatment for a short time. Compared to unidirectional cold rolling, the short time solution treatment after two-step cross rolling could significantly reduce the non-uniformity of the microstructure of the alloy sheets. After aging treatment at 550 °C, the anisotropy of the mechanical properties still existed in the unidirectional rolled sheets, and the tensile strength was highest along the rolling direction. After solution and aging treatment, the anisotropy of the mechanical properties of the two-step cross rolling process sheet was not obvious than unidirectional cold rolling, and alloy had good strength and plasticity matching. Keywords: Cold rolling process, High strength β titanium alloy, Microstructure, Mechanical propertie

The Influences of Process Annealing Temperature on Microstructure and Mechanical Properties of near β High Strength Titanium Alloy Sheet

The influences of process annealing temperature during cold rolling on microstructure and mechanical properties of Ti-3.5Al-5Mo-6V-3Cr-2Sn-0.5Fe near &#946; high strength titanium alloy sheets have been investigated. Results showed that the alloy mainly included the deformation induced dislocation structures after cold rolling but no obvious band structure, twin crystal or martensite were observed in this work. The texture components, which were affected by process annealing, are mainly &#947;-fiber, &#945;-fiber and weak Goss texture. The &#947;-fiber of alloy when process annealed at 780 &#176;C (&#945;/&#946; phase field) is stronger than at 830 &#176;C (&#946; phase field), where the Goss texture of alloy with process annealing temperature of 830 &#176;C is more obvious. Results of annealing heat treatments showed that the recrystallization of the cold rolled was basically completed in a relatively short time of 2 min at 750 &#176;C for 2 min. The refinement of grain size led to a significant increase of plasticity compared to rolled alloy. Results of tensile testing of aged alloy display the excellent combination of strength and plasticity, and the cold rolled alloy with process annealed at &#945;/&#946; phase field exhibits the better mechanical properties than at &#946; phase field