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19S regulatory particle

Eunju Im, Jong Bok Yoon, Han-Woong Lee, Kwang Chul Chung
Human telomerase reverse transcriptase (hTERT) is the catalytic subunit of telomerase, an RNA-dependent DNA polymerase that elongates telomeric DNA. hTERT displays several extra-telomeric functions that are independent of its telomere-regulatory function, including tumor progression and neuronal cell death regulation. In this study, we evaluated these additional hTERT non-telomeric functions. We determined that hTERT interacts with several 19S and 20S proteasome subunits. The 19S regulatory particle and 20S core particle are part of 26S proteasome complex, which plays a central role in ubiquitin-dependent proteolysis...
September 20, 2016: Journal of Cellular Physiology
Adrien Rousseau, Anne Bertolotti
The proteasome is essential for the selective degradation of most cellular proteins, but how cells maintain adequate amounts of proteasome is unclear. Here we show that there is an evolutionarily conserved signalling pathway controlling proteasome homeostasis. Central to this pathway is TORC1, the inhibition of which induced all known yeast 19S regulatory particle assembly-chaperones (RACs), as well as proteasome subunits. Downstream of TORC1 inhibition, the yeast mitogen-activated protein kinase, Mpk1, acts to increase the supply of RACs and proteasome subunits under challenging conditions in order to maintain proteasomal degradation and cell viability...
August 11, 2016: Nature
Anna S Tsimokha, Julia J Zaykova, Andrew Bottrill, Nikolai A Barlev
Proteasome-mediated proteolysis is critical for regulation of vast majority of cellular processes. In addition to their well-documented functions in the nucleus and cytoplasm proteasomes have also been found in extracellular space. The origin and functions of these proteasomes, dubbed as circulating/plasmatic or extracellular proteasomes, are unclear. To gain insights into the molecular and functional differences between extracellular (EPs) and cellular proteasomes (CPs) we compared their subunit composition using iTRAQ-based quantitative proteomics (iTRAQ LC/MS-MS)...
July 19, 2016: Journal of Cellular Physiology
Yulia V Lyupina, Olga G Zatsepina, Marina V Serebryakova, Pavel A Erokhov, Svetlana B Abaturova, Oksana I Kravchuk, Olga V Orlova, Svetlana N Beljelarskaya, Andrey I Lavrov, Olga S Sokolova, Victor S Mikhailov
Baculoviruses are large DNA viruses that infect insect species such as Lepidoptera and are used in biotechnology for protein production and in agriculture as insecticides against crop pests. Baculoviruses require activity of host proteasomes for efficient reproduction, but how they control the cellular proteome and interact with the ubiquitin proteasome system (UPS) of infected cells remains unknown. In this report, we analyzed possible changes in the subunit composition of 26S proteasomes of the fall armyworm, Spodoptera frugiperda (Sf9), cells in the course of infection with the Autographa californica multiple nucleopolyhedrovirus (AcMNPV)...
June 2016: Biochimica et Biophysica Acta
Mahadevan Lakshminarasimhan, Gina Boanca, Charles A S Banks, Gaye L Hattem, Ana E Gabriel, Brad D Groppe, Christine Smoyer, Kate E Malanowski, Allison Peak, Laurence Florens, Michael P Washburn
The highly conserved yeast R2TP complex, consisting of Rvb1, Rvb2, Pih1, and Tah1, participates in diverse cellular processes ranging from assembly of protein complexes to apoptosis. Rvb1 and Rvb2 are closely related proteins belonging to the AAA+ superfamily and are essential for cell survival. Although Rvbs have been shown to be associated with various protein complexes including the Ino80 and Swr1chromatin remodeling complexes, we performed a systematic quantitative proteomic analysis of their associated proteins and identified two additional complexes that associate with Rvb1 and Rvb2: the chaperonin-containing T-complex and the 19S regulatory particle of the proteasome complex...
March 2016: Molecular & Cellular Proteomics: MCP
Paweł Śledź, Wolfgang Baumeister
The 26S proteasome is a 2.5-MDa complex, and it operates at the executive end of the ubiquitin-proteasome pathway. It is a proven target for therapeutic agents for the treatment of some cancers and autoimmune diseases, and moreover, it has potential as a target of antibacterial agents. Most inhibitors, including all molecules approved for clinical use, target the 20S proteolytic core complex; its structure was determined two decades ago. Hitherto, efforts to develop inhibitors targeting the 19S regulatory particle subunits have been less successful...
2016: Annual Review of Pharmacology and Toxicology
Sudarsanareddy Lokireddy, Nikolay Vadimovich Kukushkin, Alfred Lewis Goldberg
Although rates of protein degradation by the ubiquitin-proteasome pathway (UPS) are determined by their rates of ubiquitination, we show here that the proteasome's capacity to degrade ubiquitinated proteins is also tightly regulated. We studied the effects of cAMP-dependent protein kinase (PKA) on proteolysis by the UPS in several mammalian cell lines. Various agents that raise intracellular cAMP and activate PKA (activators of adenylate cyclase or inhibitors of phosphodiesterase 4) promoted degradation of short-lived (but not long-lived) cell proteins generally, model UPS substrates having different degrons, and aggregation-prone proteins associated with major neurodegenerative diseases, including mutant FUS (Fused in sarcoma), SOD1 (superoxide dismutase 1), TDP43 (TAR DNA-binding protein 43), and tau...
December 29, 2015: Proceedings of the National Academy of Sciences of the United States of America
Vladyslava Sokolova, Frances Li, George Polovin, Soyeon Park
In the proteasome, the proteolytic 20S core particle (CP) associates with the 19S regulatory particle (RP) to degrade polyubiquitinated proteins. Six ATPases (Rpt1-Rpt6) of the RP form a hexameric Rpt ring and interact with the heptameric α ring (α1-α7) of the CP via the Rpt C-terminal tails individually binding to the α subunits. Importantly, the Rpt6 tail has been suggested to be crucial for RP assembly. Here, we show that the interaction of the CP and Rpt6 tail promotes a CP-Rpt3 tail interaction, and that they jointly mediate proteasome activation via opening the CP gate for substrate entry...
2015: Scientific Reports
Madeline R Scott, Maria D Rubio, Vahram Haroutunian, James H Meador-Woodruff
The ubiquitin proteasome system (UPS) is a major regulator of protein processing, trafficking, and degradation. While protein ubiquitination is utilized for many cellular processes, one major function of this system is to target proteins to the proteasome for degradation. In schizophrenia, studies have found UPS transcript abnormalities in both blood and brain, and we have previously reported decreased protein expression of ubiquitin-associated proteins in brain. To test whether the proteasome is similarly dysregulated, we measured the protein expression of proteasome catalytic subunits as well as essential subunits from proteasome regulatory complexes in 14 pair-matched schizophrenia and comparison subjects in superior temporal cortex...
February 2016: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
Seok Keun Cho, Hansol Bae, Moon Young Ryu, Seong Wook Yang, Woo TaeK Kim
Drought stress strongly affects plant growth and development, directly connected with crop yields, accordingly. However, related to the function of U-BOX E3 ligases, the underlying molecular mechanisms of desiccation stress response in plants are still largely unknown. Here we report that PUB22 and PUB23, two U-box E3 ligase homologs, tether ubiquitins to 19S proteasome regulatory particle (RP) subunit RPN6, leading to its degradation. RPN6 was identified as an interacting substrate of PUB22 by yeast two-hybrid screening, and in vitro pull-down assay confirmed that RPN6 interacts not only with PUB22, but also with PUB23...
September 4, 2015: Biochemical and Biophysical Research Communications
Zanlin Yu, Nurit Livnat-Levanon, Oded Kleifeld, Wissam Mansour, Mark A Nakasone, Carlos A Castaneda, Emma K Dixon, David Fushman, Noa Reis, Elah Pick, Michael H Glickman
26S proteasome, a major regulatory protease in eukaryotes, consists of a 20S proteolytic core particle (CP) capped by a 19S regulatory particle (RP). The 19S RP is divisible into base and lid sub-complexes. Even within the lid, subunits have been demarcated into two modules: module 1 (Rpn5, Rpn6, Rpn8, Rpn9 and Rpn11), which interacts with both CP and base sub-complexes and module 2 (Rpn3, Rpn7, Rpn12 and Rpn15) that is attached mainly to module 1. We now show that suppression of RPN11 expression halted lid assembly yet enabled the base and 20S CP to pre-assemble and form a base-CP...
2015: Bioscience Reports
Pawel Leznicki, Jelena Korac-Prlic, Katarzyna Kliza, Koraljka Husnjak, Yvonne Nyathi, Ivan Dikic, Stephen High
Rpn13 is an intrinsic ubiquitin receptor of the 26S proteasome regulatory subunit that facilitates substrate capture prior to degradation. Here we show that the C-terminal region of Rpn13 binds to the tetratricopeptide repeat (TPR) domain of SGTA, a cytosolic factor implicated in the quality control of mislocalised membrane proteins (MLPs). The overexpression of SGTA results in a substantial increase in steady-state MLP levels, consistent with an effect on proteasomal degradation. However, this effect is strongly dependent upon the interaction of SGTA with the proteasomal component Rpn13...
September 1, 2015: Journal of Cell Science
Yanjie Li, Robert J Tomko, Mark Hochstrasser
In eukaryotes, damaged or unneeded proteins are typically degraded by the ubiquitin-proteasome system. In this system, the protein substrate is often first covalently modified with a chain of ubiquitin polypeptides. This chain serves as a signal for delivery to the 26S proteasome, a 2.5-MDa, ATP-dependent multisubunit protease complex. The proteasome consists of a barrel-shaped 20S core particle (CP) that is capped on one or both of its ends by a 19S regulatory particle (RP). The RP is responsible for recognizing the substrate, unfolding it, and translocating it into the CP for destruction...
2015: Current Protocols in Cell Biology
Cristinel Sandu, Nagaranjan Chandramouli, Joseph Fraser Glickman, Henrik Molina, Chueh-Ling Kuo, Nikolay Kukushkin, Alfred L Goldberg, Hermann Steller
Here, we report a novel mechanism of proteasome inhibition mediated by Thiostrepton (Thsp), which interacts covalently with Rpt subunits of the 19S proteasome and proteasome substrates. We identified Thsp in a cell-based high-throughput screen using a fluorescent reporter sensitive to degradation by the ubiquitin-proteasome pathway. Thiostrepton behaves as a proteasome inhibitor in several paradigms, including cell-based reporters, detection of global ubiquitination status, and proteasome-mediated labile protein degradation...
September 2015: Journal of Cellular and Molecular Medicine
Abhishek Sinha, Shankari Prasad Datta, Atrayee Ray, Srimonti Sarkar
BACKGROUND: Giardia lamblia switches its lifecycle between trophozoite and cyst forms and the proteasome plays a pivotal role in this switching event. Compared to most model eukaryotes, the proteasome of this parasite has already been documented to have certain variations. This study was undertaken to characterize the ubiquitin receptor, GlRpn10, of the 19S regulatory particle of the Giardia proteasome and determine its cellular localization in trophozoites, encysting trophozoites and cysts...
2015: Parasites & Vectors
Kasyapa Chitta, Aneel Paulus, Sharoon Akhtar, Maja Kristin K Blake, Thomas R Caulfield, Anne J Novak, Stephen M Ansell, Pooja Advani, Sikander Ailawadhi, Taimur Sher, Stig Linder, Asher Chanan-Khan
Deubiquitinase enzymes (DUBs) of the proteasomal 19S regulatory particle are emerging as important therapeutic targets in several malignancies. Here we demonstrate that inhibition of two proteasome-associated DUBs (USP14 and UCHL5) with the small molecule DUB inhibitor b-AP15, results in apoptosis of human Waldenström macroglobulinaemia (WM) cell lines and primary patient-derived WM tumour cells. Importantly, b-AP15 produced proteotoxic stress and apoptosis in WM cells that have acquired resistance to the proteasome inhibitor bortezomib...
May 2015: British Journal of Haematology
Marie-Luise Kaiser, Karin Römisch
Import of secretory proteins into the Endoplasmic Reticulum (ER) is an established function of the Sec61 channel. The contribution of the Sec61 channel to export of misfolded proteins from the ER for degradation by proteasomes is still controversial, but the proteasome 19S regulatory particle (RP) is necessary and sufficient for extraction of specific misfolded proteins from the ER, and binds directly to the Sec61 channel. In this work we have identified an import-competent sec61 mutant, S353C, carrying a point mutation in ER-lumenal loop 7 which reduces affinity of the cytoplasmic face of the Sec61 channel for the 19S RP...
2015: PloS One
Zanlin Yu, Nurit Livnat-Levanon, Oded Kleifeld, Wissam Mansour, Mark A Nakasone, Carlos A Castaneda, Emma K Dixon, David Fushman, Noa Reis, Elah Pick, Michael H Glickman
26S proteasome, a major regulatory protease in eukaryotes, consists of a 20S proteolytic core particle (CP) capped by a 19S regulatory particle (RP). The 19S RP is divisible into base and lid subcomplexes. Even within the lid, subunits have been demarcated into two modules: module 1 (Rpn5, Rpn6, Rpn8, Rpn9 and Rpn11), which interacts with both CP and base subcomplexes, and module 2 (Rpn3, Rpn7, Rpn12 and Rpn15) that is attached mainly to module 1. We now show that suppression of RPN11 expression halted lid assembly yet enabled the base and 20S CP to pre-assemble and form a base-CP...
January 27, 2015: Bioscience Reports
Iu Ia Zaĭkova, I N Evteeva, A S Tsimokha
The presented review concerns the intracellular proteasome and their possible functions. The ubiquitin-proteasome system (UPS) is responsible for the common regulated proteolysis in the cell. 26S proteasome is a central proteolytic unit of UPS and is a multisubunit protein complex consisting of a core catalytic complex, called 20S proteasome, capped at one or both ends by 19S regulatory complex. Proteasomes have been shown in the extracellular space: in alveolar and cerebrospinal fluids, blood plasma. Extracellular proteasomes are intact intracellular particles that exhibit three types of specific peptidase activity...
2013: Tsitologiia
Li Huang, Katherine Jung, Chin Ho Chen
The 26S proteasome is a cellular proteolytic complex containing 19S regulatory particles and the 20S core proteasome. It was reported that the small molecule b-AP15 targets the proteasome by inhibiting deubiquitination of the 19S regulatory particles of the proteasome complex. An investigation of b-AP15 on the 20S proteasome core suggested that this compound can also inhibit the 20S proteasome with a potency equivalent to that found to inhibit the 19S regulatory particles.
2014: Biomolecules
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