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Lagunes L, Briggs K, Martin-Holder P, Xu Z, Maurer D, Ghabra K, Deeds EJ. Modeling reveals the strength of weak interactions in stacked-ring assembly. Biophys J 2024:S0006-3495(24)00329-1. [PMID: 38762753 DOI: 10.1016/j.bpj.2024.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/30/2024] [Accepted: 05/15/2024] [Indexed: 05/20/2024] Open
Abstract
Cells employ many large macromolecular machines for the execution and regulation of processes that are vital for cell and organismal viability. Interestingly, cells cannot synthesize these machines as functioning units. Instead, cells synthesize the molecular parts that must then assemble into the functional complex. Many important machines, including chaperones such as GroEL and proteases such as the proteasome, comprise protein rings that are stacked on top of one another. While there is some experimental data regarding how stacked-ring complexes such as the proteasome self-assemble, a comprehensive understanding of the dynamics of stacked-ring assembly is currently lacking. Here, we developed a mathematical model of stacked-trimer assembly and performed an analysis of the assembly of the stacked homomeric trimer, which is the simplest stacked-ring architecture. We found that stacked rings are particularly susceptible to a form of kinetic trapping that we term "deadlock," in which the system gets stuck in a state where there are many large intermediates that are not the fully assembled structure but that cannot productively react. When interaction affinities are uniformly strong, deadlock severely limits assembly yield. We thus predicted that stacked rings would avoid situations where all interfaces in the structure have high affinity. Analysis of available crystal structures indicated that indeed the majority-if not all-of stacked trimers do not contain uniformly strong interactions. Finally, to better understand the origins of deadlock, we developed a formal pathway analysis and showed that, when all the binding affinities are strong, many of the possible pathways are utilized. In contrast, optimal assembly strategies utilize only a small number of pathways. Our work suggests that deadlock is a critical factor influencing the evolution of macromolecular machines and provides general principles for understanding the self-assembly efficiency of existing machines.
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Affiliation(s)
- Leonila Lagunes
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, California; Institute for Quantitative and Computational Biosciences, UCLA, Los Angeles, California
| | - Koan Briggs
- Department of Physics, University of Kansas, Lawrence, Kansas
| | - Paige Martin-Holder
- Department of Molecular Immunology, Microbiology and Genetics, UCLA, Los Angeles, California
| | - Zaikun Xu
- Center for Computational Biology, University of Kansas, Lawrence, Kansas
| | - Dustin Maurer
- Center for Computational Biology, University of Kansas, Lawrence, Kansas
| | - Karim Ghabra
- Computational and Systems Biology IDP, UCLA, Los Angeles, California
| | - Eric J Deeds
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, California; Institute for Quantitative and Computational Biosciences, UCLA, Los Angeles, California; Center for Computational Biology, University of Kansas, Lawrence, Kansas.
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2
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Yan S, Wang Y, Yu B, Gan Y, Lei J, Chen C, Zhu Z, Qiu Z, Cao B. A putative E3 ubiquitin ligase substrate receptor degrades transcription factor SmNAC to enhance bacterial wilt resistance in eggplant. HORTICULTURE RESEARCH 2024; 11:uhad246. [PMID: 38239808 PMCID: PMC10794948 DOI: 10.1093/hr/uhad246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 11/12/2023] [Indexed: 01/22/2024]
Abstract
Bacterial wilt caused by Ralstonia solanacearum is a severe soil-borne disease globally, limiting the production in Solanaceae plants. SmNAC negatively regulated eggplant resistance to Bacterial wilt (BW) though restraining salicylic acid (SA) biosynthesis. However, other mechanisms through which SmNAC regulates BW resistance remain unknown. Here, we identified an interaction factor, SmDDA1b, encoding a substrate receptor for E3 ubiquitin ligase, from the eggplant cDNA library using SmNAC as bait. SmDDA1b expression was promoted by R. solanacearum inoculation and exogenous SA treatment. The virus-induced gene silencing of the SmDDA1b suppressed the BW resistance of eggplants; SmDDA1b overexpression enhanced the BW resistance of tomato plants. SmDDA1b positively regulates BW resistance by inhibiting the spread of R. solanacearum within plants. The SA content and the SA biosynthesis gene ICS1 and signaling pathway genes decreased in the SmDDA1b-silenced plants but increased in SmDDA1b-overexpression plants. Moreover, SmDDB1 protein showed interaction with SmCUL4 and SmDDA1b and protein degradation experiments indicated that SmDDA1b reduced SmNAC protein levels through proteasome degradation. Furthermore, SmNAC could directly bind the SmDDA1b promoter and repress its transcription. Thus, SmDDA1b is a novel regulator functioning in BW resistance of solanaceous crops via the SmNAC-mediated SA pathway. Those results also revealed a negative feedback loop between SmDDA1b and SmNAC controlling BW resistance.
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Affiliation(s)
- Shuangshuang Yan
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture and Rural Affairs/Guangdong Vegetable Engineering and Technology Research Center, Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Yixi Wang
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture and Rural Affairs/Guangdong Vegetable Engineering and Technology Research Center, Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Bingwei Yu
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture and Rural Affairs/Guangdong Vegetable Engineering and Technology Research Center, Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Yuwei Gan
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture and Rural Affairs/Guangdong Vegetable Engineering and Technology Research Center, Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Jianjun Lei
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture and Rural Affairs/Guangdong Vegetable Engineering and Technology Research Center, Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Changming Chen
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture and Rural Affairs/Guangdong Vegetable Engineering and Technology Research Center, Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Zhangsheng Zhu
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture and Rural Affairs/Guangdong Vegetable Engineering and Technology Research Center, Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Zhengkun Qiu
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture and Rural Affairs/Guangdong Vegetable Engineering and Technology Research Center, Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Bihao Cao
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture and Rural Affairs/Guangdong Vegetable Engineering and Technology Research Center, Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou 510642, China
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3
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Rashid MU, Lorzadeh S, Gao A, Ghavami S, Coombs KM. PSMA2 knockdown impacts expression of proteins involved in immune and cellular stress responses in human lung cells. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166617. [PMID: 36481484 DOI: 10.1016/j.bbadis.2022.166617] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 11/21/2022] [Accepted: 11/28/2022] [Indexed: 12/12/2022]
Abstract
Proteasome subunit alpha type-2 (PSMA2) is a critical component of the 20S proteasome, which is the core particle of the 26S proteasome complex and is involved in cellular protein quality control by recognizing and recycling defective proteins. PSMA2 expression dysregulation has been detected in different human diseases and viral infections. No study yet has reported PSMA2 knockdown (KD) effects on the cellular proteome. METHODS We used SOMAScan, an aptamer-based multiplexed technique, to measure >1300 human proteins to determine the impact of PSMA2 KD on A549 human lung epithelial cells. RESULTS PSMA2 KD resulted in significant dysregulation of 52 cellular proteins involved in different bio-functions, including cellular movement and development, cell death and survival, and cancer. The immune system and signal transduction were the most affected cellular functions. PSMA2 KD caused dysregulation of several signaling pathways involved in immune response, cytokine signaling, organismal growth and development, cellular stress and injury (including autophagy and unfolded protein response), and cancer responses. CONCLUSIONS In summary, this study helps us better understand the importance of PSMA2 in different cellular functions, signaling pathways, and human diseases.
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Affiliation(s)
- Mahamud-Ur Rashid
- University of Manitoba, Department of Medical Microbiology & Infectious Diseases, Room 543 Basic Medical Sciences Building, 745 Bannatyne Ave., Winnipeg, MB R3E 0J9, Canada; Manitoba Centre for Proteomics & Systems Biology, Room 799, 715 McDermot Ave., Winnipeg, MB R3E 3P4, Canada
| | - Shahrokh Lorzadeh
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3E 0V9, Canada
| | - Ang Gao
- Manitoba Centre for Proteomics & Systems Biology, Room 799, 715 McDermot Ave., Winnipeg, MB R3E 3P4, Canada
| | - Saeid Ghavami
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3E 0V9, Canada; Research Institutes of Oncology and Hematology, Cancer Care Manitoba-University of Manitoba, Winnipeg, MB R3E 0V9, Canada; Biology of Breathing Theme, Children Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB R3E 0V9, Canada
| | - Kevin M Coombs
- University of Manitoba, Department of Medical Microbiology & Infectious Diseases, Room 543 Basic Medical Sciences Building, 745 Bannatyne Ave., Winnipeg, MB R3E 0J9, Canada; Manitoba Centre for Proteomics & Systems Biology, Room 799, 715 McDermot Ave., Winnipeg, MB R3E 3P4, Canada; Children's Hospital Research Institute of Manitoba, Room 513, 715 McDermot Ave., Winnipeg, MB R3E 3P4, Canada.
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4
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Structure of the reduced microsporidian proteasome bound by PI31-like peptides in dormant spores. Nat Commun 2022; 13:6962. [PMID: 36379934 PMCID: PMC9666519 DOI: 10.1038/s41467-022-34691-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 11/02/2022] [Indexed: 11/17/2022] Open
Abstract
Proteasomes play an essential role in the life cycle of intracellular pathogens with extracellular stages by ensuring proteostasis in environments with limited resources. In microsporidia, divergent parasites with extraordinarily streamlined genomes, the proteasome complexity and structure are unknown, which limits our understanding of how these unique pathogens adapt and compact essential eukaryotic complexes. We present cryo-electron microscopy structures of the microsporidian 20S and 26S proteasome isolated from dormant or germinated Vairimorpha necatrix spores. The discovery of PI31-like peptides, known to inhibit proteasome activity, bound simultaneously to all six active sites within the central cavity of the dormant spore proteasome, suggests reduced activity in the environmental stage. In contrast, the absence of the PI31-like peptides and the existence of 26S particles post-germination in the presence of ATP indicates that proteasomes are reactivated in nutrient-rich conditions. Structural and phylogenetic analyses reveal that microsporidian proteasomes have undergone extensive reductive evolution, lost at least two regulatory proteins, and compacted nearly every subunit. The highly derived structure of the microsporidian proteasome, and the minimized version of PI31 presented here, reinforce the feasibility of the development of specific inhibitors and provide insight into the unique evolution and biology of these medically and economically important pathogens.
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5
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Itagi P, Kante A, Lagunes L, Deeds EJ. Understanding the separation of timescales in bacterial proteasome core particle assembly. Biophys J 2022; 121:3975-3986. [PMID: 36016496 PMCID: PMC9674962 DOI: 10.1016/j.bpj.2022.08.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 08/10/2022] [Accepted: 08/19/2022] [Indexed: 11/29/2022] Open
Abstract
The 20S proteasome core particle (CP) is a molecular machine that is a key component of cellular protein degradation pathways. Like other molecular machines, it is not synthesized in an active form but rather as a set of subunits that assemble into a functional complex. The CP is conserved across all domains of life and is composed of 28 subunits, 14 α and 14 β, arranged in four stacked seven-member rings (α7β7β7α7). While details of CP assembly vary across species, the final step in the assembly process is universally conserved: two half proteasomes (HPs; α7β7) dimerize to form the CP. In the bacterium Rhodococcus erythropolis, experiments have shown that the formation of the HP is completed within minutes, while the dimerization process takes hours. The N-terminal propeptide of the β subunit, which is autocatalytically cleaved off after CP formation, plays a key role in regulating this separation of timescales. However, the detailed molecular mechanism of how the propeptide achieves this regulation is unclear. In this work, we used molecular dynamics simulations to characterize HP conformations and found that the HP exists in two states: one where the propeptide interacts with key residues in the HP dimerization interface and likely blocks dimerization, and one where this interface is free. Furthermore, we found that a propeptide mutant that dimerizes extremely slowly is essentially always in the nondimerizable state, while the wild-type rapidly transitions between the two. Based on these simulations, we designed a propeptide mutant that favored the dimerizable state in molecular dynamics simulations. In vitro assembly experiments confirmed that this mutant dimerizes significantly faster than wild-type. Our work thus provides unprecedented insight into how this critical step in CP assembly is regulated, with implications both for efforts to inhibit proteasome assembly and for the evolution of hierarchical assembly pathways.
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Affiliation(s)
- Pushpa Itagi
- Center for Computational Biology, University of Kansas, Lawrence, Kansas; Institute for Quantitative and Computational Biosciences, UCLA, Los Angeles, California
| | - Anupama Kante
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas; Department of Integrative Biology and Physiology, UCLA, Los Angeles, California
| | - Leonila Lagunes
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, California
| | - Eric J Deeds
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, California; Institute for Quantitative and Computational Biosciences, UCLA, Los Angeles, California.
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6
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Badrooh M, Shokrollahi F, Javan S, Ghasemipour T, Rezaei Mojdehi S, Farahnak H, Jahani Sayyad Noveiri M, Hedayati M, Salehzadeh A. Trigger of apoptosis in adenocarcinoma gastric cell line (AGS) by a complex of thiosemicarbazone and copper nanoparticles. Mol Biol Rep 2022; 49:2217-2226. [PMID: 35001246 DOI: 10.1007/s11033-021-07043-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 12/02/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND Seeking novel anticancer agents with minimal side effects against gastric cancer is vitally important. Copper, as an important trace element, takes roles in different physiologic pathways. Also, there is a higher demand for copper in cancer cells than normal ones. Copper complexes containing a therapeutic ligand could be promising candidates for gastric cancer chemotherapy. METHODS AND RESULTS In this work, copper oxide nanoparticles were synthesized, functionalized with glutamic acid (CuO@Glu) and conjugated with thiosemicarbazone (CuO@Glu/TSC NPs). The NPs were characterized and their antiproliferative potential against AGS cancer cells was investigated using MTT, flow cytometry, Hoechst staining, and caspase 3 activation assays. The FT-IR results showed the proper binding of TSC to CuO@Glu NPs and crystallinity of the prepared NPs was confirmed by the XRD pattern. The EDX analysis confirmed the presence of Cu, N, C, O, and S elements and lack of impurities. The Hydrodynamic size and zeta potential of the CuO@Glu/TSC NPs were 168 nm and 27.5 mV, respectively. The NPs had spherical shape and were in a size range of 10 to 60 nm in diameter. This work revealed that CuO@Glu/TSC NPs efficiently inhibited the proliferation of AGS cells with significantly lower IC50 value (203 µg/mL) than normal HEK293 cells (IC50 = 435 µg/mL). Flow cytometry and Hoechst staining obviously revealed apoptosis induction among CuO@Glu/TSC treated cells, and caspase-3 activity significantly increased by 1.4 folds. CONCLUSIONS This study introduced CuO@Glu/TSC as an efficient anticancer against gastric cancer cells with lower toxicity toward normal cells which could be employed for cancer treatment after further studies.
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Affiliation(s)
- Mahsa Badrooh
- Department of Biology, Rasht Branch, Islamic Azad University, Rasht, Iran
| | - Faezeh Shokrollahi
- Department of Biology, Rasht Branch, Islamic Azad University, Rasht, Iran
| | - Shaghayegh Javan
- Department of Medical Sciences, Faculty of Medicine, Sari Branch, Islamic Azad University, Sari, Iran
| | | | | | - Haniyeh Farahnak
- Department of Biology, Rasht Branch, Islamic Azad University, Rasht, Iran
| | | | - Mohammad Hedayati
- Pediatric Diseases Research Center, Guilan University of Medical Sciences, Rasht, Iran
| | - Ali Salehzadeh
- Department of Biology, Rasht Branch, Islamic Azad University, Rasht, Iran.
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7
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Interaction with the Assembly Chaperone Ump1 Promotes Incorporation of the β7 Subunit into Half-Proteasome Precursor Complexes Driving Their Dimerization. Biomolecules 2022; 12:biom12020253. [PMID: 35204754 PMCID: PMC8961534 DOI: 10.3390/biom12020253] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 01/29/2022] [Accepted: 02/02/2022] [Indexed: 02/04/2023] Open
Abstract
Biogenesis of the eukaryotic 20S proteasome core particle (PC) is a complex process assisted by specific chaperones absent from the active complex. The first identified chaperone, Ump1, was found in a precursor complex (PC) called 15S PC. Yeast cells lacking Ump1 display strong defects in the autocatalytic processing of β subunits, and consequently have lower proteolytic activity. Here, we dissect an important interaction of Ump1 with the β7 subunit that is critical for proteasome biogenesis. Functional domains of Ump1 and the interacting proteasome subunit β7 were mapped, and the functional consequences of their deletion or mutation were analyzed. Cells in which the first sixteen Ump1 residues were deleted display growth phenotypes similar to ump1∆, but massively accumulate 15S PC and distinct proteasome intermediate complexes containing the truncated protein. The viability of these cells depends on the transcription factor Rpn4. Remarkably, β7 subunit overexpression re-established viability in the absence of Rpn4. We show that an N-terminal domain of Ump1 and the propeptide of β7 promote direct interaction of the two polypeptides in vitro. This interaction is of critical importance for the recruitment of β7 precursor during proteasome assembly, a step that drives dimerization of 15S PCs and the formation of 20S CPs.
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8
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Tripathi SC, Vedpathak D, Ostrin EJ. The Functional and Mechanistic Roles of Immunoproteasome Subunits in Cancer. Cells 2021; 10:cells10123587. [PMID: 34944095 PMCID: PMC8700164 DOI: 10.3390/cells10123587] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 12/09/2021] [Accepted: 12/13/2021] [Indexed: 12/15/2022] Open
Abstract
Cell-mediated immunity is driven by antigenic peptide presentation on major histocompatibility complex (MHC) molecules. Specialized proteasome complexes called immunoproteasomes process viral, bacterial, and tumor antigens for presentation on MHC class I molecules, which can induce CD8 T cells to mount effective immune responses. Immunoproteasomes are distinguished by three subunits that alter the catalytic activity of the proteasome and are inducible by inflammatory stimuli such as interferon-γ (IFN-γ). This inducible activity places them in central roles in cancer, autoimmunity, and inflammation. While accelerated proteasomal degradation is an important tumorigenic mechanism deployed by several cancers, there is some ambiguity regarding the role of immunoproteasome induction in neoplastic transformation. Understanding the mechanistic and functional relevance of the immunoproteasome provides essential insights into developing targeted therapies, including overcoming resistance to standard proteasome inhibition and immunomodulation of the tumor microenvironment. In this review, we discuss the roles of the immunoproteasome in different cancers.
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Affiliation(s)
- Satyendra Chandra Tripathi
- Department of Biochemistry, All India Institute of Medical Sciences Nagpur, Nagpur 441108, MH, India;
- Correspondence: (S.C.T.); (E.J.O.)
| | - Disha Vedpathak
- Department of Biochemistry, All India Institute of Medical Sciences Nagpur, Nagpur 441108, MH, India;
| | - Edwin Justin Ostrin
- Department of General Internal Medicine, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Correspondence: (S.C.T.); (E.J.O.)
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9
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Probing allosteric interactions in homo-oligomeric molecular machines using solution NMR spectroscopy. Proc Natl Acad Sci U S A 2021; 118:2116325118. [PMID: 34893543 DOI: 10.1073/pnas.2116325118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2021] [Indexed: 11/18/2022] Open
Abstract
Developments in solution NMR spectroscopy have significantly impacted the biological questions that can now be addressed by this methodology. By means of illustration, we present here a perspective focusing on studies of a number of molecular machines that are critical for cellular homeostasis. The role of NMR in elucidating the structural dynamics of these important molecules is emphasized, focusing specifically on intersubunit allosteric communication in homo-oligomers. In many biophysical studies of oligomers, allostery is inferred by showing that models specifically including intersubunit communication best fit the data of interest. Ideally, however, experimental studies focusing on one subunit of a multisubunit system would be performed as an important complement to the more traditional bulk measurements in which signals from all components are measured simultaneously. Using an approach whereby asymmetric molecules are prepared in concert with NMR experiments focusing on the structural dynamics of individual protomers, we present examples of how intersubunit allostery can be directly observed in high-molecular-weight protein systems. These examples highlight some of the unique roles of solution NMR spectroscopy in studies of complex biomolecules and emphasize the important synergy between NMR and other atomic resolution biophysical methods.
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10
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Bi M, Du X, Xiao X, Dai Y, Jiao Q, Chen X, Zhang L, Jiang H. Deficient immunoproteasome assembly drives gain of α-synuclein pathology in Parkinson's disease. Redox Biol 2021; 47:102167. [PMID: 34662812 PMCID: PMC8577461 DOI: 10.1016/j.redox.2021.102167] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 10/11/2021] [Accepted: 10/13/2021] [Indexed: 01/07/2023] Open
Abstract
Aberrant α-synuclein (α-Syn) accumulation resulting from proteasome dysfunction is considered as a prominent factor to initiate and aggravate the neurodegeneration in Parkinson's disease (PD). Although the involvement of 26S proteasome in proteostasis imbalance has been widely accepted, our knowledge about the regulation of immunoproteasome function and its potential role in α-Syn pathology remains limited. Immunoproteasome abundance and proteolytic activities depend on the finely tuned assembly process, especially β-ring formation mediated by the only well-known chaperone proteasome maturation protein (POMP). Here, we identified that α-Syn overexpression was associated with a reduction in immunoproteasome function, which in turn limited the degradation of polo-like kinase 2 (PLK2), exacerbated α-Syn Ser129 phosphorylation and aggregation, ultimately leading to the neurodegeneration. These effects could be dramatically attenuated by β5i overexpression. Mechanistically, α-Syn suppressed the transcriptional regulation of POMP by nuclear factor erythroid 2-related factor 2 (NRF2), thereby preventing the assembly of immunoproteasome β subunits. Dopaminergic neurons-specific overexpression of NRF2-POMP axis effectively rescued the aggregation of α-Syn and PD-like phenotypes. These findings characterized abnormal immunoproteasome assembly as a key contributor governing α-Syn accumulation and neurodegeneration, which might open up a new perspective for the implication of immunoproteasome in PD and provide approaches of manipulating immunoproteasome assembly for therapeutic purposes. α-Syn negatively regulated immunoproteasome by inhibiting POMP-mediated assembly. Immunoproteasome deficiency prevented PLK2 degradation to aggravate neurotoxicity. Enhanced immunoproteasome assembly via NRF2-POMP axis alleviated α-Syn pathology.
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Affiliation(s)
- Mingxia Bi
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China
| | - Xixun Du
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China
| | - Xue Xiao
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China
| | - Yingying Dai
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China
| | - Qian Jiao
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China
| | - Xi Chen
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China
| | - Lingqiang Zhang
- State Key Laboratory of Proteomics, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Hong Jiang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China.
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Abstract
Sustaining a healthy proteome is a lifelong challenge for each individual cell of an organism. However, protein homeostasis or proteostasis is constantly jeopardized since damaged proteins accumulate under proteotoxic stress that originates from ever-changing metabolic, environmental, and pathological conditions. Proteostasis is achieved via a conserved network of quality control pathways that orchestrate the biogenesis of correctly folded proteins, prevent proteins from misfolding, and remove potentially harmful proteins by selective degradation. Nevertheless, the proteostasis network has a limited capacity and its collapse deteriorates cellular functionality and organismal viability, causing metabolic, oncological, or neurodegenerative disorders. While cell-autonomous quality control mechanisms have been described intensely, recent work on Caenorhabditis elegans has demonstrated the systemic coordination of proteostasis between distinct tissues of an organism. These findings indicate the existence of intricately balanced proteostasis networks important for integration and maintenance of the organismal proteome, opening a new door to define novel therapeutic targets for protein aggregation diseases. Here, we provide an overview of individual protein quality control pathways and the systemic coordination between central proteostatic nodes. We further provide insights into the dynamic regulation of cellular and organismal proteostasis mechanisms that integrate environmental and metabolic changes. The use of C. elegans as a model has pioneered our understanding of conserved quality control mechanisms important to safeguard the organismal proteome in health and disease.
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12
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Simulating the directional translocation of a substrate by the AAA+ motor in the 26S proteasome. Proc Natl Acad Sci U S A 2021; 118:2104245118. [PMID: 34074790 DOI: 10.1073/pnas.2104245118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This work explored the molecular origin of substrate translocation by the AAA+ motor of the 26S proteasome. This exploration was performed by combining different simulation approaches including calculations of binding free energies, coarse-grained simulations, and considerations of the ATP hydrolysis energy. The simulations were used to construct the free energy landscape for the translocation process. This included the evaluation of the conformational barriers in different translocation steps. Our simulation reveals that the substrate translocation by the AAA+ motor is guided in part by electrostatic interactions. We also validated the experimental observation that bulkier residues in pore loop 1 are responsible for substrate translocation. However, our calculation also reveals that the lysine residues prior to the bulkier residues (conserved along pore loop 1) are also important for the translocation process. We believe that this computational study can help in guiding the ongoing research of the proteasome.
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13
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Bijlmakers MJ. Ubiquitination and the Proteasome as Drug Targets in Trypanosomatid Diseases. Front Chem 2021; 8:630888. [PMID: 33732684 PMCID: PMC7958763 DOI: 10.3389/fchem.2020.630888] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 12/29/2020] [Indexed: 11/13/2022] Open
Abstract
The eukaryotic pathogens Trypanosoma brucei, Trypanosoma cruzi and Leishmania are responsible for debilitating diseases that affect millions of people worldwide. The numbers of drugs available to treat these diseases, Human African Trypanosomiasis, Chagas' disease and Leishmaniasis are very limited and existing treatments have substantial shortcomings in delivery method, efficacy and safety. The identification and validation of novel drug targets opens up new opportunities for the discovery of therapeutic drugs with better efficacy and safety profiles. Here, the potential of targeting the ubiquitin-proteasome system in these parasites is reviewed. Ubiquitination is the posttranslational attachment of one or more ubiquitin proteins to substrates, an essential eukaryotic mechanism that regulates a wide variety of cellular processes in many different ways. The best studied of these is the delivery of ubiquitinated substrates for degradation to the proteasome, the major cellular protease. However, ubiquitination can also regulate substrates in proteasome-independent ways, and proteasomes can degrade proteins to some extent in ubiquitin-independent ways. Because of these widespread roles, both ubiquitination and proteasomal degradation are essential for the viability of eukaryotes and the proteins that mediate these processes are therefore attractive drug targets in trypanosomatids. Here, the current understanding of these processes in trypanosomatids is reviewed. Furthermore, significant recent progress in the development of trypanosomatid-selective proteasome inhibitors that cure mouse models of trypanosomatid infections is presented. In addition, the targeting of the key enzyme in ubiquitination, the ubiquitin E1 UBA1, is discussed as an alternative strategy. Important differences between human and trypanosomatid UBA1s in susceptibility to inhibitors predicts that the selective targeting of these enzymes in trypanosomatids may also be feasible. Finally, it is proposed that activating enzymes of the ubiquitin-like proteins SUMO and NEDD8 may represent drug targets in these trypanosomatids as well.
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Uranga J, Hasecke L, Proppe J, Fingerhut J, Mata RA. Theoretical Studies of the Acid-Base Equilibria in a Model Active Site of the Human 20S Proteasome. J Chem Inf Model 2021; 61:1942-1953. [PMID: 33719420 DOI: 10.1021/acs.jcim.0c01459] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The 20S proteasome is a macromolecule responsible for the chemical step in the ubiquitin-proteasome system of degrading unnecessary and unused proteins of the cell. It plays a central role both in the rapid growth of cancer cells and in viral infection cycles. Herein, we present a computational study of the acid-base equilibria in an active site of the human proteasome (caspase-like), an aspect which is often neglected despite the crucial role protons play in the catalysis. As example substrates, we take the inhibition by epoxy- and boronic acid-containing warheads. We have combined cluster quantum mechanical calculations, replica exchange molecular dynamics, and Bayesian optimization of nonbonded potential terms in the inhibitors. In relation to the latter, we propose an easily scalable approach for the reevaluation of nonbonded potentials making use of the hybrid quantum mechanics molecular mechanics dynamics information. Our results show that coupled acid-base equilibria need to be considered when modeling the inhibition mechanism. The coupling between a neighboring lysine and the reacting threonine is not affected by the presence of the studied inhibitors.
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Affiliation(s)
- Jon Uranga
- Institute of Physical Chemistry, University of Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Lukas Hasecke
- Institute of Physical Chemistry, University of Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Jonny Proppe
- Institute of Physical Chemistry, University of Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Jan Fingerhut
- Institute of Physical Chemistry, University of Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Ricardo A Mata
- Institute of Physical Chemistry, University of Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
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15
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Kandasamy G, Pradhan AK, Palanimurugan R. Ccr4-Not complex subunits Ccr4, Caf1, and Not4 are novel proteolysis factors promoting the degradation of ubiquitin-dependent substrates by the 26S proteasome. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119010. [PMID: 33727038 DOI: 10.1016/j.bbamcr.2021.119010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 02/16/2021] [Accepted: 03/07/2021] [Indexed: 12/22/2022]
Abstract
Degradation of short-lived and abnormal proteins is essential for normal cellular homeostasis. In eukaryotes, such unstable cellular proteins are selectively degraded by the ubiquitin proteasome system (UPS). Abnormalities in protein degradation by the UPS have been linked to several human diseases. Ccr4, Caf1, and Not4 proteins are known components of the Ccr4-Not multimeric complex. Ccr4 and Caf1 have established roles in transcription, mRNA de-adenylation and RNA degradation etc., while Not4 was shown to have important roles in regulating translation and protein quality control pathways. Here we show that Ccr4, Caf1, and Not4 have a novel function at a post-ubiquitylation step in the UPS pathway by promoting ubiquitin-dependent degradation of short-lived proteins by the 26S proteasome. Using a substrate of the well-studied ubiquitin fusion degradation (UFD) pathway, we found that its UPS-mediated degradation was severely impaired upon deletion of CCR4, CAF1, or NOT4 genes in Saccharomyces cerevisiae. Additionally, we show that Ccr4, Caf1, and Not4 bind to cellular ubiquitin conjugates, and that Ccr4 and Caf1 proteins interact with the proteasome. In contrast to Ccr4, Caf1, and Not4, other subunits of the Ccr4-Not complex are dispensable for UFD substrate degradation. From our findings we conclude that the Ccr4-Not complex subunits Ccr4, Caf1, and Not4 have a novel function outside of the canonical Ccr4-Not complex as a factor targeting ubiquitylated substrates for proteasomal degradation.
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Affiliation(s)
- Ganapathi Kandasamy
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Telangana, India.
| | - Ashis Kumar Pradhan
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Telangana, India
| | - R Palanimurugan
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Telangana, India
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16
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Serrano-Aparicio N, Moliner V, Świderek K. Nature of Irreversible Inhibition of Human 20S Proteasome by Salinosporamide A. The Critical Role of Lys–Asp Dyad Revealed from Electrostatic Effects Analysis. ACS Catal 2021. [DOI: 10.1021/acscatal.0c05313] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
| | - Vicent Moliner
- Departament de Química Física i Analítica, Universitat Jaume I, 12071 Castellón, Spain
| | - Katarzyna Świderek
- Departament de Química Física i Analítica, Universitat Jaume I, 12071 Castellón, Spain
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17
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Burris A, Waite KA, Reuter Z, Ockerhausen S, Roelofs J. Proteasome activator Blm10 levels and autophagic degradation directly impact the proteasome landscape. J Biol Chem 2021; 296:100468. [PMID: 33639167 PMCID: PMC8039559 DOI: 10.1016/j.jbc.2021.100468] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 02/12/2021] [Accepted: 02/23/2021] [Indexed: 12/09/2022] Open
Abstract
The proteasome selectively degrades proteins. It consists of a core particle (CP), which contains proteolytic active sites that can associate with different regulators to form various complexes. How these different complexes are regulated and affected by changing physiological conditions, however, remains poorly understood. In this study, we focused on the activator Blm10 and the regulatory particle (RP). In yeast, increased expression of Blm10 outcompeted RP for CP binding, which suggests that controlling the cellular levels of Blm10 can affect the relative amounts of RP-bound CP. While strong overexpression of BLM10 almost eliminated the presence of RP-CP complexes, the phenotypes this should induce were not observed. Our results show this was due to the induction of Blm10-CP autophagy under prolonged growth in YPD. Similarly, under conditions of endogenous BLM10 expression, Blm10 was degraded through autophagy as well. This suggests that reducing the levels of Blm10 allows for more CP-binding surfaces and the formation of RP-CP complexes under nutrient stress. This work provides important insights into maintaining the proteasome landscape and how protein expression levels affect proteasome function.
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Affiliation(s)
- Alicia Burris
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, USA; Molecular, Cellular, and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Kenrick A Waite
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Zachary Reuter
- Molecular, Cellular, and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Samuel Ockerhausen
- Molecular, Cellular, and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Jeroen Roelofs
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, USA; Molecular, Cellular, and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, Kansas, USA.
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18
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Santoro AM, D’Urso A, Cunsolo A, Milardi D, Purrello R, Sbardella D, Tundo GR, Diana D, Fattorusso R, Dato AD, Paladino A, Persico M, Coletta M, Fattorusso C. Cooperative Binding of the Cationic Porphyrin Tris-T4 Enhances Catalytic Activity of 20S Proteasome Unveiling a Complex Distribution of Functional States. Int J Mol Sci 2020; 21:ijms21197190. [PMID: 33003385 PMCID: PMC7582714 DOI: 10.3390/ijms21197190] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/13/2020] [Accepted: 09/23/2020] [Indexed: 12/17/2022] Open
Abstract
The present study provides new evidence that cationic porphyrins may be considered as tunable platforms to interfere with the structural “key code” present on the 20S proteasome α-rings and, by consequence, with its catalytic activity. Here, we describe the functional and conformational effects on the 20S proteasome induced by the cooperative binding of the tri-cationic 5-(phenyl)-10,15,20-(tri N-methyl-4-pyridyl) porphyrin (Tris-T4). Our integrated kinetic, NMR, and in silico analysis allowed us to disclose a complex effect on the 20S catalytic activity depending on substrate/porphyrin concentration. The analysis of the kinetic data shows that Tris-T4 shifts the relative populations of the multiple interconverting 20S proteasome conformations leading to an increase in substrate hydrolysis by an allosteric pathway. Based on our Tris-T4/h20S interaction model, Tris-T4 is able to affect gating dynamics and substrate hydrolysis by binding to an array of negatively charged and hydrophobic residues present on the protein surface involved in the 20S molecular activation by the regulatory proteins (RPs). Accordingly, despite the fact that Tris-T4 also binds to the α3ΔN mutant, allosteric modulation is not observed since the molecular mechanism connecting gate dynamics with substrate hydrolysis is impaired. We envisage that the dynamic view of the 20S conformational equilibria, activated through cooperative Tris-T4 binding, may work as a simplified model for a better understanding of the intricate network of 20S conformational/functional states that may be mobilized by exogenous ligands, paving the way for the development of a new generation of proteasome allosteric modulators.
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Affiliation(s)
- Anna Maria Santoro
- Istituto di Cristallografia—CNR Sede Secondaria di Catania, Via P. Gaifami 9/18, 95126 Catania, Italy; (A.M.S.); (D.M.)
| | - Alessandro D’Urso
- Dipartimento di Scienze Chimiche, Università Degli Studi di Catania, Viale A. Doria 6, 95125 Catania, Italy; (A.D.); (A.C.); (R.P.)
| | - Alessandra Cunsolo
- Dipartimento di Scienze Chimiche, Università Degli Studi di Catania, Viale A. Doria 6, 95125 Catania, Italy; (A.D.); (A.C.); (R.P.)
- Department of Molecular Medicine, The University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78245, USA
| | - Danilo Milardi
- Istituto di Cristallografia—CNR Sede Secondaria di Catania, Via P. Gaifami 9/18, 95126 Catania, Italy; (A.M.S.); (D.M.)
| | - Roberto Purrello
- Dipartimento di Scienze Chimiche, Università Degli Studi di Catania, Viale A. Doria 6, 95125 Catania, Italy; (A.D.); (A.C.); (R.P.)
| | - Diego Sbardella
- IRCCS-Fondazione Bietti, 00198 Rome, Italy; (D.S.); (G.R.T.)
| | - Grazia R. Tundo
- IRCCS-Fondazione Bietti, 00198 Rome, Italy; (D.S.); (G.R.T.)
| | - Donatella Diana
- Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, 80134 Napoli, Italy;
| | - Roberto Fattorusso
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli” Via Vivaldi 43, 81100 Caserta, Italy;
| | - Antonio Di Dato
- Dipartimento di Farmacia, Università di Napoli “Federico II”, Via D. Montesano 49, 80131 Napoli, Italy; (A.D.D.); (M.P.)
| | - Antonella Paladino
- Istituto di Chimica del Riconoscimento Molecolare, CNR, Via M. Bianco 9, 20131 Milano, Italy;
| | - Marco Persico
- Dipartimento di Farmacia, Università di Napoli “Federico II”, Via D. Montesano 49, 80131 Napoli, Italy; (A.D.D.); (M.P.)
- Centro Interuniversitario di Ricerca sulla Malaria/Italian Malaria Network, 80131 Napoli, Italy
| | - Massimo Coletta
- Dipartimento di Scienze Cliniche e Medicina Traslazionale, Università di Roma Tor Vergata, Via Montpellier 1, 00133 Roma, Italy
- Correspondence: (M.C.); (C.F.); Tel.: +39-06-72596365 (M.C.); +39-081-678544 (C.F.)
| | - Caterina Fattorusso
- Dipartimento di Farmacia, Università di Napoli “Federico II”, Via D. Montesano 49, 80131 Napoli, Italy; (A.D.D.); (M.P.)
- Centro Interuniversitario di Ricerca sulla Malaria/Italian Malaria Network, 80131 Napoli, Italy
- Correspondence: (M.C.); (C.F.); Tel.: +39-06-72596365 (M.C.); +39-081-678544 (C.F.)
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19
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Tundo GR, Sbardella D, Santoro AM, Coletta A, Oddone F, Grasso G, Milardi D, Lacal PM, Marini S, Purrello R, Graziani G, Coletta M. The proteasome as a druggable target with multiple therapeutic potentialities: Cutting and non-cutting edges. Pharmacol Ther 2020; 213:107579. [PMID: 32442437 PMCID: PMC7236745 DOI: 10.1016/j.pharmthera.2020.107579] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 05/05/2020] [Indexed: 01/10/2023]
Abstract
Ubiquitin Proteasome System (UPS) is an adaptable and finely tuned system that sustains proteostasis network under a large variety of physiopathological conditions. Its dysregulation is often associated with the onset and progression of human diseases; hence, UPS modulation has emerged as a promising new avenue for the development of treatments of several relevant pathologies, such as cancer and neurodegeneration. The clinical interest in proteasome inhibition has considerably increased after the FDA approval in 2003 of bortezomib for relapsed/refractory multiple myeloma, which is now used in the front-line setting. Thereafter, two other proteasome inhibitors (carfilzomib and ixazomib), designed to overcome resistance to bortezomib, have been approved for treatment-experienced patients, and a variety of novel inhibitors are currently under preclinical and clinical investigation not only for haematological malignancies but also for solid tumours. However, since UPS collapse leads to toxic misfolded proteins accumulation, proteasome is attracting even more interest as a target for the care of neurodegenerative diseases, which are sustained by UPS impairment. Thus, conceptually, proteasome activation represents an innovative and largely unexplored target for drug development. According to a multidisciplinary approach, spanning from chemistry, biochemistry, molecular biology to pharmacology, this review will summarize the most recent available literature regarding different aspects of proteasome biology, focusing on structure, function and regulation of proteasome in physiological and pathological processes, mostly cancer and neurodegenerative diseases, connecting biochemical features and clinical studies of proteasome targeting drugs.
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Affiliation(s)
- G R Tundo
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy.
| | | | - A M Santoro
- CNR, Institute of Crystallography, Catania, Italy
| | - A Coletta
- Department of Chemistry, University of Aarhus, Aarhus, Denmark
| | - F Oddone
- IRCCS-Fondazione Bietti, Rome, Italy
| | - G Grasso
- Department of Chemical Sciences, University of Catania, Catania, Italy
| | - D Milardi
- CNR, Institute of Crystallography, Catania, Italy
| | - P M Lacal
- Laboratory of Molecular Oncology, IDI-IRCCS, Rome, Italy
| | - S Marini
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy
| | - R Purrello
- Department of Chemical Sciences, University of Catania, Catania, Italy
| | - G Graziani
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy.
| | - M Coletta
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy.
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20
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Saha A, Oanca G, Mondal D, Warshel A. Exploring the Proteolysis Mechanism of the Proteasomes. J Phys Chem B 2020; 124:5626-5635. [PMID: 32498514 DOI: 10.1021/acs.jpcb.0c04435] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The proteasome is a key protease in the eukaryotic cells which is responsible for various important cellular processes such as the control of the cell cycle, immune responses, protein homeostasis, inflammation, apoptosis, and the response to proteotoxic stress. Acting as a major molecular machine for protein degradation, proteasome first identifies damaged or obsolete regulatory proteins by attaching ubiquitin chains and subsequently utilizes conserved pore loops of the heterohexameric ring of AAA+ (ATPases associated with diverse cellular activities) to pull and mechanically unfold and translocate the misfolded protein to the active site for proteolysis. A detailed knowledge of the reaction mechanism for this proteasomal proteolysis is of central importance, both for fundamental understanding and for drug discovery. The present study investigates the mechanism of the proteolysis by the proteasome with full consideration of the protein's flexibility and its impact on the reaction free energy. Major attention is paid to the role of the protein electrostatics in determining the activation barriers. The reaction mechanism is studied by considering a small artificial fluorogenic peptide substrate (Suc-LLVY-AMC) and evaluating the activation barriers and reaction free energies for the acylation and deacylation steps, by using the empirical valence bond method. Our results shed light on the proteolysis mechanism and thus should be important for further studies of the proteasome action.
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Affiliation(s)
- Arjun Saha
- Department of Chemistry, University of Southern California, 418 SGM Building, 3620 McClintock Ave., Los Angeles, California 90089-1062, United States
| | - Gabriel Oanca
- Department of Chemistry, University of Southern California, 418 SGM Building, 3620 McClintock Ave., Los Angeles, California 90089-1062, United States
| | - Dibyendu Mondal
- Department of Chemistry, University of Southern California, 418 SGM Building, 3620 McClintock Ave., Los Angeles, California 90089-1062, United States
| | - Arieh Warshel
- Department of Chemistry, University of Southern California, 418 SGM Building, 3620 McClintock Ave., Los Angeles, California 90089-1062, United States
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21
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Santoro AM, Lanza V, Bellia F, Sbardella D, Tundo GR, Cannizzo A, Grasso G, Arizzi M, Nicoletti VG, Alcaro S, Costa G, Pietropaolo A, Malgieri G, D'Abrosca G, Fattorusso R, García‐Viñuales S, Ahmed IMM, Coletta M, Milardi D. Pyrazolones Activate the Proteasome by Gating Mechanisms and Protect Neuronal Cells from β‐Amyloid Toxicity. ChemMedChem 2019; 15:302-316. [DOI: 10.1002/cmdc.201900612] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/28/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Anna Maria Santoro
- Consiglio Nazionale delle Ricerche Istituto di Cristallografia Via P. Gaifami 18 95126 Catania Italy
| | - Valeria Lanza
- Consiglio Nazionale delle Ricerche Istituto di Cristallografia Via P. Gaifami 18 95126 Catania Italy
| | - Francesco Bellia
- Consiglio Nazionale delle Ricerche Istituto di Cristallografia Via P. Gaifami 18 95126 Catania Italy
| | - Diego Sbardella
- IRCCS – Fondazione G.B. Bietti Via Livenza 3 00189 Roma Italy
- Università di Roma Tor Vergata Dipartimento di Scienze Cliniche e Medicina Traslazionale Via Montpellier 1 00133 Roma Italy
| | - Grazia R. Tundo
- Università di Roma Tor Vergata Dipartimento di Scienze Cliniche e Medicina Traslazionale Via Montpellier 1 00133 Roma Italy
| | - Alessandra Cannizzo
- Università degli Studi di Catania Dipartimento di Scienze Chimiche V.le Andrea Doria 6 95125 Catania Italy
| | - Giuseppe Grasso
- Università degli Studi di Catania Dipartimento di Scienze Chimiche V.le Andrea Doria 6 95125 Catania Italy
| | - Mariaconcetta Arizzi
- Università degli Studi di Catania Dipartimento di Scienze Chimiche V.le Andrea Doria 6 95125 Catania Italy
| | - Vincenzo G. Nicoletti
- Università degli Studi di Catania Dipartimento di Scienze Biomediche e Biotecnologiche (BIOMETEC) Università di Catania Via Santa Sofia 97 95124 Catania
| | - Stefano Alcaro
- Università degli Studi Magna Graecia di Catanzaro Dipartimento di Scienze della Salute Viale Europa 88100 Catanzaro Italy
| | - Giosuè Costa
- Università degli Studi Magna Graecia di Catanzaro Dipartimento di Scienze della Salute Viale Europa 88100 Catanzaro Italy
| | - Adriana Pietropaolo
- Università degli Studi Magna Graecia di Catanzaro Dipartimento di Scienze della Salute Viale Europa 88100 Catanzaro Italy
| | - Gaetano Malgieri
- Università della Campania “Luigi Vanvitelli” Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche Via Vivaldi 43 81100 Caserta Italy
| | - Gianluca D'Abrosca
- Università della Campania “Luigi Vanvitelli” Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche Via Vivaldi 43 81100 Caserta Italy
| | - Roberto Fattorusso
- Università della Campania “Luigi Vanvitelli” Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche Via Vivaldi 43 81100 Caserta Italy
| | - Sara García‐Viñuales
- Consiglio Nazionale delle Ricerche Istituto di Cristallografia Via P. Gaifami 18 95126 Catania Italy
| | - Ikhlas M. M. Ahmed
- Consiglio Nazionale delle Ricerche Istituto di Cristallografia Via P. Gaifami 18 95126 Catania Italy
| | - Massimiliano Coletta
- Università di Roma Tor Vergata Dipartimento di Scienze Cliniche e Medicina Traslazionale Via Montpellier 1 00133 Roma Italy
| | - Danilo Milardi
- Consiglio Nazionale delle Ricerche Istituto di Cristallografia Via P. Gaifami 18 95126 Catania Italy
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Discovery of Immunoproteasome Inhibitors Using Large-Scale Covalent Virtual Screening. Molecules 2019; 24:molecules24142590. [PMID: 31315311 PMCID: PMC6680723 DOI: 10.3390/molecules24142590] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 07/09/2019] [Accepted: 07/12/2019] [Indexed: 12/19/2022] Open
Abstract
Large-scale virtual screening of boronic acid derivatives was performed to identify nonpeptidic covalent inhibitors of the β5i subunit of the immunoproteasome. A hierarchical virtual screening cascade including noncovalent and covalent docking steps was applied to a virtual library of over 104,000 compounds. Then, 32 virtual hits were selected, out of which five were experimentally confirmed. Biophysical and biochemical tests showed micromolar binding affinity and time-dependent inhibitory potency for two compounds. These results validate the computational protocol that allows the screening of large compound collections. One of the lead-like boronic acid derivatives identified as a covalent immunoproteasome inhibitor is a suitable starting point for chemical optimization.
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23
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Sun C, Mo M, Wang Y, Yu W, Song C, Wang X, Chen S, Liu Y. Activation of the immunoproteasome protects SH-SY5Y cells from the toxicity of rotenone. Neurotoxicology 2019; 73:112-119. [PMID: 30904435 DOI: 10.1016/j.neuro.2019.03.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 03/13/2019] [Accepted: 03/18/2019] [Indexed: 02/06/2023]
Abstract
This study investigated the expression and role of immunoproteasome (i-proteasome) in a cell model of Parkinson's disease (PD). The cytotoxicity of rotenone was measured by CCK-8 assay. The i-proteasome β1i subunit PSMB9 was suppressed by a specific shRNA or transfected with an overexpression plasmid in the SH-SY5Y cells. Under the exposure to rotenone or not, the expression of constitutive proteasome β subunits, i-proteasome βi subunits, antigen presentation related proteins, α-syn and TH were detected by Western blot in PSMB9-silenced or -overexpressed cells, and the proteasomal activities were detected by fluorogenic peptide substrates. The location of i-proteasome βi subunits and α-syn were detected by immunofluorescence staining. The levels of ROS, GSH and MDA were measured by commercial kits. Cell apoptosis was detected by flow cytometry. Besides impairing the constitutive proteasomes, rotenone induced the expression of βi subunits of i-proteasome and antigen presentation related proteins such as TAP1, TAP2 and MHC-I. Silencing or overexpressing PSMB9 had no obvious effect on the levels of other subunits, but could regulate the chymotrypsin-like activity of 20S proteasome and the expression of TAP1, TAP2 and MHC-I. Three βi subunits (PSMB9, PSMB10, PSMB8) of i-proteasome were all co-localized with α-syn. PSMB9 knockdown aggravated accumulation of α-syn, degradation of TH, release of ROS, increased level of MDA, decreased level of GSH and eventually promoted apoptosis in SH-SY5Y cells after rotenone treatment, while over-expression of PSMB9 could attenuate these toxic effects of rotenone. I-proteasome is activated in SH-SY5Y cells treated with rotenone and may play a neuroprotective role.
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Affiliation(s)
- Congcong Sun
- Department of Neurology, Qilu Hospital of Shandong University, Jinan, 250012, China
| | - Mingshu Mo
- Department of Neurology, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510120, China
| | - Yun Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, 221000, China
| | - Wenfei Yu
- Department of Neurology, Qilu Hospital of Shandong University, Jinan, 250012, China
| | - Chengyuan Song
- Department of Neurology, Qilu Hospital of Shandong University, Jinan, 250012, China
| | - Xingbang Wang
- Department of Neurology, Qilu Hospital of Shandong University, Jinan, 250012, China
| | - Si Chen
- Department of Neurology, Qilu Hospital of Shandong University, Jinan, 250012, China
| | - Yiming Liu
- Department of Neurology, Qilu Hospital of Shandong University, Jinan, 250012, China; Brain Science Research Institute, Shandong University, Jinan, 250012, China.
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24
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Theoretical study of the inhibition mechanism of human 20S proteasome by dihydroeponemycin. Eur J Med Chem 2019; 164:399-407. [DOI: 10.1016/j.ejmech.2018.12.062] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 12/12/2018] [Accepted: 12/24/2018] [Indexed: 01/10/2023]
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25
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Kim J, Thomas CA, Ewald JM, Kurien NM, Booker ME, Greve HJ, Albu TV. Studies on lysozyme modifications induced by substituted p-benzoquinones. Bioorg Chem 2019; 85:386-398. [PMID: 30665033 DOI: 10.1016/j.bioorg.2019.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/03/2019] [Accepted: 01/08/2019] [Indexed: 11/19/2022]
Abstract
Protein misfolding can facilitate a protein damaging process and makes it susceptible to a series of events such as unfolding, adduct formation, oligomerization, or aggregation. Loss of a protein's native structure may result in its biological malfunction and/or cellular toxicity that could cause associated diseases. Several factors were identified for causing structural changes of a protein, however quinone-induced protein modifications received very little attention whether for amyloidal or non-amyloidal proteins. In this paper, we report our investigation on lysozyme modifications upon treatment with selected benzoquinones (BQs), utilizing fluorescence spectroscopy including anisotropy determination, UV-Vis spectroscopy, and SDS-PAGE. Lysozyme was reacted with substituted BQs in order to examine substituent effects on protein modifications. In addition, we evaluated lysozyme modifications induced by 1,4-benzoquinone in concentration-, pH-, temperature-, and time-dependent studies. Our study shows that all BQs can readily modify lysozyme in a complex manner through adduct formation, oligomerization, polymeric aggregation, and/or fibrilization. Electrochemical properties of selected BQs were monitored using cyclic voltammetry in phosphate buffered aqueous solution, and it was found that quinone reduction potentials correlate well with their reactivity trend toward lysozyme.
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Affiliation(s)
- Jisook Kim
- Department of Chemistry and Physics, University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA.
| | - Charles A Thomas
- Department of Chemistry and Physics, University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA
| | - Jacob M Ewald
- Department of Chemistry and Physics, University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA
| | - Neethu M Kurien
- Department of Chemistry and Physics, University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA
| | - Mary E Booker
- Department of Chemistry and Physics, University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA
| | - Hendrik J Greve
- Department of Chemistry and Physics, University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA
| | - Titus V Albu
- Department of Chemistry and Physics, University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA.
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26
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Abstract
Successful viral infection, as well as any resultant antiviral response, relies on numerous sequential interactions between host and viral factors. These interactions can take the form of affinity-based interactions between viral and host macromolecules or active, enzyme-based interactions, consisting both of direct enzyme activity performed by viral enzymes and indirect modulation of the activity of the host cell's enzymes via viral interference. This activity has the potential to transform the local microenvironment to the benefit or detriment of both the virus and the host, favouring either the continuation of the viral life cycle or the host's antiviral response. Comprehensive characterisation of enzymatic activity during viral infection is therefore necessary for the understanding of virally induced diseases. Activity-based protein profiling techniques have been established as effective and practicable tools with which to interrogate the regulation of enzymes' catalytic activity and the roles played by these enzymes in various cell processes. This paper will review the contributions of these techniques in characterising the roles of both host and viral enzymes during viral infection in humans.
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Affiliation(s)
- Benjamin F. Cravatt
- grid.214007.00000000122199231Department of Chemistry, The Scripps Research Institute, La Jolla, CA USA
| | - Ku-Lung Hsu
- grid.27755.320000 0000 9136 933XDepartment of Chemistry, University of Virginia, Charlottesville, VA USA
| | - Eranthie Weerapana
- grid.208226.c0000 0004 0444 7053Department of Chemistry, Boston College, Chestnut Hill, MA USA
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27
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Voltammetric and atomic force microscopy characterization of chymotrypsin, trypsin and caspase activities of proteasome. Catal Today 2018. [DOI: 10.1016/j.cattod.2017.01.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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28
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Defective immuno- and thymoproteasome assembly causes severe immunodeficiency. Sci Rep 2018; 8:5975. [PMID: 29654304 PMCID: PMC5899138 DOI: 10.1038/s41598-018-24199-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 03/20/2018] [Indexed: 12/22/2022] Open
Abstract
By N-ethyl-N-nitrosourea (ENU) mutagenesis, we generated the mutant mouse line TUB6 that is characterised by severe combined immunodeficiency (SCID) and systemic sterile autoinflammation in homozygotes, and a selective T cell defect in heterozygotes. The causative missense point mutation results in the single amino acid exchange G170W in multicatalytic endopeptidase complex subunit-1 (MECL-1), the β2i-subunit of the immuno- and thymoproteasome. Yeast mutagenesis and crystallographic data suggest that the severe TUB6-phenotype compared to the MECL-1 knockout mouse is caused by structural changes in the C-terminal appendage of β2i that prevent the biogenesis of immuno- and thymoproteasomes. Proteasomes are essential for cell survival, and defective proteasome assembly causes selective death of cells expressing the mutant MECL-1, leading to the severe immunological phenotype. In contrast to the immunosubunits β1i (LMP2) and β5i (LMP7), mutations in the gene encoding MECL-1 have not yet been assigned to human disorders. The TUB6 mutant mouse line exemplifies the involvement of MECL-1 in immunopathogenesis and provides the first mouse model for primary immuno- and thymoproteasome-associated immunodeficiency that may also be relevant in humans.
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29
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Alghamdi A, Vallortigara J, Howlett DR, Broadstock M, Hortobágyi T, Ballard C, Thomas AJ, O'Brien JT, Aarsland D, Attems J, Francis PT, Whitfield DR. Reduction of RPT6/S8 (a Proteasome Component) and Proteasome Activity in the Cortex is Associated with Cognitive Impairment in Lewy Body Dementia. J Alzheimers Dis 2018; 57:373-386. [PMID: 28269775 PMCID: PMC5438478 DOI: 10.3233/jad-160946] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Lewy body dementia is the second most common neurodegenerative dementia and is pathologically characterized by α-synuclein positive cytoplasmic inclusions, with varying amounts of amyloid-β (Aβ) and hyperphosphorylated tau (tau) aggregates in addition to synaptic loss. A dysfunctional ubiquitin proteasome system (UPS), the major proteolytic pathway responsible for the clearance of short lived proteins, may be a mediating factor of disease progression and of the development of α-synuclein aggregates. In the present study, protein expression of a key component of the UPS, the RPT6 subunit of the 19S regulatory complex was determined. Furthermore, the main proteolytic-like (chymotrypsin- and PGPH-) activities have also been analyzed. The middle frontal (Brodmann, BA9), inferior parietal (BA40), and anterior cingulate (BA24) gyrus' cortex were selected as regions of interest from Parkinson's disease dementia (PDD, n = 31), dementia with Lewy bodies (DLB, n = 44), Alzheimer's disease (AD, n = 16), and control (n = 24) brains. Clinical and pathological data available included the MMSE score. DLB, PDD, and AD were characterized by significant reductions of RPT6 (one-way ANOVA, p < 0.001; Bonferroni post hoc test) in prefrontal cortex and parietal cortex compared with controls. Strong associations were observed between RPT6 levels in prefrontal, parietal cortex, and anterior cingulate gyrus and cognitive impairment (p = 0.001, p = 0.001, and p = 0.008, respectively). These findings highlight the involvement of the UPS in Lewy body dementia and indicate that targeting the UPS may have the potential to slow down or reduce the progression of cognitive impairment in DLB and PDD.
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Affiliation(s)
- Amani Alghamdi
- King's College London, Wolfson Centre for Age-Related Diseases, London, UK.,Department of Biochemistry, King Saud University, College of Science, Riyadh, Saudi Arabia
| | - Julie Vallortigara
- King's College London, Wolfson Centre for Age-Related Diseases, London, UK
| | - David R Howlett
- King's College London, Wolfson Centre for Age-Related Diseases, London, UK
| | - Martin Broadstock
- King's College London, Wolfson Centre for Age-Related Diseases, London, UK
| | - Tibor Hortobágyi
- Department of Neuropathology, Institute of Pathology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Clive Ballard
- King's College London, Wolfson Centre for Age-Related Diseases, London, UK.,University of Exeter Medical School, University of Exeter, Devon, UK
| | - Alan J Thomas
- NIHR Biomedical Research Centre for Mental Health, South London and Maudsley NHS Foundation Trust and Institute of Psychiatry, Kings College London, UK
| | | | - Dag Aarsland
- Department of Neurobiology, Ward Sciences and Society, Karolinska Institute, Stockholm Sweden.,Centre for Age-Related Medicine, Stavanger University Hospital, Stavanger, Norway
| | - Johannes Attems
- Institute of Neuroscience and Newcastle University Institute for Ageing, Campus for Ageing and Vitality, UK
| | - Paul T Francis
- King's College London, Wolfson Centre for Age-Related Diseases, London, UK
| | - David R Whitfield
- King's College London, Wolfson Centre for Age-Related Diseases, London, UK
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30
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Dato AD, Cunsolo A, Persico M, Santoro AM, D'Urso A, Milardi D, Purrello R, Stefanelli M, Paolesse R, Tundo GR, Sbardella D, Fattorusso C, Coletta M. Electrostatic Map Of Proteasome α-Rings Encodes The Design of Allosteric Porphyrin-Based Inhibitors Able To Affect 20S Conformation By Cooperative Binding. Sci Rep 2017; 7:17098. [PMID: 29213119 PMCID: PMC5719074 DOI: 10.1038/s41598-017-17008-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 11/20/2017] [Indexed: 12/13/2022] Open
Abstract
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. pTMPyPP4 inhibition mechanism implies a positive cooperative binding to proteasome, which disappears when a permanently open proteasome mutant (α-3ΔN) is used, supporting the hypothesis that the events associated with allosteric proteasome inhibition by pTMPyPP4 interfere with 20S gating and affect its "open-closed" equilibrium. Therefore, we propose that the spatial distribution of the negatively charged residues responsible for the interaction with regulatory particles at the α-ring surface of human 20S may be exploited as a blueprint for the design of allosteric proteasome regulators.
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Affiliation(s)
- Antonio Di Dato
- Dipartimento di Farmacia Università di Napoli "Federico II", Via D. Montesano, 49 I, 80131, Napoli, Italy
| | - Alessandra Cunsolo
- Dipartimento di Scienze Chimiche, Università degli Studi di Catania, Viale A. Doria 6, 95125, Catania, Italy
| | - Marco Persico
- Dipartimento di Farmacia Università di Napoli "Federico II", Via D. Montesano, 49 I, 80131, Napoli, Italy
| | - Anna Maria Santoro
- Istituto di Biostrutture e Bioimmagini-CNR sede secondaria di Catania, Via P. Gaifami, 9- 95126, Catania, Italy
| | - Alessandro D'Urso
- Dipartimento di Scienze Chimiche, Università degli Studi di Catania, Viale A. Doria 6, 95125, Catania, Italy
| | - Danilo Milardi
- Istituto di Biostrutture e Bioimmagini-CNR sede secondaria di Catania, Via P. Gaifami, 9- 95126, Catania, Italy
| | - Roberto Purrello
- Dipartimento di Scienze Chimiche, Università degli Studi di Catania, Viale A. Doria 6, 95125, Catania, Italy.
| | - Manuela Stefanelli
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata-Via della Ricerca Scientifica, 00133, Roma, Italy
| | - Roberto Paolesse
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata-Via della Ricerca Scientifica, 00133, Roma, Italy
| | - Grazia R Tundo
- Dipartimento di Scienze Cliniche e Medicina Traslazionale, Università di Roma Tor Vergata, Via Montpellier 1, 00133, Roma, Italy
| | - Diego Sbardella
- Dipartimento di Scienze Cliniche e Medicina Traslazionale, Università di Roma Tor Vergata, Via Montpellier 1, 00133, Roma, Italy
| | - Caterina Fattorusso
- Dipartimento di Farmacia Università di Napoli "Federico II", Via D. Montesano, 49 I, 80131, Napoli, Italy.
| | - Massimo Coletta
- Dipartimento di Scienze Cliniche e Medicina Traslazionale, Università di Roma Tor Vergata, Via Montpellier 1, 00133, Roma, Italy.
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31
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Probing the cooperativity of Thermoplasma acidophilum proteasome core particle gating by NMR spectroscopy. Proc Natl Acad Sci U S A 2017; 114:E9846-E9854. [PMID: 29087330 DOI: 10.1073/pnas.1712297114] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The 20S proteasome core particle (20S CP) plays an integral role in cellular homeostasis by degrading proteins no longer required for function. The process is, in part, controlled via gating residues localized to the ends of the heptameric barrel-like CP structure that occlude substrate entry pores, preventing unregulated degradation of substrates that might otherwise enter the proteasome. Previously, we showed that the N-terminal residues of the α-subunits of the CP from the archaeon Thermoplasma acidophilum are arranged such that, on average, two of the seven termini are localized inside the lumen of the proteasome, thereby plugging the entry pore and functioning as a gate. However, the mechanism of gating remains unclear. Using solution NMR and a labeling procedure in which a series of mixed proteasome rings are prepared such that the percentage of gate-containing subunits is varied, we address the energetics of gating and establish whether gating is a cooperative process involving the concerted action of residues from more than a single protomer. Our results establish that the intrinsic probability of a gate entering the lumen favors the in state by close to 20-fold, that entry of each gate is noncooperative, with the number of gates that can be accommodated inside the lumen a function of the substrate entry pore size and the bulkiness of the gating residues. Insight into the origin of the high affinity for the in state is obtained from spin-relaxation experiments. More generally, our approach provides an avenue for dissecting interactions of individual protomers in homo-oligomeric complexes.
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32
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Pokrzywa W, Lorenz R, Hoppe T. Chaperone-directed ubiquitylation maintains proteostasis at the expense of longevity. WORM 2017; 6:e1371403. [PMID: 28959501 PMCID: PMC5612283 DOI: 10.1080/21624054.2017.1371403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 08/18/2017] [Indexed: 11/24/2022]
Abstract
The integrity of the cellular proteome is supported by quality control networks, which govern protein synthesis, folding, and degradation. It is generally accepted that an age-related decline in protein homeostasis (proteostasis) contributes to protein aggregation diseases. However, the mechanistic principles underlying proteostasis imbalance and the impact on life expectancy are not well understood. We recently demonstrated that this interrelation is affected by chaperone-directed ubiquitylation, shifting the amount of the conserved DAF-2/insulin receptor both in Caenorhabditis elegans and Drosophila melanogaster. The ubiquitin ligase CHIP either targets the membrane bound insulin receptor or misfolded proteins for degradation, which depends on the cellular proteostasis status. Increased proteotoxicity triggers chaperone-assisted redirection of CHIP toward protein aggregates, limiting its capacity to degrade the insulin receptor and prevent premature aging. In light of these findings, we discuss a new concept for understanding the impact of proteome imbalance on longevity risk.
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Affiliation(s)
- Wojciech Pokrzywa
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Robin Lorenz
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Thorsten Hoppe
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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33
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Ettari R, Zappalà M, Grasso S, Musolino C, Innao V, Allegra A. Immunoproteasome-selective and non-selective inhibitors: A promising approach for the treatment of multiple myeloma. Pharmacol Ther 2017; 182:176-192. [PMID: 28911826 DOI: 10.1016/j.pharmthera.2017.09.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The ubiquitin-proteasome system (UPS) is the major non-lysosomal proteolytic system for the degradation of abnormal or damaged proteins no longer required. The proteasome is involved in degradation of numerous proteins which regulate the cell cycle, indicating a role in controlling cell proliferation and maintaining cell survival. Defects in the UPS can lead to anarchic cell proliferation and to tumor development. For these reasons UPS inhibition has become a significant new strategy for drug development in cancer treatment. In addition to the constitutive proteasome, which is expressed in all cells and tissues, higher organisms such as vertebrates possess two immune-type proteasomes, the thymoproteasome and the immunoproteasome. The thymoproteasome is specifically expressed by thymic cortical epithelial cells and has a role in positive selection of CD8+ T cells, whereas the immunoproteasome is predominantly expressed in monocytes and lymphocytes and is responsible for the generation of antigenic peptides for cell-mediated immunity. Recent studies demonstrated that the immunoproteasome has a preservative role during oxidative stress and is up-regulated in a number of pathological disorders including cancer, inflammatory and autoimmune diseases. As a consequence, immunoproteasome-selective inhibitors are currently the focus of anticancer drug design. At present, the commercially available proteasome inhibitors bortezomib and carfilzomib which have been validated in multiple myeloma and other model systems, appear to target both the constitutive and immunoproteasomes, indiscriminately. This lack of specificity may, in part, explain some of the side effects of these agents, such as peripheral neuropathy and gastrointestinal effects, which may be due to targeting of the constitutive proteasome in these tissues. In contrast, by selectively inhibiting the immunoproteasome, it may be possible to maintain the antimyeloma and antilymphoma efficacy while reducing these toxicities, thereby increasing the therapeutic index. This review article will be focused on the discussion of the most promising immunoproteasome specific inhibitors which have been developed in recent years. Particular attention will be devoted to the description of their mechanism of action, their structure-activity relationship, and their potential application in therapy.
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Affiliation(s)
- Roberta Ettari
- Dipartimento di Scienze del Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Viale Annunziata, 98168 Messina, Italy
| | - Maria Zappalà
- Dipartimento di Scienze del Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Viale Annunziata, 98168 Messina, Italy
| | - Silvana Grasso
- Dipartimento di Scienze del Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Viale Annunziata, 98168 Messina, Italy
| | - Caterina Musolino
- Division of Hematology, Department of Patologia Umana dell'Adulto e dell'Età Evolutiva, University of Messina, Via Consolare Valeria, 90100 Messina, Italy
| | - Vanessa Innao
- Division of Hematology, Department of Patologia Umana dell'Adulto e dell'Età Evolutiva, University of Messina, Via Consolare Valeria, 90100 Messina, Italy
| | - Alessandro Allegra
- Division of Hematology, Department of Patologia Umana dell'Adulto e dell'Età Evolutiva, University of Messina, Via Consolare Valeria, 90100 Messina, Italy.
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34
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Moritz KE, McCormack NM, Abera MB, Viollet C, Yauger YJ, Sukumar G, Dalgard CL, Burnett BG. The role of the immunoproteasome in interferon-γ-mediated microglial activation. Sci Rep 2017; 7:9365. [PMID: 28839214 PMCID: PMC5571106 DOI: 10.1038/s41598-017-09715-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/14/2017] [Indexed: 11/12/2022] Open
Abstract
Microglia regulate the brain microenvironment by sensing damage and neutralizing potentially harmful insults. Disruption of central nervous system (CNS) homeostasis results in transition of microglia to a reactive state characterized by morphological changes and production of cytokines to prevent further damage to CNS tissue. Immunoproteasome levels are elevated in activated microglia in models of stroke, infection and traumatic brain injury, though the exact role of the immunoproteasome in neuropathology remains poorly defined. Using gene expression analysis and native gel electrophoresis we characterize the expression and assembly of the immunoproteasome in microglia following interferon-gamma exposure. Transcriptome analysis suggests that the immunoproteasome regulates multiple features of microglial activation including nitric oxide production and phagocytosis. We show that inhibiting the immunoproteasome attenuates expression of pro-inflammatory cytokines and suppresses interferon-gamma-dependent priming of microglia. These results imply that targeting immunoproteasome function following CNS injury may attenuate select microglial activity to improve the pathophysiology of neurodegenerative conditions or the progress of inflammation-mediated secondary injury following neurotrauma.
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Affiliation(s)
- Kasey E Moritz
- Neuroscience Program, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD, USA
| | - Nikki M McCormack
- Neuroscience Program, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD, USA
| | - Mahlet B Abera
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Coralie Viollet
- Collaborative Health Initiative Research Program, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Young J Yauger
- Neuroscience Program, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD, USA
| | - Gauthaman Sukumar
- Collaborative Health Initiative Research Program, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Clifton L Dalgard
- Neuroscience Program, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD, USA.,Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.,Collaborative Health Initiative Research Program, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.,The American Genome Center, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Barrington G Burnett
- Neuroscience Program, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD, USA. .,Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
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35
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Abstract
This brief disquisition about the early history of studies on regulated protein degradation introduces several detailed reviews about the ubiquitin system and autophagy.
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Affiliation(s)
- Alexander Varshavsky
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125;
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36
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The Architecture of the Anbu Complex Reflects an Evolutionary Intermediate at the Origin of the Proteasome System. Structure 2017; 25:834-845.e5. [PMID: 28479063 PMCID: PMC5666114 DOI: 10.1016/j.str.2017.04.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 12/23/2016] [Accepted: 04/14/2017] [Indexed: 11/22/2022]
Abstract
Proteasomes are self-compartmentalizing proteases that function at the core of the cellular protein degradation machinery in eukaryotes, archaea, and some bacteria. Although their evolutionary history is under debate, it is thought to be linked to that of the bacterial protease HslV and the hypothetical bacterial protease Anbu (ancestral beta subunit). Here, together with an extensive bioinformatic analysis, we present the first biophysical characterization of Anbu. Anbu forms a dodecameric complex with a unique architecture that was only accessible through the combination of X-ray crystallography and small-angle X-ray scattering. While forming continuous helices in crystals and electron microscopy preparations, refinement of sections from the crystal structure against the scattering data revealed a helical open-ring structure in solution, contrasting the ring-shaped structures of proteasome and HslV. Based on this primordial architecture and exhaustive sequence comparisons, we propose that Anbu represents an ancestral precursor at the origin of self-compartmentalization. The crystal structure of the bacterial proteasome homolog Anbu has been solved The dodecameric architecture reveals unique features compared with classical proteasomes Bioinformatic analysis places Anbu at the root of the proteasome family
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37
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Bach SV, Hegde AN. The proteasome and epigenetics: zooming in on histone modifications. Biomol Concepts 2017; 7:215-27. [PMID: 27522625 DOI: 10.1515/bmc-2016-0016] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/12/2016] [Indexed: 12/11/2022] Open
Abstract
The proteasome is a structural complex of many proteins that degrades substrates marked by covalent linkage to ubiquitin. Many years of research has shown a role for ubiquitin-proteasome-mediated proteolysis in synaptic plasticity and memory mainly in degrading synaptic, cytoplasmic and nuclear proteins. Recent work indicates that the proteasome has wider proteolytic and non-proteolytic roles in processes such as histone modifications that affect synaptic plasticity and memory. In this review, we assess the evidence gathered from neuronal as well as non-neuronal cell types regarding the function of the proteasome in positive or negative regulation of posttranslational modifications of histones, such as acetylation, methylation and ubiquitination. We discuss the critical roles of the proteasome in clearing excess histone proteins in various cellular contexts and the possible non-proteolytic functions in regulating transcription of target genes. In addition, we summarize the current literature on diverse chromatin-remodeling machineries, such as histone acetyltransferases, deacetylates, methyltransferases and demethylases, as targets for proteasomal degradation across experimental models. Lastly, we provide a perspective on how proteasomal regulation of histone modifications may modulate synaptic plasticity in the nervous system.
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38
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α-Chymotrypsin regulates free fatty acids and UCHL-1 to ameliorate N-methyl nitrosourea induced mammary gland carcinoma in albino wistar rats. Inflammopharmacology 2016; 24:277-286. [PMID: 27671329 DOI: 10.1007/s10787-016-0280-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 09/06/2016] [Indexed: 02/06/2023]
Abstract
This study was undertaken to investigate the effect of α-chymotrypsin on methyl nitrosourea (MNU) induced mammary gland carcinoma in albino wistar rats. Animals were randomized into four groups (six animals in each). Group I (sham control 0.9 % normal saline p.o.); Group II (toxic control, MNU 47 mg/kg, i.v.); Group III (α-chymotrypsin, 5 mg/kg, p.o.); Group IV (α-chymotrypsin, 10 mg/kg p.o.). Toxicity was induced by single i.v. injection of MNU followed by α-chymotrypsin supplementation therapy for 100 days. MNU treatment was evident with increased alveolar bud count, differentiation score, upregulated inflammatory enzymes markers (COX, LOX and NO) antioxidative stress markers (TBARs, SOD, catalase and GSH).MNU associated toxicity was also ascertained by PGP 9.5 and NF-κB expression in the mammary gland tissue followed by FAME analysis for fatty acid profiling. α-chymotrypsin afforded significant protection against the deleterious effects of MNU.
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39
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Hegde AN. Proteolysis, synaptic plasticity and memory. Neurobiol Learn Mem 2016; 138:98-110. [PMID: 27614141 DOI: 10.1016/j.nlm.2016.09.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 08/25/2016] [Accepted: 09/05/2016] [Indexed: 12/30/2022]
Abstract
Protein degradation has many critical functions in the nervous system such as refinement of synaptic connections during development and synaptic plasticity and memory in the adult organisms. A major cellular machinery of proteolysis is the ubiquitin-proteasome pathway (UPP). The UPP precisely regulates proteolysis by covalently attaching ubiquitin, a small protein, to substrates through sequential enzymatic reactions and the proteins marked with the ubiquitin tag are degraded by complex containing many subunits called the proteasome. Research over the years has shown a role for the UPP in regulating presynaptic and postsynaptic proteins critical for neurotransmission and synaptic plasticity. Studies have also revealed a role for the UPP in various forms of memory. Mechanistic investigations suggest that the function of the UPP in neurons is not homogenous and is subject to local regulation in different neuronal sub-compartments. In both invertebrate and vertebrate model systems, local roles have been found for enzymes that attach ubiquitin to substrate proteins as well as for enzymes that remove ubiquitin from substrates. The proteasome also has disparate functions in different parts of the neuron. In addition to the UPP, proteolysis by the lysosome and autophagy play a role in synaptic plasticity and memory. This review details the functions of proteolysis in synaptic plasticity and summarizes the findings on the connection between proteolysis and memory mainly focusing on the UPP including its local roles.
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Affiliation(s)
- Ashok N Hegde
- Department of Biological and Environmental Sciences, Georgia College and State University, Milledgeville, GA 31061, USA.
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40
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Shen Q, Hu T, Bao M, Cao L, Zhang H, Song F, Xie Q, Zhou X. Tobacco RING E3 Ligase NtRFP1 Mediates Ubiquitination and Proteasomal Degradation of a Geminivirus-Encoded βC1. MOLECULAR PLANT 2016; 9:911-25. [PMID: 27018391 DOI: 10.1016/j.molp.2016.03.008] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 02/17/2016] [Accepted: 03/03/2016] [Indexed: 05/19/2023]
Abstract
The βC1 protein encoded by the Tomato yellow leaf curl China virus-associated betasatellite functions as a pathogenicity determinant. To better understand the molecular basis whereby βC1 functions in pathogenicity, a yeast two-hybrid screen of a tobacco cDNA library was carried out using βC1 as the bait. The screen revealed that βC1 interacts with a tobacco RING-finger protein designated NtRFP1, which was further confirmed by the bimolecular fluorescence complementation and co-immunoprecipitation assays in Nicotiana benthamiana cells. Expression of NtRFP1 was induced by βC1, and in vitro ubiquitination assays showed that NtRFP1 is a functional E3 ubiquitin ligase that mediates βC1 ubiquitination. In addition, βC1 was shown to be ubiquitinated in vivo and degraded by the plant 26S proteasome. After viral infection, plants overexpressing NtRFP1 developed attenuated symptoms, whereas plants with silenced expression of NtRFP1 showed severe symptoms. Other lines of evidence showed that NtRFP1 attenuates βC1-induced symptoms through promoting its degradation by the 26S proteasome. Taken together, our results suggest that tobacco RING E3 ligase NtRFP1 attenuates disease symptoms by interacting with βC1 to mediate its ubiquitination and degradation via the ubiquitin/26S proteasome system.
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Affiliation(s)
- Qingtang Shen
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Tao Hu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Min Bao
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Linge Cao
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Huawei Zhang
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Fengmin Song
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Qi Xie
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Xueping Zhou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
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Semren N, Welk V, Korfei M, Keller IE, Fernandez IE, Adler H, Günther A, Eickelberg O, Meiners S. Regulation of 26S Proteasome Activity in Pulmonary Fibrosis. Am J Respir Crit Care Med 2016. [PMID: 26207697 DOI: 10.1164/rccm.201412-2270oc] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE The ubiquitin-proteasome system is critical for maintenance of protein homeostasis by degrading polyubiquitinated proteins in a spatially and temporally controlled manner. Cell and protein homeostasis are altered upon pathological tissue remodeling. Dysregulation of the proteasome has been reported for several chronic diseases of the heart, brain, and lung. We hypothesized that proteasome function is altered upon fibrotic lung remodeling, thereby contributing to the pathogenesis of idiopathic pulmonary fibrosis (IPF). OBJECTIVES To investigate proteasome function during myofibroblast differentiation. METHODS We treated lung fibroblasts with transforming growth factor (TGF)-β and examined proteasome composition and activity. For in vivo analysis, we used mouse models of lung fibrosis and fibrotic human lung tissue. MEASUREMENTS AND MAIN RESULTS We demonstrate that induction of myofibroblast differentiation by TGF-β involves activation of the 26S proteasome, which is critically dependent on the regulatory subunit Rpn6. Silencing of Rpn6 in primary human lung fibroblasts counteracted TGF-β-induced myofibroblast differentiation. Activation of the 26S proteasome and increased expression of Rpn6 were detected during bleomycin-induced lung remodeling and fibrosis. Importantly, Rpn6 is overexpressed in myofibroblasts and basal cells of the bronchiolar epithelium in lungs of patients with IPF, which is accompanied by enhanced protein polyubiquitination. CONCLUSIONS We identified Rpn6-dependent 26S proteasome activation as an essential feature of myofibroblast differentiation in vitro and in vivo, and our results suggest it has an important role in IPF pathogenesis.
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Affiliation(s)
- Nora Semren
- 1 Comprehensive Pneumology Center (CPC), University Hospital of the Ludwig-Maximilians University (LMU), LMU, Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), Munich, Germany
| | - Vanessa Welk
- 1 Comprehensive Pneumology Center (CPC), University Hospital of the Ludwig-Maximilians University (LMU), LMU, Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), Munich, Germany
| | - Martina Korfei
- 2 Department of Internal Medicine, Universities of Giessen and Marburg Lung Center (UGMLC), Justus-Liebig-University Giessen, Member of the DZL, Giessen, Germany
| | - Ilona E Keller
- 1 Comprehensive Pneumology Center (CPC), University Hospital of the Ludwig-Maximilians University (LMU), LMU, Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), Munich, Germany
| | - Isis E Fernandez
- 1 Comprehensive Pneumology Center (CPC), University Hospital of the Ludwig-Maximilians University (LMU), LMU, Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), Munich, Germany
| | - Heiko Adler
- 3 Research Unit Gene Vectors, Helmholtz Zentrum München, Munich, Germany
| | - Andreas Günther
- 2 Department of Internal Medicine, Universities of Giessen and Marburg Lung Center (UGMLC), Justus-Liebig-University Giessen, Member of the DZL, Giessen, Germany.,4 Agaplesion Lung Clinic Waldhof Elgershausen, Greifenstein, Germany; and.,5 European IPF Network and European IPF Registry, Giessen, Germany
| | - Oliver Eickelberg
- 1 Comprehensive Pneumology Center (CPC), University Hospital of the Ludwig-Maximilians University (LMU), LMU, Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), Munich, Germany
| | - Silke Meiners
- 1 Comprehensive Pneumology Center (CPC), University Hospital of the Ludwig-Maximilians University (LMU), LMU, Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), Munich, Germany
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A unified mechanism for proteolysis and autocatalytic activation in the 20S proteasome. Nat Commun 2016; 7:10900. [PMID: 26964885 PMCID: PMC4792962 DOI: 10.1038/ncomms10900] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 01/31/2016] [Indexed: 11/28/2022] Open
Abstract
Biogenesis of the 20S proteasome is tightly regulated. The N-terminal propeptides protecting the active-site threonines are autocatalytically released only on completion of assembly. However, the trigger for the self-activation and the reason for the strict conservation of threonine as the active site nucleophile remain enigmatic. Here we use mutagenesis, X-ray crystallography and biochemical assays to suggest that Lys33 initiates nucleophilic attack of the propeptide by deprotonating the Thr1 hydroxyl group and that both residues together with Asp17 are part of a catalytic triad. Substitution of Thr1 by Cys disrupts the interaction with Lys33 and inactivates the proteasome. Although a Thr1Ser mutant is active, it is less efficient compared with wild type because of the unfavourable orientation of Ser1 towards incoming substrates. This work provides insights into the basic mechanism of proteolysis and propeptide autolysis, as well as the evolutionary pressures that drove the proteasome to become a threonine protease. The proteasome, an essential molecular machine, is a threonine protease, but the evolution and the components of its proteolytic centre are unclear. Here, the authors use structural biology and biochemistry to investigate the role of proteasome active site residues on maturation and activity.
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43
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Wei D, Tang M, Zhan CG. Fundamental reaction pathway and free energy profile of proteasome inhibition by syringolin A (SylA). Org Biomol Chem 2016; 13:6857-65. [PMID: 26018983 DOI: 10.1039/c5ob00737b] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this study, molecular dynamics (MD) simulations and first-principles quantum mechanical/molecular mechanical free energy (QM/MM-FE) calculations have been performed to uncover the fundamental reaction pathway of proteasome with a representative inhibitor syringolin A (SylA). The calculated results reveal that the reaction process consists of three steps. The first step is a proton transfer process, activating Thr1-O(γ) directly by Thr1-N(z) to form a zwitterionic intermediate. The next step is a nucleophilic attack on the olefin carbon of SylA by the negatively charged Thr1-O(γ) atom. The last step is a proton transfer from Thr1-N(z) to another olefin carbon of SylA to complete the inhibition reaction process. The calculated free energy profile demonstrates that the second step should be the rate-determining step and has the highest free energy barrier of 24.6 kcal mol(-1), which is reasonably close to the activation free energy (∼22.4-23.0 kcal mol(-1)) derived from the available experimental kinetic data. In addition, our computational results indicate that no water molecule can assist the rate-determining step, since the second step is not involved in a proton transfer process. The obtained mechanistic insights should be valuable for understanding the inhibition process of proteasome by SylA and structurally related inhibitors at a molecular level, and thus provide a solid mechanistic base and valuable clues for future rational design of novel, more potent inhibitors of proteasome.
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Affiliation(s)
- Donghui Wei
- Department of Chemistry, Zhengzhou University, Daxue Road, Zhengzhou, Henan 450052, China
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44
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Li B, Fu J, Chen P, Ge X, Li Y, Kuiatse I, Wang H, Wang H, Zhang X, Orlowski RZ. The Nuclear Factor (Erythroid-derived 2)-like 2 and Proteasome Maturation Protein Axis Mediate Bortezomib Resistance in Multiple Myeloma. J Biol Chem 2015; 290:29854-68. [PMID: 26483548 DOI: 10.1074/jbc.m115.664953] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Indexed: 11/06/2022] Open
Abstract
Resistance to the proteasome inhibitor bortezomib is an emerging clinical problem whose mechanisms have not been fully elucidated. We considered the possibility that this could be associated with enhanced proteasome activity in part through the action of the proteasome maturation protein (POMP). Bortezomib-resistant myeloma models were used to examine the correlation between POMP expression and bortezomib sensitivity. POMP expression was then modulated using genetic and pharmacologic approaches to determine the effects on proteasome inhibitor sensitivity in cell lines and in vivo models. Resistant cell lines were found to overexpress POMP, and while its suppression in cell lines enhanced bortezomib sensitivity, POMP overexpression in drug-naive cells conferred resistance. Overexpression of POMP was associated with increased levels of nuclear factor (erythroid-derived 2)-like (NRF2), and NRF2 was found to bind to and activate the POMP promoter. Knockdown of NRF2 in bortezomib-resistant cells reduced POMP levels and proteasome activity, whereas its overexpression in drug-naive cells increased POMP and proteasome activity. The NRF2 inhibitor all-trans-retinoic acid reduced cellular NRF2 levels and increased the anti-proliferative and pro-apoptotic activities of bortezomib in resistant cells, while decreasing proteasome capacity. Finally, the combination of all-trans-retinoic acid with bortezomib showed enhanced activity against primary patient samples and in a murine model of bortezomib-resistant myeloma. Taken together, these studies validate a role for the NRF2/POMP axis in bortezomib resistance and identify NRF2 and POMP as potentially attractive targets for chemosensitization to this proteasome inhibitor.
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Affiliation(s)
- Bingzong Li
- From the Department of Hematology, Second Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu, China and the Departments of Lymphoma and Myeloma and
| | - Jinxiang Fu
- From the Department of Hematology, Second Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu, China and
| | - Ping Chen
- From the Department of Hematology, Second Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu, China and
| | - Xueping Ge
- From the Department of Hematology, Second Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu, China and
| | - Yali Li
- From the Department of Hematology, Second Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu, China and
| | | | - Hua Wang
- the Departments of Lymphoma and Myeloma and
| | | | | | - Robert Z Orlowski
- the Departments of Lymphoma and Myeloma and Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
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Gruba N, Wysocka M, Brzezińska M, Debowski D, Rolka K, Martin NI, Lesner A. Novel internally quenched substrate of the trypsin-like subunit of 20S eukaryotic proteasome. Anal Biochem 2015; 508:38-45. [PMID: 26314791 DOI: 10.1016/j.ab.2015.08.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 07/16/2015] [Accepted: 08/14/2015] [Indexed: 12/11/2022]
Abstract
This article describes the synthesis, using combinatorial chemistry, of internally quenched substrates of the trypsin-like subunit of human 20S proteasome. Such substrates were optimized in both the nonprime and prime regions of the peptide chain. Two were selected as the most susceptible for proteasomal proteolysis with excellent kinetic parameters: (i) ABZ-Val-Val-Ser-Arg-Ser-Leu-Gly-Tyr(3-NO2)-NH2 (kcat/KM = 934,000 M(-1) s(-1)) and (ii) ABZ-Val-Val-Ser-GNF-Ala-Met-Gly-Tyr(3-NO2)-NH2 (kcat/KM = 1,980,000 M(-1) s(-1)). Both compounds were efficiently hydrolyzed by the 20S proteasome at picomolar concentrations, demonstrating significant selectivity over other proteasome entities.
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Affiliation(s)
- Natalia Gruba
- Faculty of Chemistry, University of Gdansk, 80-308 Gdansk, Poland
| | | | | | - Dawid Debowski
- Faculty of Chemistry, University of Gdansk, 80-308 Gdansk, Poland
| | - Krzysztof Rolka
- Faculty of Chemistry, University of Gdansk, 80-308 Gdansk, Poland
| | - Nathaniel I Martin
- Faculty of Science, Utrecht University, 3512 JE Utrecht, The Netherlands
| | - Adam Lesner
- Faculty of Chemistry, University of Gdansk, 80-308 Gdansk, Poland.
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46
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Schuld NJ, Hussong SA, Kapphahn RJ, Lehmann U, Roehrich H, Rageh AA, Heuss ND, Bratten W, Gregerson DS, Ferrington DA. Immunoproteasome deficiency protects in the retina after optic nerve crush. PLoS One 2015; 10:e0126768. [PMID: 25978061 PMCID: PMC4433222 DOI: 10.1371/journal.pone.0126768] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 04/07/2015] [Indexed: 01/31/2023] Open
Abstract
The immunoproteasome is upregulated by disease, oxidative stress, and inflammatory cytokines, suggesting an expanded role for the immunoproteasome in stress signaling that goes beyond its canonical role in generating peptides for antigen presentation. The signaling pathways that are regulated by the immunoproteasome remain elusive. However, previous studies suggest a role for the immunoproteasome in the regulation of PTEN and NF-κB signaling. One well-known pathway upstream of NF-κB and downstream of PTEN is the Akt signaling pathway, which is responsible for mediating cellular survival and is modulated after optic nerve crush (ONC). This study investigated the role of retinal immunoproteasome after injury induced by ONC, focusing on the Akt cell survival pathway. Retinas or retinal pigment epithelial (RPE) cells from wild type (WT) and knockout (KO) mice lacking either one (LMP2) or two (LMP7 and MECL-1) catalytic subunits of the immunoproteasome were utilized in this study. We show that mRNA and protein levels of the immunoproteasome subunits are significantly upregulated in WT retinas following ONC. Mice lacking the immunoproteasome subunits show either a delayed or dampened apoptotic response as well as altered Akt signaling, compared to WT mice after ONC. Treatment of the RPE cells with insulin growth factor-1 (IGF-1) to stimulate Akt signaling confirmed that the immunoproteasome modulates this pathway, and most likely modulates parallel pathways as well. This study links the inducible expression of the immunoproteasome following retinal injury to Akt signaling, which is important in many disease pathways.
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Affiliation(s)
- Nathan J. Schuld
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Stacy A. Hussong
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
- Graduate Program in Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Rebecca J. Kapphahn
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Ute Lehmann
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
- Graduate Program in Microbiology, Immunology and Cancer Biology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Heidi Roehrich
- Histology Core for Vision Research, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Abrar A. Rageh
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Neal D. Heuss
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Wendy Bratten
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Dale S. Gregerson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Deborah A. Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail:
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Wani PS, Rowland MA, Ondracek A, Deeds EJ, Roelofs J. Maturation of the proteasome core particle induces an affinity switch that controls regulatory particle association. Nat Commun 2015; 6:6384. [PMID: 25812915 PMCID: PMC4380239 DOI: 10.1038/ncomms7384] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 01/25/2015] [Indexed: 01/09/2023] Open
Abstract
Proteasome assembly is a complex process, requiring 66 subunits distributed over several subcomplexes to associate in a coordinated fashion. Ten proteasome-specific chaperones have been identified that assist in this process. For two of these, the Pba1-Pba2 dimer, it is well established that they only bind immature core particles (CP) in vivo. In contrast, the regulatory particle (RP) utilizes the same binding surface but only interacts with the mature CP in vivo. It is unclear how these binding events are regulated. Here, we show that Pba1-Pba2 binds tightly to immature CP, preventing RP binding. Changes in the CP that occur upon maturation significantly reduce its affinity for Pba1-Pba2, enabling the RP to displace the chaperone. Mathematical modeling indicates that this “affinity switch” mechanism has likely evolved to improve assembly efficiency by preventing the accumulation of stable, non-productive intermediates. Our work thus provides mechanistic insights into a crucial step in proteasome biogenesis.
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Affiliation(s)
- Prashant S Wani
- Graduate Biochemistry Group, Department of Biochemistry and Molecular Biophysics, Kansas State University, 336 Ackert Hall, Manhattan, Kansas 66506, USA
| | - Michael A Rowland
- Center for Computational Biology, University of Kansas, 2030 Becker Drive, Lawrence, Kansas 66047, USA
| | - Alex Ondracek
- Molecular, Cellular and Developmental Biology Program, Division of Biology, Kansas State University, 338 Ackert Hall, Manhattan, Kansas 66506, USA
| | - Eric J Deeds
- 1] Center for Computational Biology, University of Kansas, 2030 Becker Drive, Lawrence, Kansas 66047, USA [2] Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66047, USA [3] Santa Fe Institute, Santa Fe, New Mexico 87501, USA
| | - Jeroen Roelofs
- 1] Graduate Biochemistry Group, Department of Biochemistry and Molecular Biophysics, Kansas State University, 336 Ackert Hall, Manhattan, Kansas 66506, USA [2] Molecular, Cellular and Developmental Biology Program, Division of Biology, Kansas State University, 338 Ackert Hall, Manhattan, Kansas 66506, USA
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Tumor necrosis factor alpha stimulates p62 accumulation and enhances proteasome activity independently of ROS. Cell Biol Toxicol 2015; 31:83-94. [PMID: 25761618 DOI: 10.1007/s10565-015-9295-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Accepted: 02/25/2015] [Indexed: 12/20/2022]
Abstract
Circulating TNF-α levels are elevated in a wide variety of cardiovascular pathologies including congestive heart failure (CHF). This cytokine is one of the leading mediators of the immune inflammatory response with widespread biological functions regulated by membrane receptors. The pathophysiological implication of the downstream effects of activating the TNF-α system in CHF appears to depend on its direct effects on the heart and endothelium. Evidence supporting the notion that circulating TNF-α promotes protein breakdown was initially obtained from studies utilizing transgenic animals overexpressing TNF-α, animals with experimental diseases that augment TNF-α and in animals treated with exogenous TNF-α. It was then demonstrated that TNF-α acts directly on cultured myotubes to stimulate catabolism; however, whether the effects are the same in the heart remains poorly understood. The present study shows that TNF-α treatment induces autophagy, but clearance through this pathway appears obstructed and, consequently, results in increased protein ubiquitination. Furthermore, prolonged TNF-α treatment enhanced E3 ubiquitin ligase expression but reduced activity of the proteasome. These results suggest that TNF-α induces sarcomeric dysfunction and remodeling by disrupting autophagy and elevating the degradation of myofibrillar proteins. Therefore, myocardial remodeling, as a consequence to reduced contractile proteins, contributes to contractile dysfunction, a symptom often observed in the end stages of CHF.
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Priestman MA, Wang Q, Jernigan FE, Chowdhury R, Schmidt M, Lawrence DS. Multicolor monitoring of the proteasome's catalytic signature. ACS Chem Biol 2015; 10:433-40. [PMID: 25347733 PMCID: PMC4340355 DOI: 10.1021/cb5007322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
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The proteasome, a validated anticancer
target, participates in
an array of biochemical activities, which range from the proteolysis
of defective proteins to antigen presentation. We report the preparation
of biochemically and photophysically distinct green, red, and far-red
real-time sensors designed to simultaneously monitor the proteasome’s
chymotrypsin-, trypsin-, and caspase-like activities, respectively.
These sensors were employed to assess the effect of simultaneous multiple
active site catalysis on the kinetic properties of the individual
subunits. Furthermore, we have found that the catalytic signature
of the proteasome varies depending on the source, cell type, and disease
state. Trypsin-like activity is more pronounced in yeast than in mammals,
whereas chymotrypsin-like activity is the only activity detectable
in B-cells (unlike other mammalian cells). Furthermore, chymotrypsin-like
activity is more prominent in transformed B cells relative to their
counterparts from healthy donors.
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Affiliation(s)
- Melanie A. Priestman
- Department
of Chemistry, Division of Chemical Biology and Medicinal Chemistry,
and Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Qunzhao Wang
- Department
of Chemistry, Division of Chemical Biology and Medicinal Chemistry,
and Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Finith E. Jernigan
- Department
of Chemistry, Division of Chemical Biology and Medicinal Chemistry,
and Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Ruma Chowdhury
- Department
of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, United States
| | - Marion Schmidt
- Department
of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, United States
| | - David S. Lawrence
- Department
of Chemistry, Division of Chemical Biology and Medicinal Chemistry,
and Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, United States
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50
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Bisbenzimidazole derivatives as potent inhibitors of the trypsin-like sites of the immunoproteasome core particle. Biochimie 2015; 108:94-100. [DOI: 10.1016/j.biochi.2014.11.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 11/05/2014] [Indexed: 02/05/2023]
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