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Sano A, Inoue J, Kakazu E, Ninomiya M, Tsuruoka M, Sato K, Onuki M, Sawahashi S, Ouchi K, Masamune A. Association of Omega-3 Polyunsaturated Fatty Acids with Sarcopenia in Liver Cirrhosis Patients with Hepatocellular Carcinoma. J Clin Transl Hepatol 2024; 12:613-624. [PMID: 38993515 PMCID: PMC11233978 DOI: 10.14218/jcth.2024.00036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 03/19/2024] [Accepted: 04/12/2024] [Indexed: 07/13/2024] Open
Abstract
Background and Aims Sarcopenia is associated with the prognosis of patients with liver cirrhosis and hepatocellular carcinoma (HCC). Given their diverse physiological activities, we hypothesized that plasma fatty acids might influence the progression of sarcopenia. This study aimed to clarify the association between fatty acids and sarcopenia in cirrhotic patients with HCC. Methods In this single-center retrospective study, we registered 516 cases and analyzed 414 cases of liver cirrhosis and HCC. The skeletal muscle mass index was measured using a transverse computed tomography scan image at the third lumbar vertebra. The cutoff value for sarcopenia followed the criteria set by the Japan Society of Hepatology. Fatty acid concentrations were measured by gas chromatography. Results Fatty acid levels, particularly omega-3 (n-3) polyunsaturated fatty acid (PUFA), were lower in patients with poor liver function (Child-Pugh grade B/C) and were negatively correlated with the albumin-bilirubin score (p<0.0001). The prognosis of HCC patients with low PUFA levels was significantly worse. Among the different fatty acid fractions, only n-3 PUFAs significantly correlated with skeletal muscle mass index (p=0.0026). In the multivariate analysis, the n-3 PUFA level was an independent variable associated with sarcopenia (p=0.0006). Conclusions A low level of n-3 PUFAs was associated with sarcopenia in patients with liver cirrhosis and HCC.
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Affiliation(s)
- Akitoshi Sano
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Jun Inoue
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Eiji Kakazu
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
- Department of Liver Disease, The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Chiba, Japan
| | - Masashi Ninomiya
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Mio Tsuruoka
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Kosuke Sato
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Masazumi Onuki
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Satoko Sawahashi
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Keishi Ouchi
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Atsushi Masamune
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
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2
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Arkinson C, Dong KC, Gee CL, Costello SM, Marqusee S, Martin A. Nub1 traps unfolded FAT10 for ubiquitin-independent degradation by the 26S proteasome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.12.598715. [PMID: 38915702 PMCID: PMC11195292 DOI: 10.1101/2024.06.12.598715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
The ubiquitin-like modifier FAT10 targets hundreds of proteins in the mammalian immune system to the 26S proteasome for degradation. This degradation pathway requires the cofactor Nub1, yet the underlying mechanisms remain unknown. Here, we reconstituted a minimal in vitro system and revealed that Nub1 utilizes FAT10's intrinsic instability to trap its N-terminal ubiquitin-like domain in an unfolded state and deliver it to the 26S proteasome for engagement, allowing the degradation of FAT10-ylated substrates in a ubiquitin- and p97-independent manner. Through hydrogen-deuterium exchange, structural modeling, and site-directed mutagenesis, we identified the formation of a peculiar complex with FAT10 that activates Nub1 for docking to the 26S proteasome, and our cryo-EM studies visualized the highly dynamic Nub1 complex bound to the proteasomal Rpn1 subunit during FAT10 delivery and the early stages of ATP-dependent degradation. These studies thus identified a novel mode of cofactor-mediated, ubiquitin-independent substrate delivery to the 26S proteasome that relies on trapping partially unfolded states for engagement by the proteasomal ATPase motor.
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Affiliation(s)
- Connor Arkinson
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA94720, USA
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA94720, USA
| | - Ken C. Dong
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA94720, USA
| | - Christine L. Gee
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA94720, USA
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA94720, USA
| | - Shawn M. Costello
- Biophysics Graduate Program, University of California, Berkeley, CA, USA
| | - Susan Marqusee
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA94720, USA
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA94720, USA
- Department of Chemistry, University of California, Berkeley, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Andreas Martin
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA94720, USA
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA94720, USA
- Lead contact
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3
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Spano D, Catara G. Targeting the Ubiquitin-Proteasome System and Recent Advances in Cancer Therapy. Cells 2023; 13:29. [PMID: 38201233 PMCID: PMC10778545 DOI: 10.3390/cells13010029] [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: 11/13/2023] [Revised: 12/12/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024] Open
Abstract
Ubiquitination is a reversible post-translational modification based on the chemical addition of ubiquitin to proteins with regulatory effects on various signaling pathways. Ubiquitination can alter the molecular functions of tagged substrates with respect to protein turnover, biological activity, subcellular localization or protein-protein interaction. As a result, a wide variety of cellular processes are under ubiquitination-mediated control, contributing to the maintenance of cellular homeostasis. It follows that the dysregulation of ubiquitination reactions plays a relevant role in the pathogenic states of human diseases such as neurodegenerative diseases, immune-related pathologies and cancer. In recent decades, the enzymes of the ubiquitin-proteasome system (UPS), including E3 ubiquitin ligases and deubiquitinases (DUBs), have attracted attention as novel druggable targets for the development of new anticancer therapeutic approaches. This perspective article summarizes the peculiarities shared by the enzymes involved in the ubiquitination reaction which, when deregulated, can lead to tumorigenesis. Accordingly, an overview of the main pharmacological interventions based on targeting the UPS that are in clinical use or still in clinical trials is provided, also highlighting the limitations of the therapeutic efficacy of these approaches. Therefore, various attempts to circumvent drug resistance and side effects as well as UPS-related emerging technologies in anticancer therapeutics are discussed.
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Affiliation(s)
- Daniela Spano
- Institute for Endocrinology and Experimental Oncology “G. Salvatore”, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Giuliana Catara
- Institute of Biochemistry and Cell Biology, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
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4
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Chen S, Wang Q, Wang H, Xia S. Endoplasmic reticulum stress in T cell-mediated diseases. Scand J Immunol 2023; 98:e13307. [PMID: 38441291 DOI: 10.1111/sji.13307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 05/23/2023] [Accepted: 06/18/2023] [Indexed: 03/07/2024]
Abstract
T cells synthesize a large number of proteins during their development, activation, and differentiation. The build-up of misfolded and unfolded proteins in the endoplasmic reticulum, however, causes endoplasmic reticulum (ER) stress. Thus, T cells can maintain ER homeostasis via endoplasmic reticulum-associated degradation, unfolded protein response, and autophagy. In T cell-mediated diseases, such as rheumatoid arthritis, systemic lupus erythematosus, Sjogren's syndrome, type 1 diabetes and vitiligo, ER stress caused by changes in the internal microenvironment can cause disease progression by affecting T cell homeostasis. This review discusses ER stress in T cell formation, activation, differentiation, and T cell-mediated illnesses, and may offer new perspectives on the involvement of T cells in autoimmune disorders and cancer.
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Affiliation(s)
- Shaodan Chen
- Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Qiulei Wang
- Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Hui Wang
- Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Sheng Xia
- Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, China
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5
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Morgan EL, Toni T, Viswanathan R, Robbins Y, Yang X, Cheng H, Gunti S, Huynh A, Sowers AL, Mitchell JB, Allen CT, Chen Z, Van Waes C. Inhibition of USP14 promotes TNFα-induced cell death in head and neck squamous cell carcinoma (HNSCC). Cell Death Differ 2023; 30:1382-1396. [PMID: 37055579 PMCID: PMC10154301 DOI: 10.1038/s41418-023-01144-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 02/16/2023] [Accepted: 02/21/2023] [Indexed: 04/15/2023] Open
Abstract
TNFα is a key mediator of immune, chemotherapy and radiotherapy-induced cytotoxicity, but several cancers, including head and neck squamous cell carcinomas (HNSCC), display resistance to TNFα due to activation of the canonical NFκB pro-survival pathway. However, direct targeting of this pathway is associated with significant toxicity; thus, it is vital to identify novel mechanism(s) contributing to NFκB activation and TNFα resistance in cancer cells. Here, we demonstrate that the expression of proteasome-associated deubiquitinase USP14 is significantly increased in HNSCC and correlates with worse progression free survival in Human Papillomavirus (HPV)- HNSCC. Inhibition or depletion of USP14 inhibited the proliferation and survival of HNSCC cells. Further, USP14 inhibition reduced both basal and TNFα-inducible NFκB activity, NFκB-dependent gene expression and the nuclear translocation of the NFκB subunit RELA. Mechanistically, USP14 bound to both RELA and IκBα and reduced IκBα K48-ubiquitination leading to the degradation of IκBα, a critical inhibitor of the canonical NFκB pathway. Furthermore, we demonstrated that b-AP15, an inhibitor of USP14 and UCHL5, sensitized HNSCC cells to TNFα-mediated cell death, as well as radiation-induced cell death in vitro. Finally, b-AP15 delayed tumor growth and enhanced survival, both as a monotherapy and in combination with radiation, in HNSCC tumor xenograft models in vivo, which could be significantly attenuated by TNFα depletion. These data offer new insights into the activation of NFκB signaling in HNSCC and demonstrate that small molecule inhibitors targeting the ubiquitin pathway warrant further investigation as a novel therapeutic avenue to sensitize these cancers to TNFα- and radiation-induced cytotoxicity.
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Affiliation(s)
- Ethan L Morgan
- Tumor Biology Section, Head and Neck Surgery Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA.
- School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK.
| | - Tiffany Toni
- Tumor Biology Section, Head and Neck Surgery Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
- NIH Medical Research Scholars Program, Bethesda, MD, USA
| | - Ramya Viswanathan
- Tumor Biology Section, Head and Neck Surgery Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Yvette Robbins
- Translational Tumor Immunology Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Xinping Yang
- Tumor Biology Section, Head and Neck Surgery Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Hui Cheng
- Tumor Biology Section, Head and Neck Surgery Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Sreenivasulu Gunti
- Sinonasal and Skull Base Tumor Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Angel Huynh
- Translational Tumor Immunology Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Anastasia L Sowers
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - James B Mitchell
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Clint T Allen
- Translational Tumor Immunology Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Zhong Chen
- Tumor Biology Section, Head and Neck Surgery Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Carter Van Waes
- Tumor Biology Section, Head and Neck Surgery Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
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6
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A Role for the Proteasome Alpha2 Subunit N-Tail in Substrate Processing. Biomolecules 2023; 13:biom13030480. [PMID: 36979414 PMCID: PMC10046698 DOI: 10.3390/biom13030480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/23/2023] [Accepted: 03/01/2023] [Indexed: 03/08/2023] Open
Abstract
The proteolytic active sites of the 26S proteasome are sequestered within the catalytic chamber of its 20S core particle (CP). Access to this chamber is through a narrow channel defined by the seven outer α subunits. In the resting state, the N-termini of neighboring α subunits form a gate blocking access to the channel. The attachment of the activators or regulatory particles rearranges the blocking α subunit N-termini facilitating the entry of substrates. By truncating or mutating each of the participating α N-termini, we report that whereas only a few N-termini are important for maintaining the closed gate, all seven N-termini participate in the open gate. Specifically, the open state is stabilized by a hydrogen bond between an invariant tyrosine (Y) in each subunit with a conserved aspartate (D) in its counterclockwise neighbor. The lone exception is the α1–α2 pair leaving a gap in the ring circumference. The third residue (X) of this YD(X) motif aligns with the open channel. Phenylalanine at this position in the α2 subunit comes in direct contact with the translocating substrate. Consequently, deletion of the α2 N-terminal tail attenuates proteolysis despite the appearance of an open gate state. In summary, the interlacing N-terminal YD(X) motifs regulate both the gating and translocation of the substrate.
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7
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Ivanov AV, Alecsa MS, Popescu R, Starcea MI, Mocanu AM, Rusu C, Miron IC. Pediatric Acute Lymphoblastic Leukemia Emerging Therapies-From Pathway to Target. Int J Mol Sci 2023; 24:ijms24054661. [PMID: 36902091 PMCID: PMC10003692 DOI: 10.3390/ijms24054661] [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: 02/05/2023] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 03/06/2023] Open
Abstract
Over the past 40 years, the 5-years-overall survival rate of pediatric cancer reached 75-80%, and for acute lymphoblastic leukemia (ALL), exceeded 90%. Leukemia continues to be a major cause of mortality and morbidity for specific patient populations, including infants, adolescents, and patients with high-risk genetic abnormalities. The future of leukemia treatment needs to count better on molecular therapies as well as immune and cellular therapy. Advances in the scientific interface have led naturally to advances in the treatment of childhood cancer. These discoveries have involved the recognition of the importance of chromosomal abnormalities, the amplification of the oncogenes, the aberration of tumor suppressor genes, as well as the dysregulation of cellular signaling and cell cycle control. Lately, novel therapies that have already proven efficient on relapsed/refractory ALL in adults are being evaluated in clinical trials for young patients. Tirosine kinase inhibitors are, by now, part of the standardized treatment of Ph+ALL pediatric patients, and Blinatumomab, with promising results in clinical trials, received both FDA and EMA approval for use in children. Moreover, other targeted therapies such as aurora-kinase inhibitors, MEK-inhibitors, and proteasome-inhibitors are involved in clinical trials that include pediatric patients. This is an overview of the novel leukemia therapies that have been developed starting from the molecular discoveries and those that have been applied in pediatric populations.
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Affiliation(s)
- Anca Viorica Ivanov
- Pediatrics Department, Grigore T. Popa University of Medicine and Pharmacy, 16 Universitatii Street, 700115 Iasi, Romania
| | - Mirabela Smaranda Alecsa
- Pediatrics Department, Grigore T. Popa University of Medicine and Pharmacy, 16 Universitatii Street, 700115 Iasi, Romania
- Correspondence: (M.S.A.); (R.P.)
| | - Roxana Popescu
- Medical Genetics Department, Grigore T. Popa University of Medicine and Pharmacy, 16 Universitatii Street, 700115 Iasi, Romania
- Correspondence: (M.S.A.); (R.P.)
| | - Magdalena Iuliana Starcea
- Pediatrics Department, Grigore T. Popa University of Medicine and Pharmacy, 16 Universitatii Street, 700115 Iasi, Romania
| | - Adriana Maria Mocanu
- Pediatrics Department, Grigore T. Popa University of Medicine and Pharmacy, 16 Universitatii Street, 700115 Iasi, Romania
| | - Cristina Rusu
- Medical Genetics Department, Grigore T. Popa University of Medicine and Pharmacy, 16 Universitatii Street, 700115 Iasi, Romania
| | - Ingrith Crenguta Miron
- Pediatrics Department, Grigore T. Popa University of Medicine and Pharmacy, 16 Universitatii Street, 700115 Iasi, Romania
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8
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The Ubiquitin-26S Proteasome Pathway and Its Role in the Ripening of Fleshy Fruits. Int J Mol Sci 2023; 24:ijms24032750. [PMID: 36769071 PMCID: PMC9917055 DOI: 10.3390/ijms24032750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 02/04/2023] Open
Abstract
The 26S proteasome is an ATP-dependent proteolytic complex in eukaryotes, which is mainly responsible for the degradation of damaged and misfolded proteins and some regulatory proteins in cells, and it is essential to maintain the balance of protein levels in the cell. The ubiquitin-26S proteasome pathway, which targets a wide range of protein substrates in plants, is an important post-translational regulatory mechanism involved in various stages of plant growth and development and in the maturation process of fleshy fruits. Fleshy fruit ripening is a complex biological process, which is the sum of a series of physiological and biochemical reactions, including the biosynthesis and signal transduction of ripening related hormones, pigment metabolism, fruit texture changes and the formation of nutritional quality. This paper reviews the structure of the 26S proteasome and the mechanism of the ubiquitin-26S proteasome pathway, and it summarizes the function of this pathway in the ripening process of fleshy fruits.
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9
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Yu P, Hua Z. To Kill or to Be Killed: How Does the Battle between the UPS and Autophagy Maintain the Intracellular Homeostasis in Eukaryotes? Int J Mol Sci 2023; 24:ijms24032221. [PMID: 36768543 PMCID: PMC9917186 DOI: 10.3390/ijms24032221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 01/27/2023] Open
Abstract
The ubiquitin-26S proteasome system and autophagy are two major protein degradation machineries encoded in all eukaryotic organisms. While the UPS is responsible for the turnover of short-lived and/or soluble misfolded proteins under normal growth conditions, the autophagy-lysosomal/vacuolar protein degradation machinery is activated under stress conditions to remove long-lived proteins in the forms of aggregates, either soluble or insoluble, in the cytoplasm and damaged organelles. Recent discoveries suggested an integrative function of these two seemly independent systems for maintaining the proteome homeostasis. One such integration is represented by their reciprocal degradation, in which the small 76-amino acid peptide, ubiquitin, plays an important role as the central signaling hub. In this review, we summarized the current knowledge about the activity control of proteasome and autophagosome at their structural organization, biophysical states, and turnover levels from yeast and mammals to plants. Through comprehensive literature studies, we presented puzzling questions that are awaiting to be solved and proposed exciting new research directions that may shed light on the molecular mechanisms underlying the biological function of protein degradation.
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Affiliation(s)
- Peifeng Yu
- Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, USA
- Interdisciplinary Program in Molecular and Cellular Biology, Ohio University, Athens, OH 45701, USA
| | - Zhihua Hua
- Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, USA
- Interdisciplinary Program in Molecular and Cellular Biology, Ohio University, Athens, OH 45701, USA
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10
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Jonsson E, Htet ZM, Bard JA, Dong KC, Martin A. Ubiquitin modulates 26 S proteasome conformational dynamics and promotes substrate degradation. SCIENCE ADVANCES 2022; 8:eadd9520. [PMID: 36563145 PMCID: PMC9788759 DOI: 10.1126/sciadv.add9520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 10/27/2022] [Indexed: 06/17/2023]
Abstract
The 26S proteasome recognizes thousands of appropriate protein substrates in eukaryotic cells through attached ubiquitin chains and uses its adenosine triphosphatase (ATPase) motor for mechanical unfolding and translocation into a proteolytic chamber. Here, we used single-molecule Förster resonance energy transfer measurements to monitor the conformational dynamics of the proteasome, observe individual substrates during their progression toward degradation, and elucidate how these processes are regulated by ubiquitin chains. Rapid transitions between engagement- and processing-competent proteasome conformations control substrate access to the ATPase motor. Ubiquitin chain binding functions as an allosteric regulator to slow these transitions, stabilize the engagement-competent state, and aid substrate capture to accelerate degradation initiation. Upon substrate engagement, the proteasome remains in processing-competent states for translocation and unfolding, except for apparent motor slips when encountering stably folded domains. Our studies revealed how ubiquitin chains allosterically regulate degradation initiation, which ensures substrate selectivity in a crowded cellular environment.
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Affiliation(s)
- Erik Jonsson
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Zaw Min Htet
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA 94720, USA
| | | | - Ken C. Dong
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Andreas Martin
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA 94720, USA
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11
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Pouyo R, Chung K, Delacroix L, Malgrange B. The ubiquitin-proteasome system in normal hearing and deafness. Hear Res 2022; 426:108366. [PMID: 34645583 DOI: 10.1016/j.heares.2021.108366] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 09/03/2021] [Accepted: 09/23/2021] [Indexed: 12/16/2022]
Abstract
Post-translational modifications of proteins are essential for the proper development and function of many tissues and organs, including the inner ear. Ubiquitination is a highly selective post-translational modification that involves the covalent conjugation of ubiquitin to a substrate protein. The most common outcome of protein ubiquitination is degradation by the ubiquitin-proteasome system (UPS), preventing the accumulation of misfolded, damaged, and excess proteins. In addition to proteasomal degradation, ubiquitination regulates other cellular processes, such as transcription, translation, endocytosis, receptor activity, and subcellular localization. All of these processes are essential for cochlear development and maintenance, as several studies link impairment of UPS with altered cochlear development and hearing loss. In this review, we provide insight into the well-oiled machinery of UPS with a focus on its confirmed role in normal hearing and deafness and potential therapeutic strategies to prevent and treat UPS-associated hearing loss.
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Affiliation(s)
- Ronald Pouyo
- GIGA-Stem Cells, Developmental Neurobiology Unit, University of Liege, Avenue hippocrate 15, B36 1st Floor B, Liege 4000, Belgium
| | - Keshi Chung
- GIGA-Stem Cells, Developmental Neurobiology Unit, University of Liege, Avenue hippocrate 15, B36 1st Floor B, Liege 4000, Belgium
| | - Laurence Delacroix
- GIGA-Stem Cells, Developmental Neurobiology Unit, University of Liege, Avenue hippocrate 15, B36 1st Floor B, Liege 4000, Belgium
| | - Brigitte Malgrange
- GIGA-Stem Cells, Developmental Neurobiology Unit, University of Liege, Avenue hippocrate 15, B36 1st Floor B, Liege 4000, Belgium.
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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: 11] [Impact Index Per Article: 5.5] [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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13
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Singh M, Singh A, Yadav N, Yadav DK. Current perspectives of ubiquitination and SUMOylation in abiotic stress tolerance in plants. FRONTIERS IN PLANT SCIENCE 2022; 13:993194. [PMID: 36212351 PMCID: PMC9533872 DOI: 10.3389/fpls.2022.993194] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/16/2022] [Indexed: 06/16/2023]
Abstract
Post-translational modification (PTM) is a critical and rapid mechanism to regulate all the major cellular processes through the modification of diverse protein substrates. Substrate-specific covalent attachment of ubiquitin and Small Ubiquitin-Like Modifier (SUMO) with the target proteins, known as ubiquitination and SUMOylation, respectively, are crucial PTMs that regulate almost every process in the cell by modulating the stability and fidelity of the proteins. Ubiquitination and SUMOylation play a very significant role to provide tolerance to the plants in adverse environmental conditions by activating/deactivating the pre-existing proteins to a great extent. We reviewed the importance of ubiquitination and SUMOylation in plants, implicating its prospects in various abiotic stress regulations. An exhaustive study of molecular mechanisms of ubiquitination and SUMOylation of plant proteins and their role will contribute to the understanding of physiology underlying mitigation of the abiotic stresses and survival in plants. It will be helpful to strategize the improvement of crops for abiotic stress tolerance.
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Affiliation(s)
- Madhavi Singh
- Plant Molecular Biology and Genetic Engineering Laboratory, Department of Botany, University of Allahabad, Prayagraj, India
| | - Ananya Singh
- Plant Molecular Biology and Genetic Engineering Laboratory, Department of Botany, University of Allahabad, Prayagraj, India
| | - Neelam Yadav
- Department of Botany, University of Allahabad, Prayagraj, India
| | - Dinesh Kumar Yadav
- Plant Molecular Biology and Genetic Engineering Laboratory, Department of Botany, University of Allahabad, Prayagraj, India
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14
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Protein Quality Control in Glioblastoma: A Review of the Current Literature with New Perspectives on Therapeutic Targets. Int J Mol Sci 2022; 23:ijms23179734. [PMID: 36077131 PMCID: PMC9456419 DOI: 10.3390/ijms23179734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/12/2022] [Accepted: 08/24/2022] [Indexed: 11/17/2022] Open
Abstract
Protein quality control allows eukaryotes to maintain proteostasis under the stress of constantly changing conditions. In this review, we discuss the current literature on PQC, highlighting flaws that must exist for malignancy to occur. At the nidus of PQC, the expression of BAG1-6 reflects the cell environment; each isoform directs proteins toward different, parallel branches of the quality control cascade. The sum of these branches creates a net shift toward either homeostasis or apoptosis. With an established role in ALP, Bag3 is necessary for cell survival in stress conditions including those of the cancerous niche (i.e., hypoxia, hypermutation). Evidence suggests that excessive Bag3–HSP70 activity not only sustains, but also propagates cancers. Its role is anti-apoptotic—which allows malignant cells to persist—and intercellular—with the production of infectious ‘oncosomes’ enabling cancer expansion and recurrence. While Bag3 has been identified as a key prognostic indicator in several cancer types, its investigation is limited regarding glioblastoma. The cochaperone HSP70 has been strongly linked with GBM, while ALP inhibitors have been shown to improve GBM susceptibility to chemotherapeutics. Given the highly resilient, frequently recurrent nature of GBM, the targeting of Bag3 is a necessary consideration for the successful and definitive treatment of GBM.
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15
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NADPH and Mitochondrial Quality Control as Targets for a Circadian-Based Fasting and Exercise Therapy for the Treatment of Parkinson's Disease. Cells 2022; 11:cells11152416. [PMID: 35954260 PMCID: PMC9367803 DOI: 10.3390/cells11152416] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/01/2022] [Accepted: 08/01/2022] [Indexed: 02/01/2023] Open
Abstract
Dysfunctional mitochondrial quality control (MQC) is implicated in the pathogenesis of Parkinson's disease (PD). The improper selection of mitochondria for mitophagy increases reactive oxygen species (ROS) levels and lowers ATP levels. The downstream effects include oxidative damage, failure to maintain proteostasis and ion gradients, and decreased NAD+ and NADPH levels, resulting in insufficient energy metabolism and neurotransmitter synthesis. A ketosis-based metabolic therapy that increases the levels of (R)-3-hydroxybutyrate (BHB) may reverse the dysfunctional MQC by partially replacing glucose as an energy source, by stimulating mitophagy, and by decreasing inflammation. Fasting can potentially raise cytoplasmic NADPH levels by increasing the mitochondrial export and cytoplasmic metabolism of ketone body-derived citrate that increases flux through isocitrate dehydrogenase 1 (IDH1). NADPH is an essential cofactor for nitric oxide synthase, and the nitric oxide synthesized can diffuse into the mitochondrial matrix and react with electron transport chain-synthesized superoxide to form peroxynitrite. Excessive superoxide and peroxynitrite production can cause the opening of the mitochondrial permeability transition pore (mPTP) to depolarize the mitochondria and activate PINK1-dependent mitophagy. Both fasting and exercise increase ketogenesis and increase the cellular NAD+/NADH ratio, both of which are beneficial for neuronal metabolism. In addition, both fasting and exercise engage the adaptive cellular stress response signaling pathways that protect neurons against the oxidative and proteotoxic stress implicated in PD. Here, we discuss how intermittent fasting from the evening meal through to the next-day lunch together with morning exercise, when circadian NAD+/NADH is most oxidized, circadian NADP+/NADPH is most reduced, and circadian mitophagy gene expression is high, may slow the progression of PD.
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16
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Marshall RS, Vierstra RD. A trio of ubiquitin ligases sequentially drives ubiquitylation and autophagic degradation of dysfunctional yeast proteasomes. Cell Rep 2022; 38:110535. [PMID: 35294869 DOI: 10.1016/j.celrep.2022.110535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 12/08/2021] [Accepted: 02/25/2022] [Indexed: 12/22/2022] Open
Abstract
As central effectors of ubiquitin (Ub)-mediated proteolysis, proteasomes are regulated at multiple levels, including degradation of unwanted or dysfunctional particles via autophagy (termed proteaphagy). In yeast, inactive proteasomes are exported from the nucleus, sequestered into cytoplasmic aggresomes via the Hsp42 chaperone, extensively ubiquitylated, and then tethered to the expanding phagophore by the autophagy receptor Cue5. Here, we demonstrate the need for ubiquitylation driven by the trio of Ub ligases (E3s), San1, Rsp5, and Hul5, which together with their corresponding E2s work sequentially to promote nuclear export and Cue5 recognition. Whereas San1 functions prior to nuclear export, Rsp5 and Hul5 likely decorate aggresome-localized proteasomes in concert. Ultimately, topologically complex Ub chain(s) containing both K48 and K63 Ub-Ub linkages are assembled, mainly on the regulatory particle, to generate autophagy-competent substrates. Because San1, Rsp5, Hul5, Hsp42, and Cue5 also participate in general proteostasis, proteaphagy likely engages a fundamental mechanism for eliminating inactive/misfolded proteins.
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Affiliation(s)
- Richard S Marshall
- Department of Biology, Washington University in St. Louis, 1 Brookings Drive, St. Louis, Missouri 63130, USA.
| | - Richard D Vierstra
- Department of Biology, Washington University in St. Louis, 1 Brookings Drive, St. Louis, Missouri 63130, USA.
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17
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Mammalian Ddi2 is a shuttling factor containing a retroviral protease domain that influences binding of ubiquitylated proteins and proteasomal degradation. J Biol Chem 2022; 298:101875. [PMID: 35358511 PMCID: PMC9062259 DOI: 10.1016/j.jbc.2022.101875] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 03/10/2022] [Accepted: 03/11/2022] [Indexed: 11/24/2022] Open
Abstract
Although several proteasome subunits have been shown to bind ubiquitin (Ub) chains, many ubiquitylated substrates also associate with 26S proteasomes via “shuttling factors.” Unlike the well-studied yeast shuttling factors Rad23 and Dsk2, vertebrate homologs Ddi2 and Ddi1 lack a Ub-associated domain; therefore, it is unclear how they bind Ub. Here, we show that deletion of Ddi2 leads to the accumulation of Ub conjugates with K11/K48 branched chains. We found using affinity copurifications that Ddi2 binds Ub conjugates through its Ub-like domain, which is also required for Ddi2 binding to proteasomes. Furthermore, in cell extracts, adding Ub conjugates increased the amount of Ddi2 associated with proteasomes, and adding Ddi2 increased the binding of Ub conjugates to purified proteasomes. In addition, Ddi2 also contains a retroviral protease domain with undefined cellular roles. We show that blocking the endoprotease activity of Ddi2 either genetically or with the HIV protease inhibitor nelfinavir increased its binding to Ub conjugates but decreased its binding to proteasomes and reduced subsequent protein degradation by proteasomes leading to further accumulation of Ub conjugates. Finally, nelfinavir treatment required Ddi2 to induce the unfolded protein response. Thus, Ddi2 appears to function as a shuttling factor in endoplasmic reticulum–associated protein degradation and delivers K11/K48-ubiquitylated proteins to the proteasome. We conclude that the protease activity of Ddi2 influences this shuttling factor activity, promotes protein turnover, and helps prevent endoplasmic reticulum stress, which may explain nelfinavir’s ability to enhance cell killing by proteasome inhibitors.
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18
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Perisetti A, Goyal H, Yendala R, Chandan S, Tharian B, Thandassery RB. Sarcopenia in hepatocellular carcinoma: Current knowledge and future directions. World J Gastroenterol 2022; 28:432-448. [PMID: 35125828 PMCID: PMC8790553 DOI: 10.3748/wjg.v28.i4.432] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/29/2021] [Accepted: 01/11/2022] [Indexed: 02/06/2023] Open
Abstract
Liver cancer is the second most occurring cancer worldwide and is one of the leading causes of cancer-related deaths. Hepatocellular carcinoma (HCC) is the most common (80%-90%) type among malignant liver cancers. Sarcopenia occurs very early in HCC and can predict and provide an opportunity to improve muscle health before engaging in the treatment options such as loco-regional, systemic, and transplant management. Multiple prognostic stating systems have been developed in HCC, such as Barcelona Clinic Liver Cancer, Child-Pugh score and Albumin-Bilirubin grade. However, the evaluation of patients' performance status is a major limitation of these scoring systems. In this review, we aim to summarize the current knowledge and recent advances about the role of sarcopenia in cirrhosis in general, while focusing specifically on HCC. Additionally, the role of sarcopenia in predicting clinical outcomes and prognostication in HCC patients undergoing loco-regional therapies, liver resection, liver transplantation and systematic therapy has been discussed. A literature review was performed using databases PubMed/MEDLINE, EMBASE, Cochrane, Web of Science, and CINAHL on April 1, 2021, to identify published reports on sarcopenia in HCC. Sarcopenia can independently predict HCC-related mortality especially in patients undergoing treatments such as loco-regional, surgical liver transplantation and systemic therapies. Basic research is focused on evaluating a balance of anabolic and catabolic pathways responsible for muscle health. Early clinical studies have shown promising results in methods to improve sarcopenia in HCC which can potentially increase prognosis in these patients. As sarcopenia occurs very early in HCC, it can predict and provide an opportunity to improve muscle health before engaging in the treatment options such as loco-regional, systemic, and transplant management. Further, sarcopenia measurement can obviate the confounding caused by the abdominal ascites in these patients. The use of sarcopenia can add to the existing scoring systems to better prognosticate the HCC.
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Affiliation(s)
- Abhilash Perisetti
- Department of Internal Medicine, Gastroenterology and Hepatology Division, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States
- Department of Interventional Oncology and Surgical Endoscopy, Parkview Health, Fort Wayne, IN 46825, United States
| | - Hemant Goyal
- Department of Internal Medicine, The Wright Center for Graduate Medical Education, The Wright Center for Graduate Medical Education, Scranton, PA 18501, United States
| | - Rachana Yendala
- Department of Hematology and Oncology, Conway Regional Medical Center, Conway, AR 72034, United States
| | - Saurabh Chandan
- Department of Internal Medicine, Gastroenterology and Hepatology Division, CHI Creighton University Medical Center, Omaha, NE 68107, United States
| | - Benjamin Tharian
- Department of Internal Medicine, Gastroenterology and Hepatology Division, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States
| | - Ragesh Babu Thandassery
- Department of Medicine, Central Arkansas Veterans Healthcare System, Little Rock, AR 72205, United States
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19
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Adeshakin FO, Adeshakin AO, Liu Z, Cheng J, Zhang P, Yan D, Zhang G, Wan X. Targeting Oxidative Phosphorylation-Proteasome Activity in Extracellular Detached Cells Promotes Anoikis and Inhibits Metastasis. Life (Basel) 2021; 12:life12010042. [PMID: 35054435 PMCID: PMC8779336 DOI: 10.3390/life12010042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 12/30/2022] Open
Abstract
Metastasis arises owing to tumor cells’ capacity to evade pro-apoptotic signals. Anoikis—the apoptosis of detached cells (from the extracellular matrix (ECM)) is often circumvented by metastatic cells as a result of biochemical and molecular transformations. These facilitate cells’ ability to survive, invade and reattach to secondary sites. Here, we identified deregulated glucose metabolism, oxidative phosphorylation, and proteasome in anchorage-independent cells compared to adherent cells. Metformin an anti-diabetic drug that reduces blood glucose (also known to inhibit mitochondrial Complex I), and proteasome inhibitors were employed to target these changes. Metformin or proteasome inhibitors alone increased misfolded protein accumulation, sensitized tumor cells to anoikis, and impaired pulmonary metastasis in the B16F10 melanoma model. Mechanistically, metformin reduced cellular ATP production, activated AMPK to foster pro-apoptotic unfolded protein response (UPR) through enhanced expression of CHOP in ECM detached cells. Furthermore, AMPK inhibition reduced misfolded protein accumulation, thus highlight relevance of AMPK activation in facilitating metformin-induced stress and UPR cell death. Our findings provide insights into the molecular biology of anoikis resistance and identified metformin and proteasome inhibitors as potential therapeutic options for tumor metastasis.
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Affiliation(s)
- Funmilayo O. Adeshakin
- Guangdong Immune Cell Therapy Engineering and Technology Research Center, Center for Protein and Cell-Based Drugs, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; (F.O.A.); (A.O.A.); (Z.L.); (J.C.); (P.Z.); (D.Y.)
- University of Chinese Academy of Sciences, Beijing 100864, China
| | - Adeleye O. Adeshakin
- Guangdong Immune Cell Therapy Engineering and Technology Research Center, Center for Protein and Cell-Based Drugs, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; (F.O.A.); (A.O.A.); (Z.L.); (J.C.); (P.Z.); (D.Y.)
- University of Chinese Academy of Sciences, Beijing 100864, China
| | - Zhao Liu
- Guangdong Immune Cell Therapy Engineering and Technology Research Center, Center for Protein and Cell-Based Drugs, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; (F.O.A.); (A.O.A.); (Z.L.); (J.C.); (P.Z.); (D.Y.)
| | - Jian Cheng
- Guangdong Immune Cell Therapy Engineering and Technology Research Center, Center for Protein and Cell-Based Drugs, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; (F.O.A.); (A.O.A.); (Z.L.); (J.C.); (P.Z.); (D.Y.)
| | - Pengchao Zhang
- Guangdong Immune Cell Therapy Engineering and Technology Research Center, Center for Protein and Cell-Based Drugs, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; (F.O.A.); (A.O.A.); (Z.L.); (J.C.); (P.Z.); (D.Y.)
- University of Chinese Academy of Sciences, Beijing 100864, China
| | - Dehong Yan
- Guangdong Immune Cell Therapy Engineering and Technology Research Center, Center for Protein and Cell-Based Drugs, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; (F.O.A.); (A.O.A.); (Z.L.); (J.C.); (P.Z.); (D.Y.)
- University of Chinese Academy of Sciences, Beijing 100864, China
| | - Guizhong Zhang
- Guangdong Immune Cell Therapy Engineering and Technology Research Center, Center for Protein and Cell-Based Drugs, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; (F.O.A.); (A.O.A.); (Z.L.); (J.C.); (P.Z.); (D.Y.)
- Correspondence: (G.Z.); (X.W.)
| | - Xiaochun Wan
- Guangdong Immune Cell Therapy Engineering and Technology Research Center, Center for Protein and Cell-Based Drugs, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; (F.O.A.); (A.O.A.); (Z.L.); (J.C.); (P.Z.); (D.Y.)
- University of Chinese Academy of Sciences, Beijing 100864, China
- Correspondence: (G.Z.); (X.W.)
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20
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Loh D, Reiter RJ. Melatonin: Regulation of Biomolecular Condensates in Neurodegenerative Disorders. Antioxidants (Basel) 2021; 10:1483. [PMID: 34573116 PMCID: PMC8465482 DOI: 10.3390/antiox10091483] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/10/2021] [Accepted: 09/13/2021] [Indexed: 12/12/2022] Open
Abstract
Biomolecular condensates are membraneless organelles (MLOs) that form dynamic, chemically distinct subcellular compartments organizing macromolecules such as proteins, RNA, and DNA in unicellular prokaryotic bacteria and complex eukaryotic cells. Separated from surrounding environments, MLOs in the nucleoplasm, cytoplasm, and mitochondria assemble by liquid-liquid phase separation (LLPS) into transient, non-static, liquid-like droplets that regulate essential molecular functions. LLPS is primarily controlled by post-translational modifications (PTMs) that fine-tune the balance between attractive and repulsive charge states and/or binding motifs of proteins. Aberrant phase separation due to dysregulated membrane lipid rafts and/or PTMs, as well as the absence of adequate hydrotropic small molecules such as ATP, or the presence of specific RNA proteins can cause pathological protein aggregation in neurodegenerative disorders. Melatonin may exert a dominant influence over phase separation in biomolecular condensates by optimizing membrane and MLO interdependent reactions through stabilizing lipid raft domains, reducing line tension, and maintaining negative membrane curvature and fluidity. As a potent antioxidant, melatonin protects cardiolipin and other membrane lipids from peroxidation cascades, supporting protein trafficking, signaling, ion channel activities, and ATPase functionality during condensate coacervation or dissolution. Melatonin may even control condensate LLPS through PTM and balance mRNA- and RNA-binding protein composition by regulating N6-methyladenosine (m6A) modifications. There is currently a lack of pharmaceuticals targeting neurodegenerative disorders via the regulation of phase separation. The potential of melatonin in the modulation of biomolecular condensate in the attenuation of aberrant condensate aggregation in neurodegenerative disorders is discussed in this review.
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Affiliation(s)
- Doris Loh
- Independent Researcher, Marble Falls, TX 78654, USA
| | - Russel J. Reiter
- Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, TX 78229, USA
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21
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Reboud-Ravaux M. [The proteasome - structural aspects and inhibitors: a second life for a validated drug target]. Biol Aujourdhui 2021; 215:1-23. [PMID: 34397372 DOI: 10.1051/jbio/2021005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Indexed: 02/06/2023]
Abstract
The proteasome is the central component of the adaptable ubiquitin proteasome system (UPS) discovered in the 1980's. It sustains protein homeostasis (proteostasis) under a large variety of physiological and pathological conditions. Its dysregulation has been often associated to various human diseases. Its potential regulation by modulators has emerged as promising avenue to develop treatments of various pathologies. The FDA approval in 2003 of the proteasome inhibitor bortezomib to treat multiple myeloma, then mantle lymphoma in 2006, has considerably increased the clinical interest of proteasome inhibition. Second-generation proteasome inhibitors (carfilzomib and ixazomib) have been approved to overcome bortezomib resistance and improved toxicity profile and route of administration. Selective inhibition of immunoproteasome is a promising approach towards the development of immunomodulatory drugs. The design of these drugs relies greatly on the elucidation of high-resolution structures of the targeted proteasomes. The ATPase-dependent 26S proteasome (2.4 MDa) consists of a 20S proteolytic core and one or two 19S regulatory particles. The 20S core contains three types of catalytic sites. In recent years, due to technical advances especially in atomic cryo-electron microscopy, significant progress has been made in the understanding of 26S proteasome structure and its dynamics. Stepwise conformational changes of the 19S particle induced by ATP hydrolysis lead to substrate translocation, 20S pore opening and processive protein degradation by the 20S proteolytic subunits (2β1, 2β2 and 2β5). A large variety of structurally different inhibitors, both natural products or synthetic compounds targeting immuno- and constitutive proteasomes, has been discovered. The latest advances in this drug discovery are presented. Knowledge about structures, inhibition mechanism and detailed biological regulations of proteasomes can guide strategies for the development of next-generation inhibitors to treat human diseases, especially cancers, immune disorders and pathogen infections. Proteasome activators are also potentially applicable to the reduction of proteotoxic stresses in neurodegeneration and aging.
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Affiliation(s)
- Michèle Reboud-Ravaux
- Sorbonne Université, Institut de Biologie Paris Seine (IBPS), CNRS UMR 8256, Inserm ERL U1164, 7 quai Saint Bernard, 75252 Paris Cedex 05, France
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22
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Mechanisms That Activate 26S Proteasomes and Enhance Protein Degradation. Biomolecules 2021; 11:biom11060779. [PMID: 34067263 PMCID: PMC8224753 DOI: 10.3390/biom11060779] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 02/07/2023] Open
Abstract
Although ubiquitination is widely assumed to be the only regulated step in the ubiquitin–proteasome pathway, recent studies have demonstrated several important mechanisms that regulate the activities of the 26S proteasome. Most proteasomes in cells are inactive but, upon binding a ubiquitinated substrate, become activated by a two-step mechanism requiring an association of the ubiquitin chain with Usp14 and then a loosely folded protein domain with the ATPases. The initial activation step is signaled by Usp14’s UBL domain, and many UBL-domain-containing proteins (e.g., Rad23, Parkin) also activate the proteasome. ZFAND5 is a distinct type of activator that binds ubiquitin conjugates and the proteasome and stimulates proteolysis during muscle atrophy. The proteasome’s activities are also regulated through subunit phosphorylation. Agents that raise cAMP and activate PKA stimulate within minutes Rpn6 phosphorylation and enhance the selective degradation of short-lived proteins. Likewise, hormones, fasting, and exercise, which raise cAMP, activate proteasomes and proteolysis in target tissues. Agents that raise cGMP and activate PKG also stimulate 26S activities but modify different subunit(s) and stimulate also the degradation of long-lived cell proteins. Both kinases enhance the selective degradation of aggregation-prone proteins that cause neurodegenerative diseases. These new mechanisms regulating proteolysis thus have clear physiological importance and therapeutic potential.
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23
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Mechanistic basis for ubiquitin modulation of a protein energy landscape. Proc Natl Acad Sci U S A 2021; 118:2025126118. [PMID: 33723075 DOI: 10.1073/pnas.2025126118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ubiquitin is a common posttranslational modification canonically associated with targeting proteins to the 26S proteasome for degradation and also plays a role in numerous other nondegradative cellular processes. Ubiquitination at certain sites destabilizes the substrate protein, with consequences for proteasomal processing, while ubiquitination at other sites has little energetic effect. How this site specificity-and, by extension, the myriad effects of ubiquitination on substrate proteins-arises remains unknown. Here, we systematically characterize the atomic-level effects of ubiquitination at various sites on a model protein, barstar, using a combination of NMR, hydrogen-deuterium exchange mass spectrometry, and molecular dynamics simulation. We find that, regardless of the site of modification, ubiquitination does not induce large structural rearrangements in the substrate. Destabilizing modifications, however, increase fluctuations from the native state resulting in exposure of the substrate's C terminus. Both of the sites occur in regions of barstar with relatively high conformational flexibility. Nevertheless, destabilization appears to occur through different thermodynamic mechanisms, involving a reduction in entropy in one case and a loss in enthalpy in another. By contrast, ubiquitination at a nondestabilizing site protects the substrate C terminus through intermittent formation of a structural motif with the last three residues of ubiquitin. Thus, the biophysical effects of ubiquitination at a given site depend greatly on local context. Taken together, our results reveal how a single posttranslational modification can generate a broad array of distinct effects, providing a framework to guide the design of proteins and therapeutics with desired degradation and quality control properties.
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24
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Radzinski M, Oppenheim T, Metanis N, Reichmann D. The Cys Sense: Thiol Redox Switches Mediate Life Cycles of Cellular Proteins. Biomolecules 2021; 11:469. [PMID: 33809923 PMCID: PMC8004198 DOI: 10.3390/biom11030469] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 12/14/2022] Open
Abstract
Protein homeostasis is an essential component of proper cellular function; however, sustaining protein health is a challenging task, especially during the aerobic lifestyle. Natural cellular oxidants may be involved in cell signaling and antibacterial defense; however, imbalanced levels can lead to protein misfolding, cell damage, and death. This merges together the processes of protein homeostasis and redox regulation. At the heart of this process are redox-regulated proteins or thiol-based switches, which carefully mediate various steps of protein homeostasis across folding, localization, quality control, and degradation pathways. In this review, we discuss the "redox code" of the proteostasis network, which shapes protein health during cell growth and aging. We describe the sources and types of thiol modifications and elaborate on diverse strategies of evolving antioxidant proteins in proteostasis networks during oxidative stress conditions. We also highlight the involvement of cysteines in protein degradation across varying levels, showcasing the importance of cysteine thiols in proteostasis at large. The individual examples and mechanisms raised open the door for extensive future research exploring the interplay between the redox and protein homeostasis systems. Understanding this interplay will enable us to re-write the redox code of cells and use it for biotechnological and therapeutic purposes.
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Affiliation(s)
- Meytal Radzinski
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; (M.R.); (T.O.)
| | - Tal Oppenheim
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; (M.R.); (T.O.)
| | - Norman Metanis
- Institute of Chemistry, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
| | - Dana Reichmann
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; (M.R.); (T.O.)
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25
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Zeng J, Santos AF, Mukadam AS, Osswald M, Jacques DA, Dickson CF, McLaughlin SH, Johnson CM, Kiss L, Luptak J, Renner N, Vaysburd M, McEwan WA, Morais-de-Sá E, Clift D, James LC. Target-induced clustering activates Trim-Away of pathogens and proteins. Nat Struct Mol Biol 2021; 28:278-289. [PMID: 33633400 PMCID: PMC7611929 DOI: 10.1038/s41594-021-00560-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 01/13/2021] [Indexed: 01/31/2023]
Abstract
Trim-Away is a recently developed technology that exploits off-the-shelf antibodies and the RING E3 ligase and cytosolic antibody receptor TRIM21 to carry out rapid protein depletion. How TRIM21 is catalytically activated upon target engagement, either during its normal immune function or when repurposed for targeted protein degradation, is unknown. Here we show that a mechanism of target-induced clustering triggers intermolecular dimerization of the RING domain to switch on the ubiquitination activity of TRIM21 and induce virus neutralization or drive Trim-Away. We harness this mechanism for selective degradation of disease-causing huntingtin protein containing long polyglutamine tracts and expand the Trim-Away toolbox with highly active TRIM21-nanobody chimeras that can also be controlled optogenetically. This work provides a mechanism for cellular activation of TRIM RING ligases and has implications for targeted protein degradation technologies.
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Affiliation(s)
- Jingwei Zeng
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, UK
| | - Ana Filipa Santos
- i3S - Instituto de Investigação e Inovação em Saúde and IBMC Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Aamir S. Mukadam
- UK Dementia Research Institute, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Mariana Osswald
- i3S - Instituto de Investigação e Inovação em Saúde and IBMC Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - David A. Jacques
- EMBL Australia Node, Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Claire F. Dickson
- EMBL Australia Node, Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | | | | | - Leo Kiss
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, UK
| | - Jakub Luptak
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, UK
| | - Nadine Renner
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, UK
| | - Marina Vaysburd
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, UK
| | - William A. McEwan
- UK Dementia Research Institute, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK,Correspondence: William McEwan (); Eurico Morais-de-Sá (); Dean Clift (); Leo C. James ()
| | - Eurico Morais-de-Sá
- i3S - Instituto de Investigação e Inovação em Saúde and IBMC Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal,Correspondence: William McEwan (); Eurico Morais-de-Sá (); Dean Clift (); Leo C. James ()
| | - Dean Clift
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, UK,Correspondence: William McEwan (); Eurico Morais-de-Sá (); Dean Clift (); Leo C. James ()
| | - Leo C. James
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, UK,Correspondence: William McEwan (); Eurico Morais-de-Sá (); Dean Clift (); Leo C. James ()
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26
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Sokolova I. Bioenergetics in environmental adaptation and stress tolerance of aquatic ectotherms: linking physiology and ecology in a multi-stressor landscape. J Exp Biol 2021; 224:224/Suppl_1/jeb236802. [PMID: 33627464 DOI: 10.1242/jeb.236802] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Energy metabolism (encompassing energy assimilation, conversion and utilization) plays a central role in all life processes and serves as a link between the organismal physiology, behavior and ecology. Metabolic rates define the physiological and life-history performance of an organism, have direct implications for Darwinian fitness, and affect ecologically relevant traits such as the trophic relationships, productivity and ecosystem engineering functions. Natural environmental variability and anthropogenic changes expose aquatic ectotherms to multiple stressors that can strongly affect their energy metabolism and thereby modify the energy fluxes within an organism and in the ecosystem. This Review focuses on the role of bioenergetic disturbances and metabolic adjustments in responses to multiple stressors (especially the general cellular stress response), provides examples of the effects of multiple stressors on energy intake, assimilation, conversion and expenditure, and discusses the conceptual and quantitative approaches to identify and mechanistically explain the energy trade-offs in multiple stressor scenarios, and link the cellular and organismal bioenergetics with fitness, productivity and/or ecological functions of aquatic ectotherms.
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Affiliation(s)
- Inna Sokolova
- Marine Biology Department, Institute of Biological Sciences, University of Rostock, 18059 Rostock, Germany .,Department of Maritime Systems, Interdisciplinary Faculty, University of Rostock, 18059 Rostock, Germany
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27
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Abstract
The 26S proteasome is the most complex ATP-dependent protease machinery, of ~2.5 MDa mass, ubiquitously found in all eukaryotes. It selectively degrades ubiquitin-conjugated proteins and plays fundamentally indispensable roles in regulating almost all major aspects of cellular activities. To serve as the sole terminal "processor" for myriad ubiquitylation pathways, the proteasome evolved exceptional adaptability in dynamically organizing a large network of proteins, including ubiquitin receptors, shuttle factors, deubiquitinases, AAA-ATPase unfoldases, and ubiquitin ligases, to enable substrate selectivity and processing efficiency and to achieve regulation precision of a vast diversity of substrates. The inner working of the 26S proteasome is among the most sophisticated, enigmatic mechanisms of enzyme machinery in eukaryotic cells. Recent breakthroughs in three-dimensional atomic-level visualization of the 26S proteasome dynamics during polyubiquitylated substrate degradation elucidated an extensively detailed picture of its functional mechanisms, owing to progressive methodological advances associated with cryogenic electron microscopy (cryo-EM). Multiple sites of ubiquitin binding in the proteasome revealed a canonical mode of ubiquitin-dependent substrate engagement. The proteasome conformation in the act of substrate deubiquitylation provided insights into how the deubiquitylating activity of RPN11 is enhanced in the holoenzyme and is coupled to substrate translocation. Intriguingly, three principal modes of coordinated ATP hydrolysis in the heterohexameric AAA-ATPase motor were discovered to regulate intermediate functional steps of the proteasome, including ubiquitin-substrate engagement, deubiquitylation, initiation of substrate translocation and processive substrate degradation. The atomic dissection of the innermost working of the 26S proteasome opens up a new era in our understanding of the ubiquitin-proteasome system and has far-reaching implications in health and disease.
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Affiliation(s)
- Youdong Mao
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, 02215, Massachusetts, USA. .,School of Physics, Center for Quantitative Biology, Peking University, Beijing, 100871, China.
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28
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Lemmer IL, Willemsen N, Hilal N, Bartelt A. A guide to understanding endoplasmic reticulum stress in metabolic disorders. Mol Metab 2021; 47:101169. [PMID: 33484951 PMCID: PMC7887651 DOI: 10.1016/j.molmet.2021.101169] [Citation(s) in RCA: 136] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/08/2021] [Accepted: 01/18/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The global rise of metabolic disorders, such as obesity, type 2 diabetes, and cardiovascular disease, demands a thorough molecular understanding of the cellular mechanisms that govern health or disease. The endoplasmic reticulum (ER) is a key organelle for cellular function and metabolic adaptation and, therefore disturbed ER function, known as "ER stress," is a key feature of metabolic disorders. SCOPE OF REVIEW As ER stress remains a poorly defined phenomenon, this review provides a general guide to understanding the nature, etiology, and consequences of ER stress in metabolic disorders. We define ER stress by its type of stressor, which is driven by proteotoxicity, lipotoxicity, and/or glucotoxicity. We discuss the implications of ER stress in metabolic disorders by reviewing evidence implicating ER phenotypes and organelle communication, protein quality control, calcium homeostasis, lipid and carbohydrate metabolism, and inflammation as key mechanisms in the development of ER stress and metabolic dysfunction. MAJOR CONCLUSIONS In mammalian biology, ER is a phenotypically and functionally diverse platform for nutrient sensing, which is critical for cell type-specific metabolic control by hepatocytes, adipocytes, muscle cells, and neurons. In these cells, ER stress is a distinct, transient state of functional imbalance, which is usually resolved by the activation of adaptive programs such as the unfolded protein response (UPR), ER-associated protein degradation (ERAD), or autophagy. However, challenges to proteostasis also impact lipid and glucose metabolism and vice versa. In the ER, sensing and adaptive measures are integrated and failure of the ER to adapt leads to aberrant metabolism, organelle dysfunction, insulin resistance, and inflammation. In conclusion, the ER is intricately linked to a wide spectrum of cellular functions and is a critical component in maintaining and restoring metabolic health.
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Affiliation(s)
- Imke L Lemmer
- Institute for Cardiovascular Prevention (IPEK), Pettenkoferstr. 9, Ludwig-Maximilians-University, 80336 Munich, Germany; Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Nienke Willemsen
- Institute for Cardiovascular Prevention (IPEK), Pettenkoferstr. 9, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Nazia Hilal
- Institute for Cardiovascular Prevention (IPEK), Pettenkoferstr. 9, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Alexander Bartelt
- Institute for Cardiovascular Prevention (IPEK), Pettenkoferstr. 9, Ludwig-Maximilians-University, 80336 Munich, Germany; Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Technische Universität München, Biedersteiner Str. 29, 80802 München, Germany; Department of Molecular Metabolism, 665 Huntington Avenue, Harvard T.H. Chan School of Public Health, 02115 Boston, MA, USA.
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29
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Sedley L. Advances in Nutritional Epigenetics-A Fresh Perspective for an Old Idea. Lessons Learned, Limitations, and Future Directions. Epigenet Insights 2020; 13:2516865720981924. [PMID: 33415317 PMCID: PMC7750768 DOI: 10.1177/2516865720981924] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 11/25/2020] [Indexed: 12/11/2022] Open
Abstract
Nutritional epigenetics is a rapidly expanding field of research, and the natural modulation of the genome is a non-invasive, sustainable, and personalized alternative to gene-editing for chronic disease management. Genetic differences and epigenetic inflexibility resulting in abnormal gene expression, differential or aberrant methylation patterns account for the vast majority of diseases. The expanding understanding of biological evolution and the environmental influence on epigenetics and natural selection requires relearning of once thought to be well-understood concepts. This research explores the potential for natural modulation by the less understood epigenetic modifications such as ubiquitination, nitrosylation, glycosylation, phosphorylation, and serotonylation concluding that the under-appreciated acetylation and mitochondrial dependant downstream epigenetic post-translational modifications may be the pinnacle of the epigenomic hierarchy, essential for optimal health, including sustainable cellular energy production. With an emphasis on lessons learned, this conceptional exploration provides a fresh perspective on methylation, demonstrating how increases in environmental methane drive an evolutionary down regulation of endogenous methyl groups synthesis and demonstrates how epigenetic mechanisms are cell-specific, making supplementation with methyl cofactors throughout differentiation unpredictable. Interference with the epigenomic hierarchy may result in epigenetic inflexibility, symptom relief and disease concomitantly and may be responsible for the increased incidence of neurological disease such as autism spectrum disorder.
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Affiliation(s)
- Lynda Sedley
- Bachelor of Health Science (Nutritional Medicine),
GC Biomedical Science (Genomics), The Research and Educational Institute of
Environmental and Nutritional Epigenetics, Queensland, Australia
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30
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Reeg S, Castro JP, Hugo M, Grune T. Accumulation of polyubiquitinated proteins: A consequence of early inactivation of the 26S proteasome. Free Radic Biol Med 2020; 160:293-302. [PMID: 32822745 DOI: 10.1016/j.freeradbiomed.2020.08.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 08/10/2020] [Accepted: 08/11/2020] [Indexed: 11/18/2022]
Abstract
The proteasomal degradation system is one of the most important protein degradation systems in the cytosol and nucleus. This system is present in two major forms: the ATP-stimulated 26S/30 S proteasome or the ATP-independent 20S core proteasome. While the first recognize ubiquitin-tagged target proteins and degrade them, the 20S proteasome works also independent from ATP, but requires partially unfolded substrates. While the role of the proteasome in the selective removal of oxidized proteins is undoubted, the debate about a selective ubiquitination of oxidized proteins is still ongoing. Here we demonstrate, that under some conditions of oxidative stress an accumulation of oxidized and of K48-ubiquitinated proteins occurs. However, the removal of oxidized proteins seems not to be linked to ubiquitination. In further experiments, we could show that the accumulation of ubiquitinated proteins under certain oxidative stress conditions is rather a result of a different sensitivity of the 26S proteasome and the ubiquitination machinery towards oxidants.
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Affiliation(s)
- Sandra Reeg
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbrücke, 14558, Nuthetal, Germany
| | - José P Castro
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbrücke, 14558, Nuthetal, Germany; German Center for Diabetes Research (DZD), 85764, München-Neuherberg, Germany
| | - Martin Hugo
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbrücke, 14558, Nuthetal, Germany
| | - Tilman Grune
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbrücke, 14558, Nuthetal, Germany; German Center for Diabetes Research (DZD), 85764, München-Neuherberg, Germany; German Center for Cardiovascular Research (DZHK), 10117, Berlin, Germany; University of Potsdam, Institute of Nutritional Science, 14558, Nuthetal, Germany.
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31
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Srikanta SB, Cermakian N. To Ub or not to Ub: Regulation of circadian clocks by ubiquitination and deubiquitination. J Neurochem 2020; 157:11-30. [PMID: 32717140 DOI: 10.1111/jnc.15132] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/10/2020] [Accepted: 07/14/2020] [Indexed: 12/28/2022]
Abstract
Circadian clocks are internal timing systems that enable organisms to adjust their behavioral and physiological rhythms to the daily changes of their environment. These clocks generate self-sustained oscillations at the cellular, tissue, and behavioral level. The rhythm-generating mechanism is based on a gene expression network with a delayed negative feedback loop that causes the transcripts to oscillate with a period of approximately 24 hr. This oscillatory nature of the proteins involved in this network necessitates that they are intrinsically unstable, with a short half-life. Hence, post-translational modifications (PTMs) are important to precisely time the presence, absence, and interactions of these proteins at appropriate times of the day. Ubiquitination and deubiquitination are counter-balancing PTMs which play a key role in this regulatory process. In this review, we take a comprehensive look at the roles played by the processes of ubiquitination and deubiquitination in the clock machinery of the most commonly studied eukaryotic models of the circadian clock: plants, fungi, fruit flies, and mammals. We present the effects exerted by ubiquitinating and deubiquitinating enzymes on the stability, but also the activity, localization, and interactions of clock proteins. Overall, these PTMs have key roles in regulating not only the pace of the circadian clocks but also their response to external cues and their control of cellular functions.
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Affiliation(s)
- Shashank Bangalore Srikanta
- Integrated Program in Neuroscience, McGill University, Montréal, QC, Canada.,Laboratory of Molecular Chronobiology, Douglas Research Centre, Montréal, QC, Canada
| | - Nicolas Cermakian
- Laboratory of Molecular Chronobiology, Douglas Research Centre, Montréal, QC, Canada.,Department of Psychiatry, McGill University, Montréal, QC, Canada
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32
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Musaus M, Navabpour S, Jarome TJ. The diversity of linkage-specific polyubiquitin chains and their role in synaptic plasticity and memory formation. Neurobiol Learn Mem 2020; 174:107286. [PMID: 32745599 DOI: 10.1016/j.nlm.2020.107286] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/15/2020] [Accepted: 07/28/2020] [Indexed: 12/12/2022]
Abstract
Over the last 20 years, a number of studies have provided strong support for protein degradation mediated by the ubiquitin-proteasome system in synaptic plasticity and memory formation. In this system, target substrates become covalently modified by the small protein ubiquitin through a series of enzymatic reactions involving hundreds of different ligases. While some substrates will acquire only a single ubiquitin, most will be marked by multiple ubiquitin modifications, which link together at specific lysine sites or the N-terminal methionine on the previous ubiquitin to form a polyubiquitin chain. There are at least eight known linkage-specific polyubiquitin chains a target protein can acquire, many of which are independent of the proteasome, and these chains can be homogenous, mixed, or branched in nature, all of which result in different functional outcomes and fates for the target substrate. However, as the focus has remained on protein degradation, much remains unknown about the role of these diverse ubiquitin chains in the brain, particularly during activity- and learning-dependent synaptic plasticity. Here, we review the different types and functions of ubiquitin chains and summarize evidence suggesting a role for these diverse ubiquitin modifications in synaptic plasticity and memory formation. We conclude by discussing how technological limitations have limited our ability to identify and elucidate the role of different ubiquitin chains in the brain and speculate on the future directions and implications of understanding linkage-specific ubiquitin modifications in activity- and learning-dependent synaptic plasticity.
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Affiliation(s)
- Madeline Musaus
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Shaghayegh Navabpour
- Fralin Biomedical Research Institute, Translational Biology, Medicine and Health, Virginia Polytechnic Institute and State University, Roanoke, VA, USA
| | - Timothy J Jarome
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA; Fralin Biomedical Research Institute, Translational Biology, Medicine and Health, Virginia Polytechnic Institute and State University, Roanoke, VA, USA; Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
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33
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Zhang C, Wei Y, Xu L, Wu KC, Yang L, Shi CN, Yang GY, Chen D, Yu FF, Xie Q, Ding SW, Wu JG. A Bunyavirus-Inducible Ubiquitin Ligase Targets RNA Polymerase IV for Degradation during Viral Pathogenesis in Rice. MOLECULAR PLANT 2020; 13:836-850. [PMID: 32087369 DOI: 10.1016/j.molp.2020.02.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/18/2020] [Accepted: 02/14/2020] [Indexed: 05/19/2023]
Abstract
The ubiquitin-proteasome system (UPS) is an important post-translational regulatory mechanism that controls many cellular functions in eukaryotes. Here, we show that stable expression of P3 protein encoded by Rice grassy stunt virus (RGSV), a negative-strand RNA virus in the Bunyavirales, causes developmental abnormities similar to the disease symptoms caused by RGSV, such as dwarfing and excess tillering, in transgenic rice plants. We found that both transgenic expression of P3 and RGSV infection induce ubiquitination and UPS-dependent degradation of rice NUCLEAR RNA POLYMERASE D1a (OsNRPD1a), one of two orthologs of the largest subunit of plant-specific RNA polymerase IV (Pol IV), which is required for RNA-directed DNA methylation (RdDM). Furthermore, we identified a P3-inducible U-box type E3 ubiquitin ligase, designated as P3-inducible protein 1 (P3IP1), which interacts with OsNRPD1a and mediates its ubiquitination and UPS-dependent degradation in vitro and in vivo. Notably, both knockdown of OsNRPD1 and overexpression of P3IP1 in rice plants induced developmental phenotypes similar to RGSV disease symptomss. Taken together, our findings reveal a novel virulence mechanism whereby plant pathogens target host RNA Pol IV for UPS-dependent degradation to induce disease symptoms. Our study also identified an E3 ubiquitin ligase, which targets the RdDM compotent NRPD1 for UPS-mediated degradation in rice.
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Affiliation(s)
- Chao Zhang
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Ying Wei
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Le Xu
- Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, College of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Kang-Cheng Wu
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Liang Yang
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Chao-Nan Shi
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Guo-Yi Yang
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Dong Chen
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Fei-Fei Yu
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qi Xie
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Shou-Wei Ding
- Department of Microbiology and Plant Pathology and Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA, 92521, USA
| | - Jian-Guo Wu
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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34
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Cheng J, Su Q, Xia J, Yang Z, Shi C, Wang S, Wu Q, Li C, Zhang Y. Comparative transcriptome analysis of differentially expressed genes in Bradysia odoriphaga Yang et Zhang (Diptera: Sciaridae) at different acute stress temperatures. Genomics 2020; 112:3739-3750. [PMID: 32353477 DOI: 10.1016/j.ygeno.2020.04.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 03/19/2020] [Accepted: 04/24/2020] [Indexed: 10/24/2022]
Abstract
The gnat, Bradysia odoriphaga Yang et Zhang, is an important underground pest in Asia. B. odoriphaga differ in heat and cold tolerance and exhibit quite different developmental strategies. To understand the underlying mechanisms, we sequenced and compared the transcriptome of B. odoriphaga under 40 °C (a stressful high temperature), 25 °C, and 4 °C (a stressful low temperature) for 1 h. We found that metabolism- and ribosome-related genes were modulated. In high temperature (40 °C), heat shock protein (HSP) genes, detoxication genes, metabolism genes, protein turnover genes, and stress signal transduction genes were differentially expressed. In low temperature (4 °C), genes related with heat shock protein (HSP) and detoxication were differentially expressed. Our study increases our understanding of the complex molecular mechanisms involved in the responses of B. odoriphaga to acute temperature stress and provides a potential strategy for pest management.
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Affiliation(s)
- Jiaxu Cheng
- Hubei Engineering Technology Center for Pest Forewarning and Management, College of Agriculture, Yangtze University, Jingzhou, Hubei 434025, PR China; Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Qi Su
- Hubei Engineering Technology Center for Pest Forewarning and Management, College of Agriculture, Yangtze University, Jingzhou, Hubei 434025, PR China
| | - Jixing Xia
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Zezhong Yang
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Caihua Shi
- Hubei Engineering Technology Center for Pest Forewarning and Management, College of Agriculture, Yangtze University, Jingzhou, Hubei 434025, PR China
| | - Shaoli Wang
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Qingjun Wu
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Chuanren Li
- Hubei Engineering Technology Center for Pest Forewarning and Management, College of Agriculture, Yangtze University, Jingzhou, Hubei 434025, PR China
| | - Youjun Zhang
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China.
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35
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AAA+ ATPases in Protein Degradation: Structures, Functions and Mechanisms. Biomolecules 2020; 10:biom10040629. [PMID: 32325699 PMCID: PMC7226402 DOI: 10.3390/biom10040629] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/21/2020] [Accepted: 03/30/2020] [Indexed: 12/28/2022] Open
Abstract
Adenosine triphosphatases (ATPases) associated with a variety of cellular activities (AAA+), the hexameric ring-shaped motor complexes located in all ATP-driven proteolytic machines, are involved in many cellular processes. Powered by cycles of ATP binding and hydrolysis, conformational changes in AAA+ ATPases can generate mechanical work that unfolds a substrate protein inside the central axial channel of ATPase ring for degradation. Three-dimensional visualizations of several AAA+ ATPase complexes in the act of substrate processing for protein degradation have been resolved at the atomic level thanks to recent technical advances in cryogenic electron microscopy (cryo-EM). Here, we summarize the resulting advances in structural and biochemical studies of AAA+ proteases in the process of proteolysis reactions, with an emphasis on cryo-EM structural analyses of the 26S proteasome, Cdc48/p97 and FtsH-like mitochondrial proteases. These studies reveal three highly conserved patterns in the structure–function relationship of AAA+ ATPase hexamers that were observed in the human 26S proteasome, thus suggesting common dynamic models of mechanochemical coupling during force generation and substrate translocation.
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36
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Buel GR, Chen X, Chari R, O'Neill MJ, Ebelle DL, Jenkins C, Sridharan V, Tarasov SG, Tarasova NI, Andresson T, Walters KJ. Structure of E3 ligase E6AP with a proteasome-binding site provided by substrate receptor hRpn10. Nat Commun 2020; 11:1291. [PMID: 32157086 PMCID: PMC7064531 DOI: 10.1038/s41467-020-15073-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 02/15/2020] [Indexed: 12/16/2022] Open
Abstract
Regulated proteolysis by proteasomes involves ~800 enzymes for substrate modification with ubiquitin, including ~600 E3 ligases. We report here that E6AP/UBE3A is distinguished from other E3 ligases by having a 12 nM binding site at the proteasome contributed by substrate receptor hRpn10/PSMD4/S5a. Intrinsically disordered by itself, and previously uncharacterized, the E6AP-binding domain in hRpn10 locks into a well-defined helical structure to form an intermolecular 4-helix bundle with the E6AP AZUL, which is unique to this E3. We thus name the hRpn10 AZUL-binding domain RAZUL. We further find in human cells that loss of RAZUL by CRISPR-based gene editing leads to loss of E6AP at proteasomes. Moreover, proteasome-associated ubiquitin is reduced following E6AP knockdown or displacement from proteasomes, suggesting that E6AP ubiquitinates substrates at or for the proteasome. Altogether, our findings indicate E6AP to be a privileged E3 for the proteasome, with a dedicated, high affinity binding site contributed by hRpn10.
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Affiliation(s)
- Gwen R Buel
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Xiang Chen
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Raj Chari
- Genome Modification Core, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Maura J O'Neill
- Protein Characterization Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Danielle L Ebelle
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Conor Jenkins
- Protein Characterization Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Vinidhra Sridharan
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Sergey G Tarasov
- Biophysics Resource, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Nadya I Tarasova
- Laboratory of Cancer Immunometabolism, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Thorkell Andresson
- Protein Characterization Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Kylie J Walters
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
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Proteins containing ubiquitin-like (Ubl) domains not only bind to 26S proteasomes but also induce their activation. Proc Natl Acad Sci U S A 2020; 117:4664-4674. [PMID: 32071216 DOI: 10.1073/pnas.1915534117] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
During protein degradation by the ubiquitin-proteasome pathway, latent 26S proteasomes in the cytosol must assume an active form. Proteasomes are activated when ubiquitylated substrates bind to them and interact with the proteasome-bound deubiquitylase Usp14/Ubp6. The resulting increase in the proteasome's degradative activity was recently shown to be mediated by Usp14's ubiquitin-like (Ubl) domain, which, by itself, can trigger proteasome activation. Many other proteins with diverse cellular functions also contain Ubl domains and can associate with 26S proteasomes. We therefore tested if various Ubl-containing proteins that have important roles in protein homeostasis or disease also activate 26S proteasomes. All seven Ubl-containing proteins tested-the shuttling factors Rad23A, Rad23B, and Ddi2; the deubiquitylase Usp7, the ubiquitin ligase Parkin, the cochaperone Bag6, and the protein phosphatase UBLCP1-stimulated peptide hydrolysis two- to fivefold. Rather than enhancing already active proteasomes, Rad23B and its Ubl domain activated previously latent 26S particles. Also, Ubl-containing proteins (if present with an unfolded protein) increased proteasomal adenosine 5'-triphosphate (ATP) hydrolysis, the step which commits substrates to degradation. Surprisingly, some of these proteins also could stimulate peptide hydrolysis even when their Ubl domains were deleted. However, their Ubl domains were required for the increased ATPase activity. Thus, upon binding to proteasomes, Ubl-containing proteins not only deliver substrates (e.g., the shuttling factors) or provide additional enzymatic activities (e.g., Parkin) to proteasomes, but also increase their capacity for proteolysis.
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38
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Shi J, Hu X, Guo Y, Wang L, Ji J, Li J, Zhang ZR. A technique for delineating the unfolding requirements for substrate entry into retrotranslocons during endoplasmic reticulum-associated degradation. J Biol Chem 2019; 294:20084-20096. [PMID: 31748412 DOI: 10.1074/jbc.ra119.010019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 11/13/2019] [Indexed: 11/06/2022] Open
Abstract
The endoplasmic reticulum-associated degradation (ERAD) pathway mediates the endoplasmic reticulum-to-cytosol retrotranslocation of defective proteins through protein complexes called retrotranslocons. Defective proteins usually have complex conformations and topologies, and it is unclear how ERAD can thread these conformationally diverse protein substrates through the retrotranslocons. Here, we investigated the substrate conformation flexibility necessary for transport via retrotranslocons on the ERAD-L, ERAD-M, and HIV-encoded protein Vpu-hijacked ERAD branches. To this end, we appended various ERAD substrates with specific domains whose conformations were tunable in flexibility or tightness by binding to appropriate ligands. With this technique, we could define the capacity of specific retrotranslocons in disentangling very tight, less tight but well-folded, and unstructured conformations. The Hrd1 complex, the retrotranslocon on the ERAD-L branch, permitted the passage of substrates with a proteinase K-resistant tight conformation, whereas the E3 ligase gp78-mediated ERAD-M allowed passage only of nearly completely disordered but not well-folded substrates and thus may have the least unfoldase activity. Vpu-mediated ERAD, containing a potential retrotranslocon, could unfold well-folded substrates for successful retrotranslocation. However, substrate retrotranslocation in Vpu-mediated ERAD was blocked by enhanced conformational tightness of the substrate. On the basis of these findings, we propose a mechanism underlying polypeptide movement through the endoplasmic reticulum membrane. We anticipate that our biochemical system paves the way for identifying the factors necessary for the retrotranslocation of membrane proteins.
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Affiliation(s)
- Junfen Shi
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China.,University of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China
| | - Xianyan Hu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China.,University of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China
| | - Yuan Guo
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China.,University of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China
| | - Linhan Wang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China.,University of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China
| | - Jia Ji
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China.,University of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China
| | - Jiqiang Li
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China.,University of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China
| | - Zai-Rong Zhang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China .,University of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China
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Morozov AV, Karpov VL. Proteasomes and Several Aspects of Their Heterogeneity Relevant to Cancer. Front Oncol 2019; 9:761. [PMID: 31456945 PMCID: PMC6700291 DOI: 10.3389/fonc.2019.00761] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 07/29/2019] [Indexed: 01/19/2023] Open
Abstract
The life of every organism is dependent on the fine-tuned mechanisms of protein synthesis and breakdown. The degradation of most intracellular proteins is performed by the ubiquitin proteasome system (UPS). Proteasomes are central elements of the UPS and represent large multisubunit protein complexes directly responsible for the protein degradation. Accumulating data indicate that there is an intriguing diversity of cellular proteasomes. Different proteasome forms, containing different subunits and attached regulators have been described. In addition, proteasomes specific for a particular tissue were identified. Cancer cells are highly dependent on the proper functioning of the UPS in general, and proteasomes in particular. At the same time, the information regarding the role of different proteasome forms in cancer is limited. This review describes the functional and structural heterogeneity of proteasomes, their association with cancer as well as several established and novel proteasome-directed therapeutic strategies.
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Affiliation(s)
- Alexey V. Morozov
- Laboratory of Regulation of Intracellular Proteolysis, W.A. Engelhardt Institute of Molecular Biology RAS, Moscow, Russia
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40
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Gottlieb CD, Thompson ACS, Ordureau A, Harper JW, Kopito RR. Acute unfolding of a single protein immediately stimulates recruitment of ubiquitin protein ligase E3C (UBE3C) to 26S proteasomes. J Biol Chem 2019; 294:16511-16524. [PMID: 31375563 DOI: 10.1074/jbc.ra119.009654] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 07/16/2019] [Indexed: 01/26/2023] Open
Abstract
The intracellular accumulation of aggregated misfolded proteins is a cytopathological hallmark of neurodegenerative diseases. However, the functional relationship between protein misfolding or aggregation and the cellular proteostasis network that monitors and maintains proteome health is poorly understood. Previous studies have associated translational suppression and transcriptional remodeling with the appearance of protein aggregates, but whether these responses are induced by aggregates or their misfolded monomeric or oligomeric precursors remains unclear. Because aggregation in cells is rapid, nonlinear, and asynchronous, it has not been possible to deconvolve these kinetically linked processes to determine the earliest cellular responses to misfolded proteins. Upon removal of the synthetic, biologically inert ligand shield-1 (S1), AgDD, an engineered variant FK506-binding protein (FKBP1A), rapidly (t ½ ∼5 min) unfolds and self-associates, forming detergent-insoluble, microscopic cytoplasmic aggregates. Using global diglycine-capture (K-GG) proteomics, we found here that this solubility transition is associated with immediate increases in ubiquitylation of AgDD itself, along with that of endogenous proteins that are components of the ribosome and the 26S proteasome. We also found that the earliest cellular responses to acute S1 removal include recruitment of ubiquitin protein ligase E3C (UBE3C) to the 26S proteasome and ubiquitylation of two key proteasomal ubiquitin receptors, 26S proteasome regulatory subunit RPN10 (RPN10) and Rpn13 homolog (RPN13 or ADRM1). We conclude that these proteasomal responses are due to AgDD protein misfolding and not to the presence of detergent-insoluble aggregates.
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Affiliation(s)
- Colin D Gottlieb
- Department of Biology, Stanford University, Stanford, California 94305
| | | | - Alban Ordureau
- Department of Cell Biology, Blavatnik Institute of Harvard Medical School, Boston, Massachusetts 02115
| | - J Wade Harper
- Department of Cell Biology, Blavatnik Institute of Harvard Medical School, Boston, Massachusetts 02115
| | - Ron R Kopito
- Department of Biology, Stanford University, Stanford, California 94305
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Kors S, Geijtenbeek K, Reits E, Schipper-Krom S. Regulation of Proteasome Activity by (Post-)transcriptional Mechanisms. Front Mol Biosci 2019; 6:48. [PMID: 31380390 PMCID: PMC6646590 DOI: 10.3389/fmolb.2019.00048] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/11/2019] [Indexed: 12/23/2022] Open
Abstract
Intracellular protein synthesis, folding, and degradation are tightly controlled processes to ensure proper protein homeostasis. The proteasome is responsible for the degradation of the majority of intracellular proteins, which are often targeted for degradation via polyubiquitination. However, the degradation rate of proteins is also affected by the capacity of proteasomes to recognize and degrade these substrate proteins. This capacity is regulated by a variety of proteasome modulations including (1) changes in complex composition, (2) post-translational modifications, and (3) altered transcription of proteasomal subunits and activators. Various diseases are linked to proteasome modulation and altered proteasome function. A better understanding of these modulations may offer new perspectives for therapeutic intervention. Here we present an overview of these three proteasome modulating mechanisms to give better insight into the diversity of proteasomes.
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Affiliation(s)
- Suzan Kors
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Karlijne Geijtenbeek
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Eric Reits
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Sabine Schipper-Krom
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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Aristizábal D, Rivas V, Cassab GI, Lledías F. Heat stress reveals high molecular mass proteasomes in Arabidopsis thaliana suspension cells cultures. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 140:78-87. [PMID: 31085449 DOI: 10.1016/j.plaphy.2019.04.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/01/2019] [Accepted: 04/26/2019] [Indexed: 06/09/2023]
Abstract
Because of their sessile nature, plants have evolved complex and robust mechanisms to respond to adverse environments. Stress conditions trigger an increase in protein turnover and degradation. Proteasomes are essential to the cell for removing, in a highly regulated manner, partially denatured or oxidized proteins thus minimizing their cytotoxicity. We observed that suspension cells of Arabidopsis thaliana treated with high temperature (37 °C) directed the assembly of high molecular mass proteasomes. The removal of a 75% of the original ubiquitin conjugates and the maintenance of protein carbonyls at basal levels correlated with a specific proteasome profiles. The profiles obtained by the separation of different proteasomes populations by Blue-Native Polyacrylamide Gel Electrophoresis and western blot analysis suggest that synthesis, assembly, and heavy ubiquitination of 20S (CP) subunits are promoted by heat stress.
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Affiliation(s)
- Daniel Aristizábal
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Mor, 62250, Mexico
| | - Viridiana Rivas
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Mor, 62250, Mexico
| | - Gladys I Cassab
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Mor, 62250, Mexico
| | - Fernando Lledías
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Mor, 62250, Mexico.
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43
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Marshall RS, Vierstra RD. Dynamic Regulation of the 26S Proteasome: From Synthesis to Degradation. Front Mol Biosci 2019; 6:40. [PMID: 31231659 PMCID: PMC6568242 DOI: 10.3389/fmolb.2019.00040] [Citation(s) in RCA: 141] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 05/09/2019] [Indexed: 01/12/2023] Open
Abstract
All eukaryotes rely on selective proteolysis to control the abundance of key regulatory proteins and maintain a healthy and properly functioning proteome. Most of this turnover is catalyzed by the 26S proteasome, an intricate, multi-subunit proteolytic machine. Proteasomes recognize and degrade proteins first marked with one or more chains of poly-ubiquitin, the addition of which is actuated by hundreds of ligases that individually identify appropriate substrates for ubiquitylation. Subsequent proteasomal digestion is essential and influences a myriad of cellular processes in species as diverse as plants, fungi and humans. Importantly, dysfunction of 26S proteasomes is associated with numerous human pathologies and profoundly impacts crop performance, thus making an understanding of proteasome dynamics critically relevant to almost all facets of human health and nutrition. Given this widespread significance, it is not surprising that sophisticated mechanisms have evolved to tightly regulate 26S proteasome assembly, abundance and activity in response to demand, organismal development and stress. These include controls on transcription and chaperone-mediated assembly, influences on proteasome localization and activity by an assortment of binding proteins and post-translational modifications, and ultimately the removal of excess or damaged particles via autophagy. Intriguingly, the autophagic clearance of damaged 26S proteasomes first involves their modification with ubiquitin, thus connecting ubiquitylation and autophagy as key regulatory events in proteasome quality control. This turnover is also influenced by two distinct biomolecular condensates that coalesce in the cytoplasm, one attracting damaged proteasomes for autophagy, and the other reversibly storing proteasomes during carbon starvation to protect them from autophagic clearance. In this review, we describe the current state of knowledge regarding the dynamic regulation of 26S proteasomes at all stages of their life cycle, illustrating how protein degradation through this proteolytic machine is tightly controlled to ensure optimal growth, development and longevity.
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Affiliation(s)
- Richard S Marshall
- Department of Biology, Washington University in St. Louis, St. Louis, MO, United States
| | - Richard D Vierstra
- Department of Biology, Washington University in St. Louis, St. Louis, MO, United States
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44
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Tomita T, Matouschek A. Substrate selection by the proteasome through initiation regions. Protein Sci 2019; 28:1222-1232. [PMID: 31074920 DOI: 10.1002/pro.3642] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/03/2019] [Accepted: 05/06/2019] [Indexed: 01/04/2023]
Abstract
Proteins in the cell have to be eliminated once their function is no longer desired or they become damaged. Most regulated protein degradation is achieved by a large enzymatic complex called the proteasome. Many proteasome substrates are targeted for degradation by the covalent attachment of ubiquitin molecules. Ubiquitinated proteins can be bound by the proteasome, but for proteolysis to occur the proteasome needs to find a disordered tail somewhere in the target at which it initiates degradation. The initiation step contributes to the specificity of proteasomal degradation. Here, we review how the proteasome selects initiation sites within its substrates and discuss how the initiation step affects physiological processes.
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Affiliation(s)
- Takuya Tomita
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, 78712
| | - Andreas Matouschek
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, 78712
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45
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Kim HT, Collins GA, Goldberg AL. Measurement of the Multiple Activities of 26S Proteasomes. Methods Mol Biol 2019; 1844:289-308. [PMID: 30242717 DOI: 10.1007/978-1-4939-8706-1_19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Because proteasomes catalyze most of the protein degradation in mammalian cells, and their functioning is essential for cellular homeostasis, proteasome structure, biochemical mechanisms, and regulation in normal and disease states are now widely studied and are of major importance. In addition, inhibitors of the proteasome's peptidase activity have proven to be very valuable as research tools and in the treatment of hematologic malignancies, and a number of newer pharmacological agents that alter proteasome function are being developed. The rapid degradation of ubiquitinated proteins by the 26S proteasome involves multiple enzymatic and non-enzymatic steps, including the binding of ubiquitinated substrates to the 19S particle (Subheading 3.2), opening the gated substrate entry channel into the 20S particle (Subheading 3.3), disassembly of the Ub chain (Subheading 3.4), ATP hydrolysis (Subheading 3.5), substrate unfolding and translocation, and proteolysis within the 20S particle (Subheadings 3.3 and 3.7). Assaying each of these processes is important if we are to fully understand the physiological regulation of proteasome function and the effects of disease or drugs. Here, we describe several methods that we have found useful to measure many of these individual activities using purified proteasomes. Studies using these approaches have already provided valuable new insights into the effects of post-synthetic modifications to 26S subunits, the physiological regulation of the ubiquitin-proteasome system, and the impairment of proteasome activity in neurodegenerative disease. These advances would not have been possible if only the standard assays of peptidase activity were used.
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Affiliation(s)
- Hyoung Tae Kim
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | | | - Alfred L Goldberg
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA.
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46
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Abstract
The ubiquitin proteasome system (UPS) degrades individual proteins in a highly regulated fashion and is responsible for the degradation of misfolded, damaged, or unneeded cellular proteins. During the past 20 years, investigators have established a critical role for the UPS in essentially every cellular process, including cell cycle progression, transcriptional regulation, genome integrity, apoptosis, immune responses, and neuronal plasticity. At the center of the UPS is the proteasome, a large and complex molecular machine containing a multicatalytic protease complex. When the efficiency of this proteostasis system is perturbed, misfolded and damaged protein aggregates can accumulate to toxic levels and cause neuronal dysfunction, which may underlie many neurodegenerative diseases. In addition, many cancers rely on robust proteasome activity for degrading tumor suppressors and cell cycle checkpoint inhibitors necessary for rapid cell division. Thus, proteasome inhibitors have proven clinically useful to treat some types of cancer, especially multiple myeloma. Numerous cellular processes rely on finely tuned proteasome function, making it a crucial target for future therapeutic intervention in many diseases, including neurodegenerative diseases, cystic fibrosis, atherosclerosis, autoimmune diseases, diabetes, and cancer. In this review, we discuss the structure and function of the proteasome, the mechanisms of action of different proteasome inhibitors, various techniques to evaluate proteasome function in vitro and in vivo, proteasome inhibitors in preclinical and clinical development, and the feasibility for pharmacological activation of the proteasome to potentially treat neurodegenerative disease.
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Affiliation(s)
- Tiffany A Thibaudeau
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia
| | - David M Smith
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia
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47
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Bard JAM, Bashore C, Dong KC, Martin A. The 26S Proteasome Utilizes a Kinetic Gateway to Prioritize Substrate Degradation. Cell 2019; 177:286-298.e15. [PMID: 30929903 DOI: 10.1016/j.cell.2019.02.031] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 12/22/2018] [Accepted: 02/19/2019] [Indexed: 11/28/2022]
Abstract
The 26S proteasome is the principal macromolecular machine responsible for protein degradation in eukaryotes. However, little is known about the detailed kinetics and coordination of the underlying substrate-processing steps of the proteasome, and their correlation with observed conformational states. Here, we used reconstituted 26S proteasomes with unnatural amino-acid-attached fluorophores in a series of FRET- and anisotropy-based assays to probe substrate-proteasome interactions, the individual steps of the processing pathway, and the conformational state of the proteasome itself. We develop a complete kinetic picture of proteasomal degradation, which reveals that the engagement steps prior to substrate commitment are fast relative to subsequent deubiquitination, translocation, and unfolding. Furthermore, we find that non-ideal substrates are rapidly rejected by the proteasome, which thus employs a kinetic proofreading mechanism to ensure degradation fidelity and substrate prioritization.
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Affiliation(s)
- Jared A M Bard
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA; California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Charlene Bashore
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA; California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Ken C Dong
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA; California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Andreas Martin
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA; California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA 94720, USA.
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48
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Caputi FF, Rullo L, Stamatakos S, Candeletti S, Romualdi P. Interplay between the Endogenous Opioid System and Proteasome Complex: Beyond Signaling. Int J Mol Sci 2019; 20:ijms20061441. [PMID: 30901925 PMCID: PMC6470665 DOI: 10.3390/ijms20061441] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/13/2019] [Accepted: 03/19/2019] [Indexed: 02/07/2023] Open
Abstract
Intracellular signaling mechanisms underlying the opioid system regulation of nociception, neurotransmitters release, stress responses, depression, and the modulation of reward circuitry have been investigated from different points of view. The presence of the ubiquitin proteasome system (UPS) in the synaptic terminations suggest a potential role of ubiquitin-dependent mechanisms in the control of the membrane occupancy by G protein-coupled receptors (GPCRs), including those belonging to the opioid family. In this review, we focused our attention on the role played by the ubiquitination processes and by UPS in the modulation of opioid receptor signaling and in pathological conditions involving the endogenous opioid system. The collective evidence here reported highlights the potential usefulness of proteasome inhibitors in neuropathic pain, addictive behavior, and analgesia since these molecules can reduce pain behavioral signs, heroin self-administration, and the development of morphine analgesic tolerance. Moreover, the complex mechanisms involved in the effects induced by opioid agonists binding to their receptors include the ubiquitination process as a post-translational modification which plays a relevant role in receptor trafficking and degradation. Hence, UPS modulation may offer novel opportunities to control the balance between therapeutic versus adverse effects evoked by opioid receptor activation, thus, representing a promising druggable target.
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Affiliation(s)
- Francesca Felicia Caputi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Irnerio 48, 40126 Bologna, Italy.
| | - Laura Rullo
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Irnerio 48, 40126 Bologna, Italy.
| | - Serena Stamatakos
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Irnerio 48, 40126 Bologna, Italy.
| | - Sanzio Candeletti
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Irnerio 48, 40126 Bologna, Italy.
| | - Patrizia Romualdi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Irnerio 48, 40126 Bologna, Italy.
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49
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Lin H, Ruan GY, Sun XQ, Chen XY, Zheng X, Sun PM. Effects of RNAi-induced Skp2 inhibition on cell cycle, apoptosis and proliferation of endometrial carcinoma cells. Exp Ther Med 2019; 17:3441-3450. [PMID: 30988723 PMCID: PMC6447788 DOI: 10.3892/etm.2019.7392] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 02/11/2019] [Indexed: 02/07/2023] Open
Abstract
The aim of the current study was to investigate the underlying mechanism of S-phase kinase associated protein 2 (Skp2) gene inhibition by lentivirus-mediated RNA interference (RNAi) on the cell cycle, apoptosis and proliferation of endometrial carcinoma HEC-1-A cells. A lentivirus shRNA vector targeting Skp2 was constructed and transfected into HEC-1-A cells. HEC-1-A cells transfected with a scramble sequence were used as negative controls. The mRNA and protein expression of Skp2, p27, cyclin D1 and caspase-3 were detected via reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. The effects of Skp2 inhibition on the cell cycle, apoptosis and proliferation of HEC-1-A cells were detected using flow cytometry and a cell counting kit-8. Skp2 co-expression data was analyzed using Oncomine and TCGA databases. The positive recombinant viral clones were identified via PCR and confirmed via sequencing. The mRNA and protein expression of Skp2 were significantly decreased in HEC-1-A cells transfected with the lentiviral vectors compared with the negative control. In addition, there were no significant changes in the mRNA expression of p27 and cyclin D1; however, the protein levels of p27 and cyclin D1 were upregulated and downregulated, respectively, in HEC-1-A cells transfected with lentiviral vectors compared with negative controls. RNAi-induced Skp2 inhibition exerted an anti-proliferative effect by inducing cell cycle arrest, however cell apoptosis was not significantly affected. In the TCGA database, Skp2 expression positively associated with IGF2R, IGF2BP3, IGFBP1 and CCNF, while Skp2 expression negatively associated with IGF2, IGFBP6, IGFBP7 and IGFBP3. RNAi-induced Skp2 inhibition upregulated the protein expression of p27 and downregulated the protein expression of cyclin D1. The expression of Skp2 in endometrial cancer may therefore be regulated by the insulin-like growth factor 1 receptor signaling pathway.
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Affiliation(s)
- Hao Lin
- Department of Gynecology, Fujian Provincial Maternity and Children's Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
| | - Guan-Yu Ruan
- Laboratory of Gynecologic Oncology, Fujian Provincial Maternity and Children's Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
| | - Xiao-Qi Sun
- Department of Gynecology, Fujian Provincial Maternity and Children's Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
| | - Xiao-Ying Chen
- Department of Gynecology, Fujian Provincial Maternity and Children's Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
| | - Xiu Zheng
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
| | - Peng-Ming Sun
- Department of Gynecology, Fujian Provincial Maternity and Children's Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350001, P.R. China.,Laboratory of Gynecologic Oncology, Fujian Provincial Maternity and Children's Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
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Li B, Li M, Wu J, Xu X. Transcriptomic analysis of differentially expressed genes in the oriental armyworm Mythimna separata Walker at different temperatures. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2019; 30:186-195. [PMID: 30889494 DOI: 10.1016/j.cbd.2019.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 01/14/2019] [Accepted: 01/14/2019] [Indexed: 11/19/2022]
Abstract
The oriental armyworm Mythimna separata Walker is a serious migratory and polyphagous pest that damages major crops and some pastures from the family Gramineae. Temperature is a crucial abiotic factor that affects its survival, development and reproduction, but the thermal responses of this moth at the molecular level are largely unknown. In this research, we sequenced the transcriptomes of oriental armyworms that were reared at three temperatures (20 °C, 25 °C and 30 °C) using an Illumina high-throughput RNA-sequencing (RNA-seq) method. We obtained 54.0 Gb of clean reads and 113,396 transcripts. From a total of 46,681 unigenes identified, 22,911 were annotated to the non-redundant (NR) database. We identified 333 downregulated and 1588 upregulated genes in 20 °C versus 25 °C, and 1096 downregulated and 875 upregulated genes at 30 °C versus 25 °C by differential expression of genes (DEGs). GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analyses revealed several functional terms related to carbohydrate metabolism, energy metabolism, and xenobiotics metabolism. DEGs involved in glycolysis, the citrate cycle, oxidative phosphorylation, and the composition of myofilaments were significantly downregulated, while most heat shock protein genes (HSPs) and genes in the ubiquitin-mediated proteasome pathway were upregulated at 30 °C. Many cytochrome P450 monooxygenase genes (CYPs) in clan 3 were upregulated at 20 °C, while two genes involved in ecdysteroid biosynthesis, CYP302A1 and CYP315A1, were upregulated at 30 °C. These data may improve the understanding of the complex molecular mechanisms involved in the thermal responses of M. separata.
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Affiliation(s)
- Boliao Li
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Plant Protection, Northwest A&F University, No. 3 Taicheng Road, 712100 Yangling, Shaanxi, China
| | - Meimei Li
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Plant Protection, Northwest A&F University, No. 3 Taicheng Road, 712100 Yangling, Shaanxi, China
| | - Junxiang Wu
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Plant Protection, Northwest A&F University, No. 3 Taicheng Road, 712100 Yangling, Shaanxi, China.
| | - Xiangli Xu
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Plant Protection, Northwest A&F University, No. 3 Taicheng Road, 712100 Yangling, Shaanxi, China.
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