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Deb W, Rosenfelt C, Vignard V, Papendorf JJ, Möller S, Wendlandt M, Studencka-Turski M, Cogné B, Besnard T, Ruffier L, Toutain B, Poirier L, Cuinat S, Kritzer A, Crunk A, diMonda J, Vengoechea J, Mercier S, Kleinendorst L, van Haelst MM, Zuurbier L, Sulem T, Katrínardóttir H, Friðriksdóttir R, Sulem P, Stefansson K, Jonsdottir B, Zeidler S, Sinnema M, Stegmann APA, Naveh N, Skraban CM, Gray C, Murrell JR, Isikay S, Pehlivan D, Calame DG, Posey JE, Nizon M, McWalter K, Lupski JR, Isidor B, Bolduc FV, Bézieau S, Krüger E, Küry S, Ebstein F. PSMD11 loss-of-function variants correlate with a neurobehavioral phenotype, obesity, and increased interferon response. Am J Hum Genet 2024; 111:1352-1369. [PMID: 38866022 PMCID: PMC11267520 DOI: 10.1016/j.ajhg.2024.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 05/15/2024] [Accepted: 05/16/2024] [Indexed: 06/14/2024] Open
Abstract
Primary proteasomopathies have recently emerged as a new class of rare early-onset neurodevelopmental disorders (NDDs) caused by pathogenic variants in the PSMB1, PSMC1, PSMC3, or PSMD12 proteasome genes. Proteasomes are large multi-subunit protein complexes that maintain cellular protein homeostasis by clearing ubiquitin-tagged damaged, misfolded, or unnecessary proteins. In this study, we have identified PSMD11 as an additional proteasome gene in which pathogenic variation is associated with an NDD-causing proteasomopathy. PSMD11 loss-of-function variants caused early-onset syndromic intellectual disability and neurodevelopmental delay with recurrent obesity in 10 unrelated children. Our findings demonstrate that the cognitive impairment observed in these individuals could be recapitulated in Drosophila melanogaster with depletion of the PMSD11 ortholog Rpn6, which compromised reversal learning. Our investigations in subject samples further revealed that PSMD11 loss of function resulted in impaired 26S proteasome assembly and the acquisition of a persistent type I interferon (IFN) gene signature, mediated by the integrated stress response (ISR) protein kinase R (PKR). In summary, these data identify PSMD11 as an additional member of the growing family of genes associated with neurodevelopmental proteasomopathies and provide insights into proteasomal biology in human health.
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Affiliation(s)
- Wallid Deb
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France; Nantes Université, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - Cory Rosenfelt
- Department of Pediatrics, University of Alberta, Edmonton, AB T6G 1C9, Canada
| | - Virginie Vignard
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France; Nantes Université, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - Jonas Johannes Papendorf
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
| | - Sophie Möller
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
| | - Martin Wendlandt
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
| | - Maja Studencka-Turski
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
| | - Benjamin Cogné
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France; Nantes Université, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - Thomas Besnard
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France; Nantes Université, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - Léa Ruffier
- Nantes Université, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - Bérénice Toutain
- Nantes Université, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - Léa Poirier
- Nantes Université, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - Silvestre Cuinat
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France; Nantes Université, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - Amy Kritzer
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA, USA
| | | | - Janette diMonda
- Department of Human Genetics, School of Medicine, Emory University, Atlanta, GA, USA
| | - Jaime Vengoechea
- Department of Human Genetics, School of Medicine, Emory University, Atlanta, GA, USA
| | - Sandra Mercier
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France; Nantes Université, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - Lotte Kleinendorst
- Amsterdam Reproduction & Development Research Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Emma Center for Personalized Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Mieke M van Haelst
- Amsterdam Reproduction & Development Research Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Emma Center for Personalized Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Department of Human Genetics, Amsterdam UMC, Amsterdam UMC, Location AMC, Amsterdam, the Netherlands
| | - Linda Zuurbier
- Amsterdam Reproduction & Development Research Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Department of Human Genetics, Amsterdam UMC, Amsterdam UMC, Location AMC, Amsterdam, the Netherlands
| | - Telma Sulem
- deCODE Genetics/Amgen, Inc., Reykjavik, Iceland
| | | | | | | | | | - Berglind Jonsdottir
- Childrens Hospital Hringurinn, National University Hospital of Iceland, Reykjavik, Iceland
| | - Shimriet Zeidler
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Margje Sinnema
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Alexander P A Stegmann
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Natali Naveh
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Cara M Skraban
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, USA; Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA; Departments of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Christopher Gray
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, USA; Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Jill R Murrell
- Department of Pathology and Laboratory Medicine, Children's Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Sedat Isikay
- Division of Pediatric Neurology, Department of Pediatrics, Gaziantep Islam, Science and Technology University Faculty of Medicine, Gaziantep, Türkiye
| | - Davut Pehlivan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Daniel G Calame
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Jennifer E Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mathilde Nizon
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France; Nantes Université, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | | | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Bertrand Isidor
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France; Nantes Université, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - François V Bolduc
- Department of Pediatrics, University of Alberta, Edmonton, AB T6G 1C9, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada; Department of Medical Genetics, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Stéphane Bézieau
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France; Nantes Université, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - Elke Krüger
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany.
| | - Sébastien Küry
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France; Nantes Université, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - Frédéric Ebstein
- Nantes Université, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France; Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany.
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2
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Al Rawi S, Simpson L, Agnarsdóttir G, McDonald NQ, Chernuha V, Elpeleg O, Zeviani M, Barker RA, Spiegel R, Laman H. Study of an FBXO7 patient mutation reveals Fbxo7 and PI31 co-regulate proteasomes and mitochondria. FEBS J 2024; 291:2565-2589. [PMID: 38466799 DOI: 10.1111/febs.17114] [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: 12/06/2023] [Revised: 01/18/2024] [Accepted: 02/29/2024] [Indexed: 03/13/2024]
Abstract
Mutations in FBXO7 have been discovered to be associated with an atypical parkinsonism. We report here a new homozygous missense mutation in a paediatric patient that causes an L250P substitution in the dimerisation domain of Fbxo7. This alteration selectively ablates the Fbxo7-PI31 interaction and causes a significant reduction in Fbxo7 and PI31 levels in patient cells. Consistent with their association with proteasomes, patient fibroblasts have reduced proteasome activity and proteasome subunits. We also show PI31 interacts with the MiD49/51 fission adaptor proteins, and unexpectedly, PI31 acts to facilitate SCFFbxo7-mediated ubiquitination of MiD49. The L250P mutation reduces the SCFFbxo7 ligase-mediated ubiquitination of a subset of its known substrates. Although MiD49/51 expression was reduced in patient cells, there was no effect on the mitochondrial network. However, patient cells show reduced levels of mitochondrial function and mitophagy, higher levels of ROS and are less viable under stress. Our study demonstrates that Fbxo7 and PI31 regulate proteasomes and mitochondria and reveals a new function for PI31 in enhancing the SCFFbxo7 E3 ubiquitin ligase activity.
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Affiliation(s)
- Sara Al Rawi
- Department of Pathology, University of Cambridge, UK
| | - Lorna Simpson
- Department of Pathology, University of Cambridge, UK
| | | | - Neil Q McDonald
- Signalling and Structural Biology Laboratory, The Francis Crick Institute, London, UK
- Department of Biological Sciences, Institute of Structural and Molecular Biology, London, UK
| | - Veronika Chernuha
- Pediatric Neurology Institute, Dana-Dwek Children's Hospital, Tel Aviv Medical Centre and Sackler Faculty of Medicine, Israel
| | - Orly Elpeleg
- Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Massimo Zeviani
- Mitochondrial Biology Unit, The MRC and University of Cambridge, UK
| | - Roger A Barker
- John van Geest Centre for Brain Repair, Cambridge, UK
- Wellcome-MRC Cambridge Stem Cell Institute, UK
| | - Ronen Spiegel
- Pediatric Department, Emek Medical Center, Afula, Israel
| | - Heike Laman
- Department of Pathology, University of Cambridge, UK
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3
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Wang J, Kjellgren A, DeMartino GN. Differential Interactions of the Proteasome Inhibitor PI31 with Constitutive and Immuno-20S Proteasomes. Biochemistry 2024; 63:1000-1015. [PMID: 38577872 DOI: 10.1021/acs.biochem.3c00707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
PI31 (Proteasome Inhibitor of 31,000 Da) is a 20S proteasome binding protein originally identified as an in vitro inhibitor of 20S proteasome proteolytic activity. Recently reported cryo-electron microscopy structures of 20S-PI31 complexes have revealed that the natively disordered proline-rich C-terminus of PI31 enters the central chamber in the interior of the 20S proteasome and interacts directly with the proteasome's multiple catalytic threonine residues in a manner predicted to inhibit their enzymatic function while evading its own proteolysis. Higher eukaryotes express an alternative form of the 20S proteasome (termed "immuno-proteasome") that features genetically and functionally distinct catalytic subunits. The effect of PI31 on immuno-proteasome function is unknown. We examine the relative inhibitory effects of PI31 on purified constitutive (20Sc) and immuno-(20Si) 20S proteasomes in vitro and show that PI31 inhibits 20Si hydrolytic activity to a significantly lesser degree than that of 20Sc. Unlike 20Sc, 20Si hydrolyzes the carboxyl-terminus of PI31 and this effect contributes to the reduced inhibitory activity of PI31 toward 20Si. Conversely, loss of 20Sc inhibition by PI31 point mutants leads to PI31 degradation by 20Sc. These results demonstrate unexpected differential interactions of PI31 with 20Sc and 20Si and document their functional consequences.
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Affiliation(s)
- Jason Wang
- Department of Physiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, Texas 75390-9040, United States
| | - Abbey Kjellgren
- Department of Physiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, Texas 75390-9040, United States
| | - George N DeMartino
- Department of Physiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, Texas 75390-9040, United States
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4
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Wang L, Yan M, Bu T, Wu X, Li L, Silvestrini B, Sun F, Cheng CY, Chen H. Map-1a regulates Sertoli cell BTB dynamics through the cytoskeletal organization of microtubule and F-actin. Reprod Biol Endocrinol 2024; 22:36. [PMID: 38570783 PMCID: PMC10988971 DOI: 10.1186/s12958-024-01204-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 03/11/2024] [Indexed: 04/05/2024] Open
Abstract
Microtubule-associated protein 1a (Map1a) is a microtubule (MT) regulatory protein that binds to the MT protofilaments in mammalian cells to promote MT stabilization. Maps work with MT cleavage proteins and other MT catastrophe-inducing proteins to confer MT dynamics to support changes in the Sertoli cell shape to sustain spermatogenesis. However, no functional studies are found in the literature to probe its role in spermatogenesis. Using an RNAi approach, coupled with the use of toxicant-induced testis (in vivo)- and Sertoli cell (in vitro)-injury models, RNA-Seq analysis, transcriptome profiling, and relevant bioinformatics analysis, immunofluorescence analysis, and pertinent biochemical assays for cytoskeletal organization, we have delineated the functional role of Map1a in Sertoli cells and testes. Map1a was shown to support MT structural organization, and its knockdown (KD) also perturbed the structural organization of actin, vimentin, and septin cytoskeletons as these cytoskeletons are intimately related, working in concert to support spermatogenesis. More importantly, cadmium-induced Sertoli cell injury that perturbed the MT structural organization across the cell cytoplasm was associated with disruptive changes in the distribution of Map1a and a surge in p-p38-MAPK (phosphorylated p38-mitogen-activated protein kinase) expression but not total p38-MAPK. These findings thus support the notion that p-p38-MAPK activation is involved in cadmium-induced Sertoli cell injury. This conclusion was supported by studies using doramapimod, a specific p38-MAPK phosphorylation (activation) inhibitor, which was capable of restoring the cadmium-induced disruptive structural organization of MTs across the Sertoli cell cytoplasm. In summary: this study provides mechanistic insights regarding restoration of toxicant-induced Sertoli cell and testis injury and male infertility.
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Affiliation(s)
- Lingling Wang
- Institute of Reproductive Medicine, Medical School of Nantong University, Nantong, 226001, Jiangsu, China
| | - Ming Yan
- Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, 210009, Jiangsu, China
| | - Tiao Bu
- Institute of Reproductive Medicine, Medical School of Nantong University, Nantong, 226001, Jiangsu, China
| | - Xiaolong Wu
- Department of Urology and Andrology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, Zhejiang, China
| | - Linxi Li
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Zhejiang 325027, Wenzhou, China
| | - Bruno Silvestrini
- Faculty of Pharmacy, University of Rome La Sapienza, P. Le Aldo Moro 5, 00185, Rome, Italy
| | - Fei Sun
- Institute of Reproductive Medicine, Medical School of Nantong University, Nantong, 226001, Jiangsu, China.
| | - C Yan Cheng
- Institute of Reproductive Medicine, Medical School of Nantong University, Nantong, 226001, Jiangsu, China.
| | - Hao Chen
- Institute of Reproductive Medicine, Medical School of Nantong University, Nantong, 226001, Jiangsu, China.
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Xiong J, Pang X, Song X, Yang L, Pang C. The coherence between PSMC6 and α-ring in the 26S proteasome is associated with Alzheimer's disease. Front Mol Neurosci 2024; 16:1330853. [PMID: 38357597 PMCID: PMC10864545 DOI: 10.3389/fnmol.2023.1330853] [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: 10/31/2023] [Accepted: 12/22/2023] [Indexed: 02/16/2024] Open
Abstract
Alzheimer's disease (AD) is a heterogeneous age-dependent neurodegenerative disorder. Its hallmarks involve abnormal proteostasis, which triggers proteotoxicity and induces neuronal dysfunction. The 26S proteasome is an ATP-dependent proteolytic nanomachine of the ubiquitin-proteasome system (UPS) and contributes to eliminating these abnormal proteins. This study focused on the relationship between proteasome and AD, the hub genes of proteasome, PSMC6, and 7 genes of α-ring, are selected as targets to study. The following three characteristics were observed: 1. The total number of proteasomes decreased with AD progression because the proteotoxicity damaged the expression of proteasome proteins, as evidenced by the downregulation of hub genes. 2. The existing proteasomes exhibit increased activity and efficiency to counterbalance the decline in total proteasome numbers, as evidenced by enhanced global coordination and reduced systemic disorder of proteasomal subunits as AD advances. 3. The synergy of PSMC6 and α-ring subunits is associated with AD. Synergistic downregulation of PSMC6 and α-ring subunits reflects a high probability of AD risk. Regarding the above discovery, the following hypothesis is proposed: The aggregation of pathogenic proteins intensifies with AD progression, then proteasome becomes more active and facilitates the UPS selectively targets the degradation of abnormal proteins to maintain CNS proteostasis. In this paper, bioinformatics and support vector machine learning methods are applied and combined with multivariate statistical analysis of microarray data. Additionally, the concept of entropy was used to detect the disorder of proteasome system, it was discovered that entropy is down-regulated continually with AD progression against system chaos caused by AD. Another conception of the matrix determinant was used to detect the global coordination of proteasome, it was discovered that the coordination is enhanced to maintain the efficiency of degradation. The features of entropy and determinant suggest that active proteasomes resist the attack caused by AD like defenders, on the one hand, to protect themselves (entropy reduces), and on the other hand, to fight the enemy (determinant reduces). It is noted that these are results from biocomputing and need to be supported by further biological experiments.
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Affiliation(s)
- Jing Xiong
- College of Computer Science, Sichuan Normal University, Chengdu, China
| | - Xinping Pang
- West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, China
| | - Xianghu Song
- College of Computer Science, Sichuan Normal University, Chengdu, China
| | - Lin Yang
- College of Computer Science, Sichuan Normal University, Chengdu, China
| | - Chaoyang Pang
- College of Computer Science, Sichuan Normal University, Chengdu, China
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Elabd S, Pauletto E, Solozobova V, Eickhoff N, Padrao N, Zwart W, Blattner C. TRIM25 targets p300 for degradation. Life Sci Alliance 2023; 6:e202301980. [PMID: 37770115 PMCID: PMC10539465 DOI: 10.26508/lsa.202301980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 09/18/2023] [Accepted: 09/19/2023] [Indexed: 10/01/2023] Open
Abstract
p300 is an important transcriptional co-factor. By stimulating the transfer of acetyl residues onto histones and several key transcription factors, p300 enhances transcriptional initiation and impacts cellular processes including cell proliferation and cell division. Despite its importance for cellular homeostasis, its regulation is poorly understood. We show that TRIM25, a member of the TRIM protein family, targets p300 for proteasomal degradation. However, despite TRIM25's RING domain and E3 activity, degradation of p300 by TRIM25 is independent of TRIM25-mediated p300 ubiquitination. Instead, TRIM25 promotes the interaction of p300 with dynein, which ensures a microtubule-dependent transport of p300 to cellular proteasomes. Through mediating p300 degradation, TRIM25 affects p300-dependent gene expression.
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Affiliation(s)
- Seham Elabd
- Institute for Biological and Chemical Systems - Biological Information Processing, Karlsruhe, Germany
- https://ror.org/00mzz1w90 Human Physiology Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Eleonora Pauletto
- Institute for Biological and Chemical Systems - Biological Information Processing, Karlsruhe, Germany
| | - Valeria Solozobova
- Institute for Biological and Chemical Systems - Biological Information Processing, Karlsruhe, Germany
| | - Nils Eickhoff
- Division of Oncogenomics, Oncode Institute, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Nuno Padrao
- Division of Oncogenomics, Oncode Institute, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Wilbert Zwart
- Division of Oncogenomics, Oncode Institute, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Christine Blattner
- Institute for Biological and Chemical Systems - Biological Information Processing, Karlsruhe, Germany
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7
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Nemec AA, Tomko RJ. An unstructured proteasome inhibitor comes into focus. J Biol Chem 2023; 299:105145. [PMID: 37562568 PMCID: PMC10463253 DOI: 10.1016/j.jbc.2023.105145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2023] [Indexed: 08/12/2023] Open
Abstract
The inhibitory mechanism of an intrinsically disordered proteasome inhibitor identified over 30 years ago has finally been revealed by cryo-electron microscopy by Hsu et al. in a recent report in the Journal of Biological Chemistry. The structure, coupled with biochemical and cell-based experiments, resolves lingering questions about how the inhibitor achieves multisite inhibition of proteasomal protease activity, while raising several exciting new questions on the nature of proteasome subpopulations in the process.
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Affiliation(s)
- Antonia A Nemec
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida, USA.
| | - Robert J Tomko
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida, USA.
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8
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Navarro-Martínez A, Vicente-García C, Carvajal JJ. NMJ-related diseases beyond the congenital myasthenic syndromes. Front Cell Dev Biol 2023; 11:1216726. [PMID: 37601107 PMCID: PMC10436495 DOI: 10.3389/fcell.2023.1216726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/21/2023] [Indexed: 08/22/2023] Open
Abstract
Neuromuscular junctions (NMJs) are a special type of chemical synapse that transmits electrical stimuli from motor neurons (MNs) to their innervating skeletal muscle to induce a motor response. They are an ideal model for the study of synapses, given their manageable size and easy accessibility. Alterations in their morphology or function lead to neuromuscular disorders, such as the congenital myasthenic syndromes, which are caused by mutations in proteins located in the NMJ. In this review, we highlight novel potential candidate genes that may cause or modify NMJs-related pathologies in humans by exploring the phenotypes of hundreds of mouse models available in the literature. We also underscore the fact that NMJs may differ between species, muscles or even sexes. Hence the importance of choosing a good model organism for the study of NMJ-related diseases: only taking into account the specific features of the mammalian NMJ, experimental results would be efficiently translated to the clinic.
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Affiliation(s)
| | - Cristina Vicente-García
- Centro Andaluz de Biología del Desarrollo, CSIC-UPO-JA, Universidad Pablo de Olavide, Sevilla, Spain
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9
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Smith G, Sweeney ST, O’Kane CJ, Prokop A. How neurons maintain their axons long-term: an integrated view of axon biology and pathology. Front Neurosci 2023; 17:1236815. [PMID: 37564364 PMCID: PMC10410161 DOI: 10.3389/fnins.2023.1236815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 07/06/2023] [Indexed: 08/12/2023] Open
Abstract
Axons are processes of neurons, up to a metre long, that form the essential biological cables wiring nervous systems. They must survive, often far away from their cell bodies and up to a century in humans. This requires self-sufficient cell biology including structural proteins, organelles, and membrane trafficking, metabolic, signalling, translational, chaperone, and degradation machinery-all maintaining the homeostasis of energy, lipids, proteins, and signalling networks including reactive oxygen species and calcium. Axon maintenance also involves specialised cytoskeleton including the cortical actin-spectrin corset, and bundles of microtubules that provide the highways for motor-driven transport of components and organelles for virtually all the above-mentioned processes. Here, we aim to provide a conceptual overview of key aspects of axon biology and physiology, and the homeostatic networks they form. This homeostasis can be derailed, causing axonopathies through processes of ageing, trauma, poisoning, inflammation or genetic mutations. To illustrate which malfunctions of organelles or cell biological processes can lead to axonopathies, we focus on axonopathy-linked subcellular defects caused by genetic mutations. Based on these descriptions and backed up by our comprehensive data mining of genes linked to neural disorders, we describe the 'dependency cycle of local axon homeostasis' as an integrative model to explain why very different causes can trigger very similar axonopathies, providing new ideas that can drive the quest for strategies able to battle these devastating diseases.
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Affiliation(s)
- Gaynor Smith
- Cardiff University, School of Medicine, College of Biomedical and Life Sciences, Cardiff, United Kingdom
| | - Sean T. Sweeney
- Department of Biology, University of York and York Biomedical Research Institute, York, United Kingdom
| | - Cahir J. O’Kane
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Andreas Prokop
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biology, The University of Manchester, Manchester, United Kingdom
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10
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Kraus F, Goodall EA, Smith IR, Jiang Y, Paoli JC, Adolf F, Zhang J, Paulo JA, Schulman BA, Harper JW. PARK15/FBXO7 is dispensable for PINK1/Parkin mitophagy in iNeurons and HeLa cell systems. EMBO Rep 2023:e56399. [PMID: 37334901 PMCID: PMC10398645 DOI: 10.15252/embr.202256399] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 05/16/2023] [Accepted: 06/01/2023] [Indexed: 06/21/2023] Open
Abstract
The protein kinase PINK1 and ubiquitin ligase Parkin promote removal of damaged mitochondria via a feed-forward mechanism involving ubiquitin (Ub) phosphorylation (pUb), Parkin activation, and ubiquitylation of mitochondrial outer membrane proteins to support the recruitment of mitophagy receptors. The ubiquitin ligase substrate receptor FBXO7/PARK15 is mutated in an early-onset parkinsonian-pyramidal syndrome. Previous studies have proposed a role for FBXO7 in promoting Parkin-dependent mitophagy. Here, we systematically examine the involvement of FBXO7 in depolarization and mt UPR-dependent mitophagy in the well-established HeLa and induced-neurons cell systems. We find that FBXO7-/- cells have no demonstrable defect in: (i) kinetics of pUb accumulation, (ii) pUb puncta on mitochondria by super-resolution imaging, (iii) recruitment of Parkin and autophagy machinery to damaged mitochondria, (iv) mitophagic flux, and (v) mitochondrial clearance as quantified by global proteomics. Moreover, global proteomics of neurogenesis in the absence of FBXO7 reveals no obvious alterations in mitochondria or other organelles. These results argue against a general role for FBXO7 in Parkin-dependent mitophagy and point to the need for additional studies to define how FBXO7 mutations promote parkinsonian-pyramidal syndrome.
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Affiliation(s)
- Felix Kraus
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
| | - Ellen A Goodall
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
| | - Ian R Smith
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Yizhi Jiang
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Julia C Paoli
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Frank Adolf
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Jiuchun Zhang
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Joao A Paulo
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Brenda A Schulman
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - J Wade Harper
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
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11
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Sun C, Desch K, Nassim-Assir B, Giandomenico SL, Nemcova P, Langer JD, Schuman EM. An abundance of free regulatory (19 S) proteasome particles regulates neuronal synapses. Science 2023; 380:eadf2018. [PMID: 37228199 DOI: 10.1126/science.adf2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 04/04/2023] [Indexed: 05/27/2023]
Abstract
The proteasome, the major protein-degradation machine in cells, regulates neuronal synapses and long-term information storage. Here, using super-resolution microscopy, we found that the two essential subcomplexes of the proteasome, the regulatory (19S) and catalytic (20S) particles, are differentially distributed within individual rat cortical neurons. We discovered an unexpected abundance of free 19S particles near synapses. The free neuronal 19S particles bind and deubiquitylate lysine 63-ubiquitin (Lys63-ub), a non-proteasome-targeting ubiquitin linkage. Pull-down assays revealed a significant overrepresentation of synaptic molecules as Lys63-ub interactors. Inhibition of the 19S deubiquitylase activity significantly altered excitatory synaptic transmission and reduced the synaptic availability of AMPA receptors at multiple trafficking points in a proteasome-independent manner. Together, these results reveal a moonlighting function of the regulatory proteasomal subcomplex near synapses.
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Affiliation(s)
- Chao Sun
- Max Planck Institute for Brain Research, 60438 Frankfurt am Main, Germany
| | - Kristina Desch
- Max Planck Institute for Brain Research, 60438 Frankfurt am Main, Germany
| | | | | | - Paulina Nemcova
- Max Planck Institute for Brain Research, 60438 Frankfurt am Main, Germany
| | - Julian D Langer
- Max Planck Institute for Brain Research, 60438 Frankfurt am Main, Germany
- Max Planck Institute for Biophysics, 60438 Frankfurt am Main, Germany
| | - Erin M Schuman
- Max Planck Institute for Brain Research, 60438 Frankfurt am Main, Germany
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12
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Hsu HC, Wang J, Kjellgren A, Li H, DeMartino GN. Ηigh-resolution structure of mammalian PI31-20S proteasome complex reveals mechanism of proteasome inhibition. J Biol Chem 2023:104862. [PMID: 37236357 PMCID: PMC10319324 DOI: 10.1016/j.jbc.2023.104862] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/08/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
Proteasome-catalyzed protein degradation mediates and regulates critical aspects of many cellular functions and is an important element of proteostasis in health and disease. Proteasome function is determined in part by the types of proteasome holoenzymes formed between the 20S core particle that catalyzes peptide bond hydrolysis and any of multiple regulatory proteins to which it binds. One of these regulators, PI31, was previously identified as an in vitro 20S proteasome inhibitor, but neither the molecular mechanism nor the possible physiologic significance of PI31-mediated proteasome inhibition has been clear. Here we report a high-resolution cryo-EM structure of the mammalian 20S proteasome in complex with PI31. The structure shows that two copies of the intrinsically-disordered carboxyl-terminus of PI31 are present in the central cavity of the closed-gate conformation of the proteasome and interact with proteasome catalytic sites in a manner that blocks proteolysis of substrates but resists their own degradation. The two inhibitory polypeptide chains appear to originate from PI31 monomers that enter the catalytic chamber from opposite ends of the 20S cylinder. We present evidence that PI31 can inhibit proteasome activity in mammalian cells and may serve regulatory functions for the control of cellular proteostasis.
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Affiliation(s)
- Hao-Chi Hsu
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI 49503
| | - Jason Wang
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390
| | - Abbey Kjellgren
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI 49503.
| | - George N DeMartino
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390.
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13
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Hsu HC, Wang J, Kjellgren A, Li H, DeMartino GN. High-resolution structure of mammalian PI31â€"20S proteasome complex reveals mechanism of proteasome inhibition. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.03.535455. [PMID: 37066326 PMCID: PMC10103979 DOI: 10.1101/2023.04.03.535455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Proteasome-catalyzed protein degradation mediates and regulates critical aspects of many cellular functions and is an important element of proteostasis in health and disease. Proteasome function is determined in part by the types of proteasome holoenzymes formed between the 20S core particle that catalyzes peptide bond hydrolysis and any of multiple regulatory proteins to which it binds. One of these regulators, PI31, was previously identified as an in vitro 20S proteasome inhibitor, but neither the molecular mechanism nor the possible physiologic significance of PI31-mediated proteasome inhibition has been clear. Here we report a high- resolution cryo-EM structure of the mammalian 20S proteasome in complex with PI31. The structure shows that two copies of the intrinsically-disordered carboxyl-terminus of PI31 are present in the central cavity of the closed-gate conformation of the proteasome and interact with proteasome catalytic sites in a manner that blocks proteolysis of substrates but resists their own degradation. The two inhibitory polypeptide chains appear to originate from PI31 monomers that enter the catalytic chamber from opposite ends of the 20S cylinder. We present evidence that PI31 can inhibit proteasome activity in mammalian cells and may serve regulatory functions for the control of cellular proteostasis.
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14
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Sato B, Kim J, Morohoshi K, Kang W, Miyado K, Tsuruta F, Kawano N, Chiba T. Proteasome-Associated Proteins, PA200 and ECPAS, Are Essential for Murine Spermatogenesis. Biomolecules 2023; 13:biom13040586. [PMID: 37189334 DOI: 10.3390/biom13040586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/16/2023] [Accepted: 03/22/2023] [Indexed: 05/17/2023] Open
Abstract
Proteasomes are highly sophisticated protease complexes that degrade non-lysosomal proteins, and their proper regulation ensures various biological functions such as spermatogenesis. The proteasome-associated proteins, PA200 and ECPAS, are predicted to function during spermatogenesis; however, male mice lacking each of these genes sustain fertility, raising the possibility that these proteins complement each other. To address this issue, we explored these possible roles during spermatogenesis by producing mice lacking these genes (double-knockout mice; dKO mice). Expression patterns and quantities were similar throughout spermatogenesis in the testes. In epididymal sperm, PA200 and ECPAS were expressed but were differentially localized to the midpiece and acrosome, respectively. Proteasome activity was considerably reduced in both the testes and epididymides of dKO male mice, resulting in infertility. Mass spectrometric analysis revealed LPIN1 as a target protein for PA200 and ECPAS, which was confirmed via immunoblotting and immunostaining. Furthermore, ultrastructural and microscopic analyses demonstrated that the dKO sperm displayed disorganization of the mitochondrial sheath. Our results indicate that PA200 and ECPAS work cooperatively during spermatogenesis and are essential for male fertility.
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Affiliation(s)
- Ban Sato
- Master's and Doctoral Program in Biology, Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8577, Japan
- Laboratory of Regulatory Biology, Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Kawasaki 214-8571, Japan
| | - Jiwoo Kim
- College of Biological Sciences, School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8577, Japan
| | - Kazunori Morohoshi
- Laboratory of Regulatory Biology, Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Kawasaki 214-8571, Japan
| | - Woojin Kang
- Department of Reproductive Biology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya 157-8535, Japan
| | - Kenji Miyado
- Department of Reproductive Biology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya 157-8535, Japan
| | - Fuminori Tsuruta
- Master's and Doctoral Program in Biology, Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8577, Japan
| | - Natsuko Kawano
- Laboratory of Regulatory Biology, Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Kawasaki 214-8571, Japan
| | - Tomoki Chiba
- Master's and Doctoral Program in Biology, Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8577, Japan
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15
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Buneeva OA, Kopylov AT, Medvedev AE. Proteasome Interactome and Its Role in the Mechanisms of Brain Plasticity. BIOCHEMISTRY (MOSCOW) 2023; 88:319-336. [PMID: 37076280 DOI: 10.1134/s0006297923030033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/28/2023]
Abstract
Abstract
Proteasomes are highly conserved multienzyme complexes responsible for proteolytic degradation of the short-lived, regulatory, misfolded, and damaged proteins. They play an important role in the processes of brain plasticity, and decrease in their function is accompanied by the development of neurodegenerative pathology. Studies performed in different laboratories both on cultured mammalian and human cells and on preparations of the rat and rabbit brain cortex revealed a large number of proteasome-associated proteins. Since the identified proteins belong to certain metabolic pathways, multiple enrichment of the proteasome fraction with these proteins indicates their important role in proteasome functioning. Extrapolation of the experimental data, obtained on various biological objects, to the human brain suggests that the proteasome-associated proteins account for at least 28% of the human brain proteome. The proteasome interactome of the brain contains a large number of proteins involved in the assembly of these supramolecular complexes, regulation of their functioning, and intracellular localization, which could be changed under different conditions (for example, during oxidative stress) or in different phases of the cell cycle. In the context of molecular functions of the Gene Ontology (GO) Pathways, the proteins of the proteasome interactome mediate cross-talk between components of more than 30 metabolic pathways annotated in terms of GO. The main result of these interactions is binding of adenine and guanine nucleotides, crucial for realization of the nucleotide-dependent functions of the 26S and 20S proteasomes. Since the development of neurodegenerative pathology is often associated with regioselective decrease in the functional activity of proteasomes, a positive therapeutic effect would be obviously provided by the factors increasing proteasomal activity. In any case, pharmacological regulation of the brain proteasomes seems to be realized through the changes in composition and/or activity of the proteins associated with proteasomes (deubiquitinase, PKA, CaMKIIα, etc.).
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Affiliation(s)
- Olga A Buneeva
- Institute of Biomedical Chemistry, Moscow, 119121, Russia
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16
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Esfahanian N, Nelson M, Autenried R, Pattison JS, Callegari E, Rezvani K. Comprehensive Analysis of Proteasomal Complexes in Mouse Brain Regions Detects ENO2 as a Potential Partner of the Proteasome in the Striatum. Cell Mol Neurobiol 2022; 42:2305-2319. [PMID: 34037901 PMCID: PMC8617079 DOI: 10.1007/s10571-021-01106-2] [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: 02/11/2021] [Accepted: 05/19/2021] [Indexed: 11/28/2022]
Abstract
Defects in the activity of the proteasome or its regulators are linked to several pathologies, including neurodegenerative diseases. We hypothesize that proteasome heterogeneity and its selective partners vary across brain regions and have a significant impact on proteasomal catalytic activities. Using neuronal cell cultures and brain tissues obtained from mice, we compared proteasomal activities from two distinct brain regions affected in neurodegenerative diseases, the striatum and the hippocampus. The results indicated that proteasome activities and their responses to proteasome inhibitors are determined by their subcellular localizations and their brain regions. Using an iodixanol gradient fractionation method, proteasome complexes were isolated, followed by proteomic analysis for proteasomal interaction partners. Proteomic results revealed brain region-specific non-proteasomal partners, including gamma-enolase (ENO2). ENO2 showed more association to proteasome complexes purified from the striatum than to those from the hippocampus. These results highlight a potential key role for non-proteasomal partners of proteasomes regarding the diverse activities of the proteasome complex recorded in several brain regions.
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Affiliation(s)
- Niki Esfahanian
- Division of Basic Biomedical Sciences, Sanford School of Medicine,, University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD, 57069, USA
| | - Morgan Nelson
- Division of Basic Biomedical Sciences, Sanford School of Medicine,, University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD, 57069, USA
| | - Rebecca Autenried
- Division of Basic Biomedical Sciences, Sanford School of Medicine,, University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD, 57069, USA
| | - J Scott Pattison
- Division of Basic Biomedical Sciences, Sanford School of Medicine,, University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD, 57069, USA
| | - Eduardo Callegari
- Division of Basic Biomedical Sciences, Sanford School of Medicine,, University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD, 57069, USA
| | - Khosrow Rezvani
- Division of Basic Biomedical Sciences, Sanford School of Medicine,, University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD, 57069, USA.
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17
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Yeast PI31 inhibits the proteasome by a direct multisite mechanism. Nat Struct Mol Biol 2022; 29:791-800. [PMID: 35927584 PMCID: PMC9399903 DOI: 10.1038/s41594-022-00808-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 06/24/2022] [Indexed: 02/06/2023]
Abstract
Proteasome inhibitors are widely used as therapeutics and research tools, and typically target one of the three active sites, each present twice in the proteasome complex. An endogeneous proteasome inhibitor, PI31, was identified 30 years ago, but its inhibitory mechanism has remained unclear. Here, we identify the mechanism of Saccharomyces cerevisiae PI31, also known as Fub1. Using cryo-electron microscopy (cryo-EM), we show that the conserved carboxy-terminal domain of Fub1 is present inside the proteasome's barrel-shaped core particle (CP), where it simultaneously interacts with all six active sites. Targeted mutations of Fub1 disrupt proteasome inhibition at one active site, while leaving the other sites unaffected. Fub1 itself evades degradation through distinct mechanisms at each active site. The gate that allows substrates to access the CP is constitutively closed, and Fub1 is enriched in mutant CPs with an abnormally open gate, suggesting that Fub1 may function to neutralize aberrant proteasomes, thereby ensuring the fidelity of proteasome-mediated protein degradation.
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18
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Keeping Synapses in Shape: Degradation Pathways in the Healthy and Aging Brain. Neuronal Signal 2022; 6:NS20210063. [PMID: 35813265 PMCID: PMC9208270 DOI: 10.1042/ns20210063] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 11/17/2022] Open
Abstract
Synapses maintain their molecular composition, plasticity and function through the concerted action of protein synthesis and removal. The complex and polarized neuronal architecture poses specific challenges to the logistics of protein and organelle turnover since protein synthesis and degradation mainly happen in the cell soma. In addition, post-mitotic neurons accumulate damage over a lifetime, challenging neuronal degradative pathways and making them particularly susceptible to the effects of aging. This review will summarize the current knowledge on neuronal protein turnover mechanisms with a particular focus on the presynapse, including the proteasome, autophagy and the endolysosomal route and their roles in regulating presynaptic proteostasis and function. In addition, the author will discuss how physiological brain aging, which entails a progressive decline in cognitive functions, affects synapses and the degradative machinery.
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19
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Proteasome complexes experience profound structural and functional rearrangements throughout mammalian spermatogenesis. Proc Natl Acad Sci U S A 2022; 119:e2116826119. [PMID: 35377789 PMCID: PMC9169623 DOI: 10.1073/pnas.2116826119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
The proteasome is responsible for the homeostasis of intracellular proteins. Here, we describe structural and functional aspects of a poorly characterized proteasome subtype found exclusively in germ cells. The spermatoproteasome was recently shown to be essential for spermatogenesis, a process requiring intense proteolysis. It differs from the constitutive proteasome by only one subunit, α4s, a subunit that replaces its α4 ubiquitous counterpart. In this work, we show how the shift from α4 to α4s regulates proteasome composition, dynamics, interactome, and activity. We reveal a regulation process more complex than previously suggested, which provides the basis for structural and functional studies of the spermatoproteasome. During spermatogenesis, spermatogonia undergo a series of mitotic and meiotic divisions on their path to spermatozoa. To achieve this, a succession of processes requiring high proteolytic activity are in part orchestrated by the proteasome. The spermatoproteasome (s20S) is specific to the developing gametes, in which the gamete-specific α4s subunit replaces the α4 isoform found in the constitutive proteasome (c20S). Although the s20S is conserved across species and was shown to be crucial for germ cell development, its mechanism, function, and structure remain incompletely characterized. Here, we used advanced mass spectrometry (MS) methods to map the composition of proteasome complexes and their interactomes throughout spermatogenesis. We observed that the s20S becomes highly activated as germ cells enter meiosis, mainly through a particularly extensive 19S activation and, to a lesser extent, PA200 binding. Additionally, the proteasome population shifts from c20S (98%) to s20S (>82 to 92%) during differentiation, presumably due to the shift from α4 to α4s expression. We demonstrated that s20S, but not c20S, interacts with components of the meiotic synaptonemal complex, where it may localize via association with the PI31 adaptor protein. In vitro, s20S preferentially binds to 19S and displays higher trypsin- and chymotrypsin-like activities, both with and without PA200 activation. Moreover, using MS methods to monitor protein dynamics, we identified significant differences in domain flexibility between α4 and α4s. We propose that these differences induced by α4s incorporation result in significant changes in the way the s20S interacts with its partners and dictate its role in germ cell differentiation.
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20
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Bogár F, Fülöp L, Penke B. Novel Therapeutic Target for Prevention of Neurodegenerative Diseases: Modulation of Neuroinflammation with Sig-1R Ligands. Biomolecules 2022; 12:363. [PMID: 35327555 PMCID: PMC8945408 DOI: 10.3390/biom12030363] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/20/2022] [Accepted: 02/23/2022] [Indexed: 12/13/2022] Open
Abstract
Neurodegenerative diseases (NDDs) are characterized by progressive deterioration of the structure and function of cells and their networks in the nervous system. There are currently no drugs or other treatments that can stop the progression of NDDs. NDDs have many similarities and common pathways, e.g., formation of misfolded amyloid proteins, intra- and extracellular amyloid deposits, and chronic inflammation. Initially, the inflammation process has a cytoprotective function; however, an elevated and prolonged immune response has damaging effects and causes cell death. Neuroinflammation has been a target of drug development for treating and curing NDDs. Treatment of different NDDs with non-steroid anti-inflammatory drugs (NSAIDs) has failed or has given inconsistent results. The use of NSAIDs in diagnosed Alzheimer's disease is currently not recommended. Sigma-1 receptor (Sig-1R) is a novel target for NDD drug development. Sig-1R plays a key role in cellular stress signaling, and it regulates endoplasmic reticulum stress and unfolded protein response. Activation of Sig-1R provides neuroprotection in cell cultures and animal studies. Clinical trials demonstrated that several Sig-1R agonists (pridopidine, ANAVEX3-71, fluvoxamine, dextrometorphan) and their combinations have a neuroprotective effect and slow down the progression of distinct NDDs.
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Affiliation(s)
- Ferenc Bogár
- MTA-SZTE Biomimetic Systems Research Group, Eötvös Loránd Research Network (ELKH), Dóm Square 8, H-6720 Szeged, Hungary;
- Department of Medical Chemistry, University of Szeged, Dóm Square 8, H-6720 Szeged, Hungary;
| | - Lívia Fülöp
- Department of Medical Chemistry, University of Szeged, Dóm Square 8, H-6720 Szeged, Hungary;
| | - Botond Penke
- Department of Medical Chemistry, University of Szeged, Dóm Square 8, H-6720 Szeged, Hungary;
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21
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Guo X. Localized Proteasomal Degradation: From the Nucleus to Cell Periphery. Biomolecules 2022; 12:biom12020229. [PMID: 35204730 PMCID: PMC8961600 DOI: 10.3390/biom12020229] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 01/25/2022] [Accepted: 01/27/2022] [Indexed: 12/31/2022] Open
Abstract
The proteasome is responsible for selective degradation of most cellular proteins. Abundantly present in the cell, proteasomes not only diffuse in the cytoplasm and the nucleus but also associate with the chromatin, cytoskeleton, various membranes and membraneless organelles/condensates. How and why the proteasome gets to these specific subcellular compartments remains poorly understood, although increasing evidence supports the hypothesis that intracellular localization may have profound impacts on the activity, substrate accessibility and stability/integrity of the proteasome. In this short review, I summarize recent advances on the functions, regulations and targeting mechanisms of proteasomes, especially those localized to the nuclear condensates and membrane structures of the cell, and I discuss the biological significance thereof in mediating compartmentalized protein degradation.
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Affiliation(s)
- Xing Guo
- Life Sciences Institute, Zhejiang University, Hangzhou 310058, China;
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Hangzhou 310058, China
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22
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Giandomenico SL, Alvarez-Castelao B, Schuman EM. Proteostatic regulation in neuronal compartments. Trends Neurosci 2021; 45:41-52. [PMID: 34489114 DOI: 10.1016/j.tins.2021.08.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/16/2021] [Accepted: 08/05/2021] [Indexed: 12/16/2022]
Abstract
Neurons continuously adapt to external cues and challenges, including stimulation, plasticity-inducing signals and aging. These adaptations are critical for neuronal physiology and extended survival. Proteostasis is the process by which cells adjust their protein content to achieve the specific protein repertoire necessary for cellular function. Due to their complex morphology and polarized nature, neurons possess unique proteostatic requirements. Proteostatic control in axons and dendrites must be implemented through regulation of protein synthesis and degradation in a decentralized fashion, but at the same time, it requires integration, at least in part, in the soma. Here, we discuss current understanding of neuronal proteostasis, as well as open questions and future directions requiring further exploration.
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Affiliation(s)
| | - Beatriz Alvarez-Castelao
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Madrid, Spain
| | - Erin M Schuman
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany.
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23
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Perez JD, Fusco CM, Schuman EM. A Functional Dissection of the mRNA and Locally Synthesized Protein Population in Neuronal Dendrites and Axons. Annu Rev Genet 2021; 55:183-207. [PMID: 34460296 DOI: 10.1146/annurev-genet-030321-054851] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neurons are characterized by a complex morphology that enables the generation of subcellular compartments with unique biochemical and biophysical properties, such as dendrites, axons, and synapses. To sustain these different compartments and carry a wide array of elaborate operations, neurons express a diverse repertoire of gene products. Extensive regulation at both the messenger RNA (mRNA) and protein levels allows for the differentiation of subcellular compartments as well as numerous forms of plasticity in response to variable stimuli. Among the multiple mechanisms that control cellular functions, mRNA translation is manipulated by neurons to regulate where and when a protein emerges. Interestingly, transcriptomic and translatomic profiles of both dendrites and axons have revealed that the mRNA population only partially predicts the local protein population and that this relation significantly varies between different gene groups. Here, we describe the space that local translation occupies within the large molecular and regulatory complexity of neurons, in contrast to other modes of regulation. We then discuss the specialized organization of mRNAs within different neuronal compartments, as revealed by profiles of the local transcriptome. Finally, we discuss the features and functional implications of both locally correlated-and anticorrelated-mRNA-protein relations both under baseline conditions and during synaptic plasticity. Expected final online publication date for the Annual Review of Genetics, Volume 55 is November 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Julio D Perez
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany;
| | - Claudia M Fusco
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany;
| | - Erin M Schuman
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany;
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24
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Ibañez-Vega J, Del Valle F, Sáez JJ, Guzman F, Diaz J, Soza A, Yuseff MI. Ecm29-Dependent Proteasome Localization Regulates Cytoskeleton Remodeling at the Immune Synapse. Front Cell Dev Biol 2021; 9:650817. [PMID: 34055780 PMCID: PMC8155528 DOI: 10.3389/fcell.2021.650817] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 04/14/2021] [Indexed: 12/25/2022] Open
Abstract
The formation of an immune synapse (IS) enables B cells to capture membrane-tethered antigens, where cortical actin cytoskeleton remodeling regulates cell spreading and depletion of F-actin at the centrosome promotes the recruitment of lysosomes to facilitate antigen extraction. How B cells regulate both pools of actin, remains poorly understood. We report here that decreased F-actin at the centrosome and IS relies on the distribution of the proteasome, regulated by Ecm29. Silencing Ecm29 decreases the proteasome pool associated to the centrosome of B cells and shifts its accumulation to the cell cortex and IS. Accordingly, Ecm29-silenced B cells display increased F-actin at the centrosome, impaired centrosome and lysosome repositioning to the IS and defective antigen extraction and presentation. Ecm29-silenced B cells, which accumulate higher levels of proteasome at the cell cortex, display decreased actin retrograde flow in lamellipodia and enhanced spreading responses. Our findings support a model where B the asymmetric distribution of the proteasome, mediated by Ecm29, coordinates actin dynamics at the centrosome and the IS, promoting lysosome recruitment and cell spreading.
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Affiliation(s)
- Jorge Ibañez-Vega
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Felipe Del Valle
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan José Sáez
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Fanny Guzman
- Núcleo Biotecnología Curauma, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Jheimmy Diaz
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Andrea Soza
- Centro de Biología Celular y Biomedicina, Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
- Centro de Envejecimiento y Regeneración (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - María Isabel Yuseff
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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25
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The proteasome and its role in the nervous system. Cell Chem Biol 2021; 28:903-917. [PMID: 33905676 DOI: 10.1016/j.chembiol.2021.04.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/04/2021] [Accepted: 04/05/2021] [Indexed: 12/14/2022]
Abstract
Proteasomes are multisubunit complexes that catalyze the majority of protein degradation in mammalian cells to maintain protein homeostasis and influence the regulation of most cellular processes. The proteasome, a multicatalytic protease complex, is a ring-like structure with a narrow pore that exhibits regulated gating, enabling the selective degradation of target proteins into peptide fragments. This process of removing proteins is essential for eliminating proteins that are no longer wanted, such as unfolded or aggregated proteins. This is important for preserving cellular function relevant to brain health and disease. Recently, in the nervous system, specialized proteasomes have been shown to generate peptides with important cellular functions. These discoveries challenge the prevailing notion that proteasomes primarily operate to eliminate proteins and identify signaling-competent proteasomes. This review focuses on the structure, function, and regulation of proteasomes and sheds light on emerging areas of investigation regarding the role of proteasomes in the nervous system.
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Jiang J, Liu D, Xu G, Liang T, Yu C, Liao S, Chen L, Huang S, Sun X, Yi M, Zhang Z, Lu Z, Wang Z, Chen J, Chen T, Li H, Yao Y, Chen W, Guo H, Liu C, Zhan X. TRIM68, PIKFYVE, and DYNLL2: The Possible Novel Autophagy- and Immunity-Associated Gene Biomarkers for Osteosarcoma Prognosis. Front Oncol 2021; 11:643104. [PMID: 33968741 PMCID: PMC8101494 DOI: 10.3389/fonc.2021.643104] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/26/2021] [Indexed: 12/16/2022] Open
Abstract
Introduction Osteosarcoma is among the most common orthopedic neoplasms, and currently, there are no adequate biomarkers to predict its prognosis. Therefore, the present study was aimed to identify the prognostic biomarkers for autophagy-and immune-related osteosarcoma using bioinformatics tools for guiding the clinical diagnosis and treatment of this disease. Materials and Methods The gene expression and clinical information data were downloaded from the Public database. The genes associated with autophagy were extracted, followed by the development of a logistic regression model for predicting the prognosis of osteosarcoma using univariate and multivariate COX regression analysis and LASSO regression analysis. The accuracy of the constructed model was verified through the ROC curves, calibration plots, and Nomogram plots. Next, immune cell typing was performed using CIBERSORT to analyze the expression of the immune cells in each sample. For the results obtained from the analysis, we used qRT-PCR validation in two strains of human osteosarcoma cells. Results The screening process identified a total of three genes that fulfilled all the screening criteria. The survival curves of the constructed prognostic model revealed that patients with the high risk presented significantly lower survival than the patients with low risk. Finally, the immune cell component analysis revealed that all three genes were significantly associated with the immune cells. The expressions of TRIM68, PIKFYVE, and DYNLL2 were higher in the osteosarcoma cells compared to the control cells. Finally, we used human pathological tissue sections to validate the expression of the genes modeled in osteosarcoma and paracancerous tissue. Conclusion The TRIM68, PIKFYVE, and DYNLL2 genes can be used as biomarkers for predicting the prognosis of osteosarcoma.
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Affiliation(s)
- Jie Jiang
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Dachang Liu
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Guoyong Xu
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Tuo Liang
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Chaojie Yu
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Shian Liao
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Liyi Chen
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Shengsheng Huang
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Xuhua Sun
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Ming Yi
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Zide Zhang
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Zhaojun Lu
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Zequn Wang
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Jiarui Chen
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Tianyou Chen
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Hao Li
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Yuanlin Yao
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Wuhua Chen
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Hao Guo
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Chong Liu
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Xinli Zhan
- Department of Spinal Orthopedics, The First Clinical Affiliated Hospital of Guangxi Medical University, Nanning, China
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Canovas B, Nebreda AR. Diversity and versatility of p38 kinase signalling in health and disease. Nat Rev Mol Cell Biol 2021; 22:346-366. [PMID: 33504982 PMCID: PMC7838852 DOI: 10.1038/s41580-020-00322-w] [Citation(s) in RCA: 234] [Impact Index Per Article: 78.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2020] [Indexed: 02/06/2023]
Abstract
The ability of cells to deal with different types of stressful situations in a precise and coordinated manner is key for survival and involves various signalling networks. Over the past 25 years, p38 kinases — in particular, p38α — have been implicated in the cellular response to stress at many levels. These span from environmental and intracellular stresses, such as hyperosmolarity, oxidative stress or DNA damage, to physiological situations that involve important cellular changes such as differentiation. Given that p38α controls a plethora of functions, dysregulation of this pathway has been linked to diseases such as inflammation, immune disorders or cancer, suggesting the possibility that targeting p38α could be of therapeutic interest. In this Review, we discuss the organization of this signalling pathway focusing on the diversity of p38α substrates, their mechanisms and their links to particular cellular functions. We then address how the different cellular responses can be generated depending on the signal received and the cell type, and highlight the roles of this kinase in human physiology and in pathological contexts. p38α — the best-characterized member of the p38 kinase family — is a key mediator of cellular stress responses. p38α is activated by a plethora of signals and functions through a multitude of substrates to regulate different cellular behaviours. Understanding context-dependent p38α signalling provides important insights into p38α roles in physiology and pathology.
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Affiliation(s)
- Begoña Canovas
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Angel R Nebreda
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain. .,ICREA, Barcelona, Spain.
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28
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Nuclear P38: Roles in Physiological and Pathological Processes and Regulation of Nuclear Translocation. Int J Mol Sci 2020; 21:ijms21176102. [PMID: 32847129 PMCID: PMC7504396 DOI: 10.3390/ijms21176102] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/20/2020] [Accepted: 08/21/2020] [Indexed: 02/07/2023] Open
Abstract
The p38 mitogen-activated protein kinase (p38MAPK, termed here p38) cascade is a central signaling pathway that transmits stress and other signals to various intracellular targets in the cytoplasm and nucleus. More than 150 substrates of p38α/β have been identified, and this number is likely to increase. The phosphorylation of these substrates initiates or regulates a large number of cellular processes including transcription, translation, RNA processing and cell cycle progression, as well as degradation and the nuclear translocation of various proteins. Being such a central signaling cascade, its dysregulation is associated with many pathologies, particularly inflammation and cancer. One of the hallmarks of p38α/β signaling is its stimulated nuclear translocation, which occurs shortly after extracellular stimulation. Although p38α/β do not contain nuclear localization or nuclear export signals, they rapidly and robustly translocate to the nucleus, and they are exported back to the cytoplasm within minutes to hours. Here, we describe the physiological and pathological roles of p38α/β phosphorylation, concentrating mainly on the ill-reviewed regulation of p38α/β substrate degradation and nuclear translocation. In addition, we provide information on the p38α/β ’s substrates, concentrating mainly on the nuclear targets and their role in p38α/β functions. Finally, we also provide information on the mechanisms of nuclear p38α/β translocation and its use as a therapeutic target for p38α/β-dependent diseases.
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29
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Bhaskar S, Gowda J, Prasanna J, Kumar A. Does altering proteasomal activity and trafficking reduce the arborization mediated specific vulnerability of SNpc dopaminergic neurons of Parkinson's disease? Med Hypotheses 2020; 143:110062. [PMID: 32652429 DOI: 10.1016/j.mehy.2020.110062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/27/2020] [Indexed: 01/15/2023]
Abstract
Parkinson's disease (PD) is a late-onset degenerative neuronal disorder and stands second among the neurological disorders with 1% of the total world population being affected. The disease originates majorly due to compromised function of the dopaminergic (DA) neurons in the Substantia Nigra pars compacta (SNpc), but not the ventral tegmental area (VTA) region of the midbrain. The differential susceptibility for degeneration is majorly attributed to morphological, molecular, and electrophysiological heterogeneity existing in DA neurons of SNpc and VTA. Long-range axonal arborization and a higher number of synapses in SNpc DA neurons make it more vulnerable compared to VTA DA neurons. Studies have shown that a decrease in such axonal arborization places DA neurons at decreased risk in PD. The two well established underlying mechanisms are a) As arborization is an energy-demanding process, increased redistribution of mitochondria to the axonal terminals occurs to satisfy the bioenergetic requirement b) The stabilization of axon-promoting factors at the axonal tip is an essential component for enhancing the arborization process. Interfering with any of these two processes would probably alleviate the degeneration of SNpc DA neurons. To accomplish the decreased stability of arborizing factors and thereby increase the resilience of SNpc DA neurons, we hypothesize the activation of anterograde transport-dependent recruitment of proteasomes to axon terminals as one of the most favorable approaches. Understanding this putative avenue of enhancing proteasomal activity and migration to the axonal tip could provide insight into the progression of neurodegeneration in PD and possibly offer a novel therapeutic strategy.
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Affiliation(s)
- Smitha Bhaskar
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Allalsandra, Yelahanka, Bengaluru 560065, Karnataka, India
| | - Jeevan Gowda
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Allalsandra, Yelahanka, Bengaluru 560065, Karnataka, India
| | - Jyothi Prasanna
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Allalsandra, Yelahanka, Bengaluru 560065, Karnataka, India
| | - Anujith Kumar
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Allalsandra, Yelahanka, Bengaluru 560065, Karnataka, India.
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Mohammed JN, Gelles JD, Rubio-Patiño C, Serasinghe MN, Trotta AP, Lockshin RA, Zakeri Z, Chipuk JE. Cell death through the ages: The ICDS 25th Anniversary Meeting. FEBS J 2020; 287:2201-2211. [PMID: 32147971 PMCID: PMC7703806 DOI: 10.1111/febs.15252] [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: 11/25/2019] [Accepted: 02/07/2020] [Indexed: 12/01/2022]
Abstract
In June of 2019, the International Cell Death Society (ICDS) held its 25th anniversary meeting in New York City at the Icahn School of Medicine at Mount Sinai organized by Drs. Richard A. Lockshin (St. John's University, USA), Zahra Zakeri (Queens College, USA), and Jerry Edward Chipuk (Icahn School of Medicine at Mount Sinai, USA). The three-day event, entitled 'Cell death through the ages: The ICDS 25th anniversary meeting', hosted ninety-one delegates including thirty-four speakers and twenty-two poster presentations. Additionally, the organizers gave special recognition to the twenty-one previous ICDS Lifetime Achievement awardees-those who have significantly contributed to the field of cell death and the growth of the organization. Here, we provide a summary of the meeting and highlight trending research in the fields of cell death, autophagy, immunology, and their impact on health and disease.
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Affiliation(s)
- Jarvier N Mohammed
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
- The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
| | - Jesse D Gelles
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
| | - Camila Rubio-Patiño
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
| | - Madhavika N Serasinghe
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
| | - Andrew P Trotta
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
| | - Richard A Lockshin
- Department of Biology, Queens College of the City University of New York, Flushing, NY, USA
| | - Zahra Zakeri
- Department of Biology, Queens College of the City University of New York, Flushing, NY, USA
| | - Jerry E Chipuk
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
- The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
- Department of Dermatology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
- The Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
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Wang X, Meul T, Meiners S. Exploring the proteasome system: A novel concept of proteasome inhibition and regulation. Pharmacol Ther 2020; 211:107526. [PMID: 32173559 DOI: 10.1016/j.pharmthera.2020.107526] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 03/08/2020] [Indexed: 12/13/2022]
Abstract
The proteasome is a well-identified therapeutic target for cancer treatment. It acts as the main protein degradation system in the cell and degrades key mediators of cell growth, survival and function. The term "proteasome" embraces a whole family of distinct complexes, which share a common proteolytic core, the 20S proteasome, but differ by their attached proteasome activators. Each of these proteasome complexes plays specific roles in the control of cellular function. In addition, distinct proteasome interacting proteins regulate proteasome activity in subcellular compartments and in response to cellular signals. Proteasome activators and regulators may thus serve as building blocks to fine-tune proteasome function in the cell according to cellular needs. Inhibitors of the proteasome, e.g. the FDA approved drugs Velcade™, Kyprolis™, Ninlaro™, inactivate the catalytic 20S core and effectively block protein degradation of all proteasome complexes in the cell resulting in inhibition of cell growth and induction of apoptosis. Efficacy of these inhibitors, however, is hampered by their pronounced cytotoxic side-effects as well as by the emerging development of resistance to catalytic proteasome inhibitors. Targeted inhibition of distinct buiding blocks of the proteasome system, i.e. proteasome activators or regulators, represents an alternative strategy to overcome these limitations. In this review, we stress the importance of the diversity of the proteasome complexes constituting an entire proteasome system. Our building block concept provides a rationale for the defined targeting of distinct proteasome super-complexes in disease. We thereby aim to stimulate the development of innovative therapeutic approaches beyond broad catalytic proteasome inhibition.
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Affiliation(s)
- Xinyuan Wang
- Comprehensive Pneumology Center (CPC), University Hospital of the Ludwig-Maximilians-University (LMU) and Helmholtz Zentrum München, German Center for Lung Research (DZL), 81377 Munich, Germany
| | - Thomas Meul
- Comprehensive Pneumology Center (CPC), University Hospital of the Ludwig-Maximilians-University (LMU) and Helmholtz Zentrum München, German Center for Lung Research (DZL), 81377 Munich, Germany
| | - Silke Meiners
- Comprehensive Pneumology Center (CPC), University Hospital of the Ludwig-Maximilians-University (LMU) and Helmholtz Zentrum München, German Center for Lung Research (DZL), 81377 Munich, Germany.
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Coux O, Zieba BA, Meiners S. The Proteasome System in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1233:55-100. [DOI: 10.1007/978-3-030-38266-7_3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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The proteasome regulator PI31 is required for protein homeostasis, synapse maintenance, and neuronal survival in mice. Proc Natl Acad Sci U S A 2019; 116:24639-24650. [PMID: 31754024 PMCID: PMC6900516 DOI: 10.1073/pnas.1911921116] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The conserved proteasome-binding protein PI31 serves as an adapter to couple proteasomes with cellular motors to mediate their transport to distal tips of neurons where protein breakdown occurs. We generated global and conditional PI31 knockout mouse strains and show that this protein is required for protein homeostasis, and that its conditional inactivation in neurons disrupts synaptic structures and long-term survival. This work establishes a critical role for PI31 and local protein degradation in the maintenance of neuronal architecture, circuitry, and function. Because mutations in the PI31 pathway cause neurodegenerative diseases in humans, reduced PI31 activity may contribute to the etiology of these diseases. Proteasome-mediated degradation of intracellular proteins is essential for cell function and survival. The proteasome-binding protein PI31 (Proteasomal Inhibitor of 31kD) promotes 26S assembly and functions as an adapter for proteasome transport in axons. As localized protein synthesis and degradation is especially critical in neurons, we generated a conditional loss of PI31 in spinal motor neurons (MNs) and cerebellar Purkinje cells (PCs). A cKO of PI31 in these neurons caused axon degeneration, neuronal loss, and progressive spinal and cerebellar neurological dysfunction. For both MNs and PCs, markers of proteotoxic stress preceded axonal degeneration and motor dysfunction, indicating a critical role for PI31 in neuronal homeostasis. The time course of the loss of MN and PC function in developing mouse central nervous system suggests a key role for PI31 in human neurodegenerative diseases.
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Sabharwal V, Koushika SP. Crowd Control: Effects of Physical Crowding on Cargo Movement in Healthy and Diseased Neurons. Front Cell Neurosci 2019; 13:470. [PMID: 31708745 PMCID: PMC6823667 DOI: 10.3389/fncel.2019.00470] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 10/02/2019] [Indexed: 01/22/2023] Open
Abstract
High concentration of cytoskeletal filaments, organelles, and proteins along with the space constraints due to the axon's narrow geometry lead inevitably to intracellular physical crowding along the axon of a neuron. Local cargo movement is essential for maintaining steady cargo transport in the axon, and this may be impeded by physical crowding. Molecular motors that mediate active transport share movement mechanisms that allow them to bypass physical crowding present on microtubule tracks. Many neurodegenerative diseases, irrespective of how they are initiated, show increased physical crowding owing to the greater number of stalled organelles and structural changes associated with the cytoskeleton. Increased physical crowding may be a significant factor in slowing cargo transport to synapses, contributing to disease progression and culminating in the dying back of the neuronal process. This review explores the idea that physical crowding can impede cargo movement along the neuronal process. We examine the sources of physical crowding and strategies used by molecular motors that might enable cargo to circumvent physically crowded locations. Finally, we describe sub-cellular changes in neurodegenerative diseases that may alter physical crowding and discuss the implications of such changes on cargo movement.
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Affiliation(s)
| | - Sandhya P. Koushika
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
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35
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Rathje CC, Randle SJ, Al Rawi S, Skinner BM, Nelson DE, Majumdar A, Johnson EEP, Bacon J, Vlazaki M, Affara NA, Ellis PJ, Laman H. A Conserved Requirement for Fbxo7 During Male Germ Cell Cytoplasmic Remodeling. Front Physiol 2019; 10:1278. [PMID: 31649556 PMCID: PMC6795710 DOI: 10.3389/fphys.2019.01278] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 09/23/2019] [Indexed: 12/15/2022] Open
Abstract
Fbxo7 is the substrate-recognition subunit of an SCF-type ubiquitin E3 ligase complex. It has physiologically important functions in regulating mitophagy, proteasome activity and the cell cycle in multiple cell types, like neurons, lymphocytes and erythrocytes. Here, we show that in addition to the previously known Parkinsonian and hematopoietic phenotypes, male mice with reduced Fbxo7 expression are sterile. In these males, despite successful meiosis, nuclear elongation and eviction of histones from chromatin, the developing spermatids are phagocytosed by Sertoli cells during late spermiogenesis, as the spermatids undergo cytoplasmic remodeling. Surprisingly, despite the loss of all germ cells, there was no evidence of the symplast formation and cell sloughing that is typically associated with spermatid death in other mouse sterility models, suggesting that novel cell death and/or cell disposal mechanisms may be engaged in Fbxo7 mutant males. Mutation of the Drosophila Fbxo7 ortholog, nutcracker (ntc) also leads to sterility with germ cell death during cytoplasmic remodeling, indicating that the requirement for Fbxo7 at this stage is conserved. The ntc phenotype was attributed to decreased levels of the proteasome regulator, DmPI31 and reduced proteasome activity. Consistent with the fly model, we observe a reduction in PI31 levels in mutant mice; however, there is no alteration in proteasome activity in whole mouse testes. Our results are consistent with findings that Fbxo7 regulates PI31 protein levels, and indicates that a defect at the late stages of spermiogenesis, possibly due to faulty spatial dynamics of proteasomes during cytoplasmic remodeling, may underlie the fertility phenotype in mice.
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Affiliation(s)
- Claudia C Rathje
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Suzanne J Randle
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Sara Al Rawi
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Benjamin M Skinner
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - David E Nelson
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Antara Majumdar
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Emma E P Johnson
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Joanne Bacon
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Myrto Vlazaki
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Nabeel A Affara
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Peter J Ellis
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Heike Laman
- School of Biosciences, University of Kent, Canterbury, United Kingdom
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