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Bai M, Zhao X, Sahara K, Ohte Y, Hirano Y, Kaneko T, Yashiroda H, Murata S. In-depth Analysis of the Lid Subunits Assembly Mechanism in Mammals. Biomolecules 2019; 9:biom9060213. [PMID: 31159305 PMCID: PMC6627463 DOI: 10.3390/biom9060213] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/21/2019] [Accepted: 05/29/2019] [Indexed: 01/16/2023] Open
Abstract
The 26S proteasome is a key player in the degradation of ubiquitinated proteins, comprising a 20S core particle (CP) and a 19S regulatory particle (RP). The RP is further divided into base and lid subcomplexes, which are assembled independently from each other. We have previously demonstrated the assembly pathway of the CP and the base by observing assembly intermediates resulting from knockdowns of each proteasome subunit and the assembly chaperones. In this study, we examine the assembly pathway of the mammalian lid, which remains to be elucidated. We show that the lid assembly pathway is conserved between humans and yeast. The final step is the incorporation of Rpn12 into the assembly intermediate consisting of two modular complexes, Rpn3-7-15 and Rpn5-6-8-9-11, in both humans and yeast. Furthermore, we dissect the assembly pathways of the two modular complexes by the knockdown of each lid subunit.
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Affiliation(s)
- Minghui Bai
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Xian Zhao
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Kazutaka Sahara
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Yuki Ohte
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Yuko Hirano
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Takeumi Kaneko
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Hideki Yashiroda
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Shigeo Murata
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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Bai M, Zhao X, Sahara K, Ohte Y, Hirano Y, Kaneko T, Yashiroda H, Murata S. Assembly mechanisms of specialized core particles of the proteasome. Biomolecules 2014; 4:662-77. [PMID: 25033340 PMCID: PMC4192667 DOI: 10.3390/biom4030662] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 05/30/2014] [Accepted: 06/22/2014] [Indexed: 11/16/2022] Open
Abstract
The 26S proteasome has a highly complicated structure comprising the 20S core particle (CP) and the 19S regulatory particle (RP). Along with the standard CP in all eukaryotes, vertebrates have two more subtypes of CP called the immunoproteasome and the thymoproteasome. The immunoproteasome has catalytic subunits β1i, β2i, and β5i replacing β1, β2, and β5 and enhances production of major histocompatibility complex I ligands. The thymoproteasome contains thymus-specific subunit β5t in place of β5 or β5i and plays a pivotal role in positive selection of CD8+ T cells. Here we investigate the assembly pathways of the specialized CPs and show that β1i and β2i are incorporated ahead of all the other β-subunits and that both β5i and β5t can be incorporated immediately after the assembly of β3 in the absence of β4, distinct from the assembly of the standard CP in which β-subunits are incorporated in the order of β2, β3, β4, β5, β6, β1, and β7. The propeptide of β5t is a key factor for this earlier incorporation, whereas the body sequence seems to be important for the earlier incorporation of β5i. This unique feature of β5t and β5i may account for preferential assembly of the immunoproteasome and the thymoproteasome over the standard type even when both the standard and specialized subunits are co-expressed.
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Affiliation(s)
- Minghui Bai
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Xian Zhao
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Kazutaka Sahara
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Yuki Ohte
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Yuko Hirano
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Takeumi Kaneko
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Hideki Yashiroda
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Shigeo Murata
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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Kunjappu MJ, Hochstrasser M. Assembly of the 20S proteasome. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:2-12. [PMID: 23507199 DOI: 10.1016/j.bbamcr.2013.03.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 03/02/2013] [Accepted: 03/05/2013] [Indexed: 10/27/2022]
Abstract
The proteasome is a cellular protease responsible for the selective degradation of the majority of the intracellular proteome. It recognizes, unfolds, and cleaves proteins that are destined for removal, usually by prior attachment to polymers of ubiquitin. This macromolecular machine is composed of two subcomplexes, the 19S regulatory particle (RP) and the 20S core particle (CP), which together contain at least 33 different and precisely positioned subunits. How these subunits assemble into functional complexes is an area of active exploration. Here we describe the current status of studies on the assembly of the 20S proteasome (CP). The 28-subunit CP is found in all three domains of life and its cylindrical stack of four heptameric rings is well conserved. Though several CP subunits possess self-assembly properties, a consistent theme in recent years has been the need for dedicated assembly chaperones that promote on-pathway assembly. To date, a minimum of three accessory factors have been implicated in aiding the construction of the 20S proteasome. These chaperones interact with different assembling proteasomal precursors and usher subunits into specific slots in the growing structure. This review will focus largely on chaperone-dependent CP assembly and its regulation. This article is part of a Special Issue entitled: Ubiquitin-Proteasome System. Guest Editors: Thomas Sommer and Dieter H. Wolf.
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Affiliation(s)
- Mary J Kunjappu
- Department of Molecular, Cellular and Developmental Biology, Yale University, 266 Whitney Avenue P.O. Box 208114, New Haven, CT 06520-8114, USA
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Lukic Z, Hausmann S, Sebastian S, Rucci J, Sastri J, Robia SL, Luban J, Campbell EM. TRIM5α associates with proteasomal subunits in cells while in complex with HIV-1 virions. Retrovirology 2011; 8:93. [PMID: 22078707 PMCID: PMC3279310 DOI: 10.1186/1742-4690-8-93] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 11/12/2011] [Indexed: 12/24/2022] Open
Abstract
Background The TRIM5 proteins are cellular restriction factors that prevent retroviral infection in a species-specific manner. Multiple experiments indicate that restriction activity requires accessory host factors, including E2-enzymes. To better understand the mechanism of restriction, we conducted yeast-two hybrid screens to identify proteins that bind to two TRIM5 orthologues. Results The only cDNAs that scored on repeat testing with both TRIM5 orthologues were the proteasome subunit PSMC2 and ubiquitin. Using co-immunoprecipitation assays, we demonstrated an interaction between TRIM5α and PSMC2, as well as numerous other proteasome subunits. Fluorescence microscopy revealed co-localization of proteasomes and TRIM5α cytoplasmic bodies. Forster resonance energy transfer (FRET) analysis indicated that the interaction between TRIM5 and PSMC2 was direct. Previous imaging experiments demonstrated that, when cells are challenged with fluorescently-labeled HIV-1 virions, restrictive TRIM5α orthologues assemble cytoplasmic bodies around incoming virion particles. Following virus challenge, we observed localization of proteasome subunits to rhTRIM5α cytoplasmic bodies that contained fluorescently labeled HIV-1 virions. Conclusions Taken together, the results presented here suggest that localization of the proteasome to TRIM5α cytoplasmic bodies makes an important contribution to TRIM5α-mediated restriction.
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Affiliation(s)
- Zana Lukic
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, USA
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Akazawa H, Komuro I. “Change can happen” by PKA: Proteasomes in in vivo hearts. J Mol Cell Cardiol 2009; 46:445-7. [DOI: 10.1016/j.yjmcc.2008.12.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2008] [Revised: 12/15/2008] [Accepted: 12/20/2008] [Indexed: 01/07/2023]
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Dissecting beta-ring assembly pathway of the mammalian 20S proteasome. EMBO J 2008; 27:2204-13. [PMID: 18650933 DOI: 10.1038/emboj.2008.148] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Accepted: 07/03/2008] [Indexed: 11/09/2022] Open
Abstract
The 20S proteasome is the catalytic core of the 26S proteasome. It comprises four stacked rings of seven subunits each, alpha(1-7)beta(1-7)beta(1-7)alpha(1-7). Recent studies indicated that proteasome-specific chaperones and beta-subunit appendages assist in the formation of alpha-rings and dimerization of half-proteasomes, but the process involved in the assembly of beta-rings is poorly understood. Here, we clarify the mechanism of beta-ring formation on alpha-rings by characterizing assembly intermediates accumulated in cells depleted of each beta-subunit. Starting from beta2, incorporation of beta-subunits occurs in an orderly manner dependent on the propeptides of beta2 and beta5, and the C-terminal tail of beta2. Unexpectedly, hUmp1, a chaperone functioning at the final assembly step, is incorporated as early as beta2 and is required for the structural integrity of early assembly intermediates. We propose a model in which beta-ring formation is assisted by both intramolecular and extrinsic chaperones, whose roles are partially different between yeast and mammals.
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Gopalan B, Shanker M, Scott A, Branch CD, Chada S, Ramesh R. MDA-7/IL-24, a novel tumor suppressor/cytokine is ubiquitinated and regulated by the ubiquitin-proteasome system, and inhibition of MDA-7/IL-24 degradation enhances the antitumor activity. Cancer Gene Ther 2007; 15:1-8. [PMID: 17828282 DOI: 10.1038/sj.cgt.7701095] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Steady-state protein levels are determined by the balance between protein synthesis and degradation. Protein half-lives are determined primarily by degradation, and the major degradation pathways involve either lysosomal destruction or an ATP-dependent process involving ubiquitination to target proteins to the proteosome. Studies have shown that multiple tumor-suppressor proteins are ubiquitinated and degraded by the 26S proteasome. In the present study, we investigated whether the tumor suppressor/cytokine melanoma differentiation-associated gene-7/interleukin-24 gene (MDA-7/IL-24) protein is ubiquitinated and its degradation controlled by the proteasome. Treatment of ovarian (2008) and lung (H1299) tumor cells with adenoviral delivery of mda-7 (Ad-mda7) or Ad-mda7 plus the proteosome inhibitor MG132 showed that MDA-7 protein expression was dependent upon proteosome activity. Western blot and immunoprecipitation analyses verified that the MDA-7 protein was ubiquitinated and that ubiquitinated-MDA-7 levels were increased in MG132-treated cells. These results were confirmed using small interfering RNA (siRNA)-mediated knockdown of ubiquitin. Furthermore, ubiquitinated MDA-7 protein was degraded by the 26S proteasome, as MDA-7 accumulation was observed only when cells were treated with MG132 but not with lysosome or protease inhibitors. Inhibition of the catalytic beta-5 subunit of the 20S proteasome using siRNA resulted in MDA-7 protein accumulation. Finally, treatment of tumor cells with Ad-mda7 plus the proteasome inhibitor bortezomib resulted in increased tumor cell killing. Our results show that MDA-7/IL-24 is ubiquitinated and degraded by the 26S proteasome. Furthermore, inhibition of MDA-7 degradation results in enhanced tumor killing, identifying a novel anticancer strategy.
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Affiliation(s)
- B Gopalan
- Department of Thoracic and Cardiovascular Surgery, The University of Texas, MD Anderson Cancer Center, Houston, TX 77030, USA
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Klare N, Seeger M, Janek K, Jungblut PR, Dahlmann B. Intermediate-type 20 S proteasomes in HeLa cells: "asymmetric" subunit composition, diversity and adaptation. J Mol Biol 2007; 373:1-10. [PMID: 17804016 DOI: 10.1016/j.jmb.2007.07.038] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Revised: 07/13/2007] [Accepted: 07/16/2007] [Indexed: 01/19/2023]
Abstract
The 20 S proteasomes are cylinder-shaped heteromeric dimers with a subunit configuration of alpha7, beta7, beta7, alpha7. Replacement of the three active site-containing standard beta-subunits (beta1, beta2, beta5) by immuno-beta-subunits (beta1i, beta2i, beta5i) results in formation of 20 S immuno-proteasomes, while only partial replacement leads to intermediate-type proteasomes. Synthesis of immuno-subunits can be induced by interferon-gamma, which causes a complete transformation of three subtypes of standard proteasomes into three subtypes of intermediate-type proteasomes in HeLa cells, a process that results in a change in the proteolytic activities of the enzymes. HeLa cells producing the proteasome beta1-subunit tagged with the Fc region-binding ZZ domain of protein A were grown in the presence of interferon-gamma. From these cells, we have purified 20 S proteasomes by using IgG-affinity resin and analysed them by 2D PAGE. Our study showed that subunit replacement can be confined to one half of the proteasome cylinder, resulting in the formation of intermediate-type proteasomes with "asymmetric" subunit composition. Analysis of proteasomes purified from the cytoplasm, nucleoplasm, and microsomes of HeLa S3 cells reveals that all three compartments are furnished with intermediate-type proteasomes of different subtype and subunit composition, exhibiting different specific proteolytic activities.
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Affiliation(s)
- Nicola Klare
- Institut für Biochemie, Charité-Universitätsmedizin-Berlin, Monbijoustrassse 2, 10117 Berlin, Germany
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Le Tallec B, Barrault MB, Courbeyrette R, Guérois R, Marsolier-Kergoat MC, Peyroche A. 20S Proteasome Assembly Is Orchestrated by Two Distinct Pairs of Chaperones in Yeast and in Mammals. Mol Cell 2007; 27:660-74. [PMID: 17707236 DOI: 10.1016/j.molcel.2007.06.025] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Revised: 05/26/2007] [Accepted: 06/21/2007] [Indexed: 11/22/2022]
Abstract
The 20S proteasome is the catalytic core of the 26S proteasome, a central enzyme in the ubiquitin-proteasome system. Its assembly proceeds in a multistep and orderly fashion. Ump1 is the only well-described chaperone dedicated to the assembly of the 20S proteasome in yeast. Here, we report a phenotype related to the DNA damage response that allowed us to isolate four other chaperones of yeast 20S proteasomes, which we named Poc1-Poc4. Poc1/2 and Poc3/4 form two pairs working at different stages in early 20S proteasome assembly. We identify PAC1, PAC2, the recently described PAC3, and an uncharacterized protein that we named PAC4 as functional mammalian homologs of yeast Poc factors. Hence, in yeast as in mammals, proteasome assembly is orchestrated by two pairs of chaperones acting upstream of the half-proteasome maturase Ump1. Our findings provide evidence for a remarkable conservation of a pairwise chaperone-assisted proteasome assembly throughout evolution.
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Affiliation(s)
- Benoît Le Tallec
- CEA, iBiTecS, SBIGeM, Laboratoire du Métabolisme de l'ADN et Réponses aux Génotoxiques, Gif-sur-Yvette, F-91191, France
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Jayarapu K, Griffin TA. Differential intra-proteasome interactions involving standard and immunosubunits. Biochem Biophys Res Commun 2007; 358:867-72. [PMID: 17506986 PMCID: PMC2680721 DOI: 10.1016/j.bbrc.2007.05.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Accepted: 05/02/2007] [Indexed: 11/20/2022]
Abstract
Animals with immune systems have two types of proteasomes, "standard proteasomes" and "immunoproteasomes" that respectively contain constitutively expressed catalytic subunits or interferon-gamma-inducible catalytic subunits. Interestingly, proteasome assembly is biased against formation of most mixed proteasomes containing combinations of standard subunits and immunosubunits. We previously demonstrated that catalytic subunit propeptide differences contribute to this assembly specificity. In the current study, we investigated the contributions of catalytic subunit propeptides and C-terminal extensions to intra-proteasome protein-protein interactions that are potentially involved in mediating biased assembly of human proteasomes, and we found a number of interactions that differentially depended on these structures. For example, the C-terminal extension of standard subunit beta2 is required for beta2's interaction with adjacent beta3, whereas the C-terminal extension of immunosubunit beta2i is dispensable for beta2i's interaction with beta3. Taken together, our results suggest mechanisms whereby differential intra-proteasome interactions could contribute to proteasome assembly specificity.
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Affiliation(s)
| | - Thomas A. Griffin
- Corresponding author: Thomas A. Griffin, William S. Rowe Division of Rheumatology, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, Phone: 1 513 636 3338, Fax: 1 513 636 3328,
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