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Molecular and Structural Basis of the Proteasome α Subunit Assembly Mechanism Mediated by the Proteasome-Assembling Chaperone PAC3-PAC4 Heterodimer

The 26S proteasome is critical for the selective degradation of proteins in eukaryotic cells. This enzyme complex is composed of approximately 70 subunits, including the structurally homologous proteins α1–α7, which combine to form heptameric rings. The correct arrangement of these α subunits is ess...

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Autores principales: Satoh, Tadashi, Yagi-Utsumi, Maho, Okamoto, Kenta, Kurimoto, Eiji, Tanaka, Keiji, Kato, Koichi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6539346/
https://www.ncbi.nlm.nih.gov/pubmed/31067643
http://dx.doi.org/10.3390/ijms20092231
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author Satoh, Tadashi
Yagi-Utsumi, Maho
Okamoto, Kenta
Kurimoto, Eiji
Tanaka, Keiji
Kato, Koichi
author_facet Satoh, Tadashi
Yagi-Utsumi, Maho
Okamoto, Kenta
Kurimoto, Eiji
Tanaka, Keiji
Kato, Koichi
author_sort Satoh, Tadashi
collection PubMed
description The 26S proteasome is critical for the selective degradation of proteins in eukaryotic cells. This enzyme complex is composed of approximately 70 subunits, including the structurally homologous proteins α1–α7, which combine to form heptameric rings. The correct arrangement of these α subunits is essential for the function of the proteasome, but their assembly does not occur autonomously. Assembly of the α subunit is assisted by several chaperones, including the PAC3-PAC4 heterodimer. In this study we showed that the PAC3-PAC4 heterodimer functions as a molecular matchmaker, stabilizing the α4-α5-α6 subcomplex during the assembly of the α-ring. We solved a 0.96-Å atomic resolution crystal structure for a PAC3 homodimer which, in conjunction with nuclear magnetic resonance (NMR) data, highlighted the mobility of the loop comprised of residues 51 to 61. Based on these structural and dynamic data, we created a three-dimensional model of the PAC3-4/α4/α5/α6 quintet complex, and used this model to investigate the molecular and structural basis of the mechanism of proteasome α subunit assembly, as mediated by the PAC3-PAC4 heterodimeric chaperone. Our results provide a potential basis for the development of selective inhibitors against proteasome biogenesis.
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spelling pubmed-65393462019-06-04 Molecular and Structural Basis of the Proteasome α Subunit Assembly Mechanism Mediated by the Proteasome-Assembling Chaperone PAC3-PAC4 Heterodimer Satoh, Tadashi Yagi-Utsumi, Maho Okamoto, Kenta Kurimoto, Eiji Tanaka, Keiji Kato, Koichi Int J Mol Sci Article The 26S proteasome is critical for the selective degradation of proteins in eukaryotic cells. This enzyme complex is composed of approximately 70 subunits, including the structurally homologous proteins α1–α7, which combine to form heptameric rings. The correct arrangement of these α subunits is essential for the function of the proteasome, but their assembly does not occur autonomously. Assembly of the α subunit is assisted by several chaperones, including the PAC3-PAC4 heterodimer. In this study we showed that the PAC3-PAC4 heterodimer functions as a molecular matchmaker, stabilizing the α4-α5-α6 subcomplex during the assembly of the α-ring. We solved a 0.96-Å atomic resolution crystal structure for a PAC3 homodimer which, in conjunction with nuclear magnetic resonance (NMR) data, highlighted the mobility of the loop comprised of residues 51 to 61. Based on these structural and dynamic data, we created a three-dimensional model of the PAC3-4/α4/α5/α6 quintet complex, and used this model to investigate the molecular and structural basis of the mechanism of proteasome α subunit assembly, as mediated by the PAC3-PAC4 heterodimeric chaperone. Our results provide a potential basis for the development of selective inhibitors against proteasome biogenesis. MDPI 2019-05-07 /pmc/articles/PMC6539346/ /pubmed/31067643 http://dx.doi.org/10.3390/ijms20092231 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Satoh, Tadashi
Yagi-Utsumi, Maho
Okamoto, Kenta
Kurimoto, Eiji
Tanaka, Keiji
Kato, Koichi
Molecular and Structural Basis of the Proteasome α Subunit Assembly Mechanism Mediated by the Proteasome-Assembling Chaperone PAC3-PAC4 Heterodimer
title Molecular and Structural Basis of the Proteasome α Subunit Assembly Mechanism Mediated by the Proteasome-Assembling Chaperone PAC3-PAC4 Heterodimer
title_full Molecular and Structural Basis of the Proteasome α Subunit Assembly Mechanism Mediated by the Proteasome-Assembling Chaperone PAC3-PAC4 Heterodimer
title_fullStr Molecular and Structural Basis of the Proteasome α Subunit Assembly Mechanism Mediated by the Proteasome-Assembling Chaperone PAC3-PAC4 Heterodimer
title_full_unstemmed Molecular and Structural Basis of the Proteasome α Subunit Assembly Mechanism Mediated by the Proteasome-Assembling Chaperone PAC3-PAC4 Heterodimer
title_short Molecular and Structural Basis of the Proteasome α Subunit Assembly Mechanism Mediated by the Proteasome-Assembling Chaperone PAC3-PAC4 Heterodimer
title_sort molecular and structural basis of the proteasome α subunit assembly mechanism mediated by the proteasome-assembling chaperone pac3-pac4 heterodimer
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6539346/
https://www.ncbi.nlm.nih.gov/pubmed/31067643
http://dx.doi.org/10.3390/ijms20092231
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