The α5-α6-α7-Pba3-Pba4 Complex: A Starting Unit in Proteasome Core Particle Assembly

A complex composed of Pba3-Pba4 and subunits α5, α6, and α7 is identified as an early intermediate in proteasome core particle assembly in wild-type <i>Saccharomyces cerevisiae</i> cell<i>s</i>. The same complex can be reconstituted from recombinantly produced components in v...

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Main Authors: Ana C. Matias, Margarida N. Tiago, Jessica Zimmermann, R. Jürgen Dohmen, Paula C. Ramos
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Biomolecules
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Online Access:https://www.mdpi.com/2218-273X/15/5/683
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author Ana C. Matias
Margarida N. Tiago
Jessica Zimmermann
R. Jürgen Dohmen
Paula C. Ramos
author_facet Ana C. Matias
Margarida N. Tiago
Jessica Zimmermann
R. Jürgen Dohmen
Paula C. Ramos
author_sort Ana C. Matias
collection DOAJ
description A complex composed of Pba3-Pba4 and subunits α5, α6, and α7 is identified as an early intermediate in proteasome core particle assembly in wild-type <i>Saccharomyces cerevisiae</i> cell<i>s</i>. The same complex can be reconstituted from recombinantly produced components in vitro. Assembly of α6 and α7 with Pba3-Pba4 depends on the presence of the α5 subunit, the binding of which apparently initiates the formation of this intermediate. Our data suggest the following order of events: first, Pba3-Pba4 binds α5, then α6 is incorporated, and at the end α7. In the absence of the chaperones Pba1-Pba2 or Ump1, alternative Pba4-containing complexes are detected, the formation of which depends on the Blm10/PA200 protein. Overexpression of Pba1-Pba2 abolishes the formation of these complexes containing Pba4 and Blm10, suggesting that Blm10 may replace Pba1-Pba2 as an alternative assembly factor.
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spelling doaj-art-4c7911df25d6445c8f9a3e44da10bc842025-08-20T03:14:45ZengMDPI AGBiomolecules2218-273X2025-05-0115568310.3390/biom15050683The α5-α6-α7-Pba3-Pba4 Complex: A Starting Unit in Proteasome Core Particle AssemblyAna C. Matias0Margarida N. Tiago1Jessica Zimmermann2R. Jürgen Dohmen3Paula C. Ramos4Center of Molecular Biosciences, Institute for Genetics, Department of Biology, Faculty of Natural Sciences and Mathematics, University of Cologne, 50674 Cologne, GermanyCenter of Molecular Biosciences, Institute for Genetics, Department of Biology, Faculty of Natural Sciences and Mathematics, University of Cologne, 50674 Cologne, GermanyCenter of Molecular Biosciences, Institute for Genetics, Department of Biology, Faculty of Natural Sciences and Mathematics, University of Cologne, 50674 Cologne, GermanyCenter of Molecular Biosciences, Institute for Genetics, Department of Biology, Faculty of Natural Sciences and Mathematics, University of Cologne, 50674 Cologne, GermanyCenter of Molecular Biosciences, Institute for Genetics, Department of Biology, Faculty of Natural Sciences and Mathematics, University of Cologne, 50674 Cologne, GermanyA complex composed of Pba3-Pba4 and subunits α5, α6, and α7 is identified as an early intermediate in proteasome core particle assembly in wild-type <i>Saccharomyces cerevisiae</i> cell<i>s</i>. The same complex can be reconstituted from recombinantly produced components in vitro. Assembly of α6 and α7 with Pba3-Pba4 depends on the presence of the α5 subunit, the binding of which apparently initiates the formation of this intermediate. Our data suggest the following order of events: first, Pba3-Pba4 binds α5, then α6 is incorporated, and at the end α7. In the absence of the chaperones Pba1-Pba2 or Ump1, alternative Pba4-containing complexes are detected, the formation of which depends on the Blm10/PA200 protein. Overexpression of Pba1-Pba2 abolishes the formation of these complexes containing Pba4 and Blm10, suggesting that Blm10 may replace Pba1-Pba2 as an alternative assembly factor.https://www.mdpi.com/2218-273X/15/5/683proteasome core particleassemblychaperonesPba3-Pba4Blm10
spellingShingle Ana C. Matias
Margarida N. Tiago
Jessica Zimmermann
R. Jürgen Dohmen
Paula C. Ramos
The α5-α6-α7-Pba3-Pba4 Complex: A Starting Unit in Proteasome Core Particle Assembly
Biomolecules
proteasome core particle
assembly
chaperones
Pba3-Pba4
Blm10
title The α5-α6-α7-Pba3-Pba4 Complex: A Starting Unit in Proteasome Core Particle Assembly
title_full The α5-α6-α7-Pba3-Pba4 Complex: A Starting Unit in Proteasome Core Particle Assembly
title_fullStr The α5-α6-α7-Pba3-Pba4 Complex: A Starting Unit in Proteasome Core Particle Assembly
title_full_unstemmed The α5-α6-α7-Pba3-Pba4 Complex: A Starting Unit in Proteasome Core Particle Assembly
title_short The α5-α6-α7-Pba3-Pba4 Complex: A Starting Unit in Proteasome Core Particle Assembly
title_sort α5 α6 α7 pba3 pba4 complex a starting unit in proteasome core particle assembly
topic proteasome core particle
assembly
chaperones
Pba3-Pba4
Blm10
url https://www.mdpi.com/2218-273X/15/5/683
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