Cargando…
The penultimate step of proteasomal ATPase assembly is mediated by a switch dependent on the chaperone Nas2
The proteasome holoenzyme is a complex molecular machine that degrades most proteins. In the proteasome holoenzyme, six distinct ATPase subunits (Rpt1 through Rpt6) enable protein degradation by injecting protein substrates into it. Individual Rpt subunits assemble into a heterohexameric “Rpt ring”...
Autores principales: | , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Society for Biochemistry and Molecular Biology
2023
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9922823/ https://www.ncbi.nlm.nih.gov/pubmed/36621624 http://dx.doi.org/10.1016/j.jbc.2023.102870 |
_version_ | 1784887611170488320 |
---|---|
author | Sekaran, Suganya Park, Soyeon |
author_facet | Sekaran, Suganya Park, Soyeon |
author_sort | Sekaran, Suganya |
collection | PubMed |
description | The proteasome holoenzyme is a complex molecular machine that degrades most proteins. In the proteasome holoenzyme, six distinct ATPase subunits (Rpt1 through Rpt6) enable protein degradation by injecting protein substrates into it. Individual Rpt subunits assemble into a heterohexameric “Rpt ring” in a stepwise manner, by binding to their cognate chaperones. Completion of the heterohexameric Rpt ring correlates with release of a specific chaperone, Nas2; however, it is unclear whether and how this event may ensure proper Rpt ring assembly. Here, we examined the action of Nas2 by capturing the poorly characterized penultimate step of heterohexameric Rpt ring assembly. For this, we used a heterologous Escherichia coli system coexpressing all Rpt subunits and assembly chaperones as well as Saccharomyces cerevisiae to track Nas2 actions during endogenous Rpt ring assembly. We show that Nas2 uses steric hindrance to block premature progression of the penultimate step into the final step of Rpt ring assembly. Importantly, Nas2 can activate an assembly checkpoint via its steric activity, when the last ATPase subunit, Rpt1, cannot be added in a timely manner. This checkpoint can be relieved via Nas2 release, when Nas2 recognizes proper addition of Rpt1 to one side of its cognate Rpt5, and ATP hydrolysis by Rpt4 on the other side of Rpt5, allowing completion of Rpt ring assembly. Our findings reveal dual criteria for Nas2 release, as a mechanism to ensure both the composition and functional competence of a newly assembled proteasomal ATPase, to generate the proteasome holoenzyme. |
format | Online Article Text |
id | pubmed-9922823 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | American Society for Biochemistry and Molecular Biology |
record_format | MEDLINE/PubMed |
spelling | pubmed-99228232023-02-14 The penultimate step of proteasomal ATPase assembly is mediated by a switch dependent on the chaperone Nas2 Sekaran, Suganya Park, Soyeon J Biol Chem Research Article The proteasome holoenzyme is a complex molecular machine that degrades most proteins. In the proteasome holoenzyme, six distinct ATPase subunits (Rpt1 through Rpt6) enable protein degradation by injecting protein substrates into it. Individual Rpt subunits assemble into a heterohexameric “Rpt ring” in a stepwise manner, by binding to their cognate chaperones. Completion of the heterohexameric Rpt ring correlates with release of a specific chaperone, Nas2; however, it is unclear whether and how this event may ensure proper Rpt ring assembly. Here, we examined the action of Nas2 by capturing the poorly characterized penultimate step of heterohexameric Rpt ring assembly. For this, we used a heterologous Escherichia coli system coexpressing all Rpt subunits and assembly chaperones as well as Saccharomyces cerevisiae to track Nas2 actions during endogenous Rpt ring assembly. We show that Nas2 uses steric hindrance to block premature progression of the penultimate step into the final step of Rpt ring assembly. Importantly, Nas2 can activate an assembly checkpoint via its steric activity, when the last ATPase subunit, Rpt1, cannot be added in a timely manner. This checkpoint can be relieved via Nas2 release, when Nas2 recognizes proper addition of Rpt1 to one side of its cognate Rpt5, and ATP hydrolysis by Rpt4 on the other side of Rpt5, allowing completion of Rpt ring assembly. Our findings reveal dual criteria for Nas2 release, as a mechanism to ensure both the composition and functional competence of a newly assembled proteasomal ATPase, to generate the proteasome holoenzyme. American Society for Biochemistry and Molecular Biology 2023-01-05 /pmc/articles/PMC9922823/ /pubmed/36621624 http://dx.doi.org/10.1016/j.jbc.2023.102870 Text en © 2023 The Authors https://creativecommons.org/licenses/by/4.0/This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Research Article Sekaran, Suganya Park, Soyeon The penultimate step of proteasomal ATPase assembly is mediated by a switch dependent on the chaperone Nas2 |
title | The penultimate step of proteasomal ATPase assembly is mediated by a switch dependent on the chaperone Nas2 |
title_full | The penultimate step of proteasomal ATPase assembly is mediated by a switch dependent on the chaperone Nas2 |
title_fullStr | The penultimate step of proteasomal ATPase assembly is mediated by a switch dependent on the chaperone Nas2 |
title_full_unstemmed | The penultimate step of proteasomal ATPase assembly is mediated by a switch dependent on the chaperone Nas2 |
title_short | The penultimate step of proteasomal ATPase assembly is mediated by a switch dependent on the chaperone Nas2 |
title_sort | penultimate step of proteasomal atpase assembly is mediated by a switch dependent on the chaperone nas2 |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9922823/ https://www.ncbi.nlm.nih.gov/pubmed/36621624 http://dx.doi.org/10.1016/j.jbc.2023.102870 |
work_keys_str_mv | AT sekaransuganya thepenultimatestepofproteasomalatpaseassemblyismediatedbyaswitchdependentonthechaperonenas2 AT parksoyeon thepenultimatestepofproteasomalatpaseassemblyismediatedbyaswitchdependentonthechaperonenas2 AT sekaransuganya penultimatestepofproteasomalatpaseassemblyismediatedbyaswitchdependentonthechaperonenas2 AT parksoyeon penultimatestepofproteasomalatpaseassemblyismediatedbyaswitchdependentonthechaperonenas2 |