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The C-terminal extension of the beta 7 subunit and activator complexes stabilize nascent 20 S proteasomes and promote their maturation

dc.contributor.authorMarques, Antonio J.
dc.contributor.authorGlanemann, Christoph
dc.contributor.authorRamos, Paula C.
dc.contributor.authorDohmen, Juergen
dc.date.accessioned2018-12-07T14:58:00Z
dc.date.available2018-12-07T14:58:00Z
dc.date.issued2007-11
dc.description.abstractThe eukaryotic 20 S proteasome is formed by dimerization of two precursor complexes containing the maturation factor Ump1. beta 7/Pre4 is the only one of the 14 subunits forming the 20 S proteasome that is absent from these precursor complexes in Saccharomyces cerevisiae. Increased expression of Pre4 leads to a reduction in the level of precursor complex, indicating that Pre4 incorporation into these complexes is rate-limiting for their dimerization. When we purified these precursor complexes, we observed co-purification of Blm10, a large protein known to attach to the alpha ring surface of proteasomes. In contrast to single mutants lacking either Blm10 or the C-terminal extension of Pre4, a mutant lacking both grew extremely poorly, accumulated very high levels of precursor complexes, and was impaired in beta subunit maturation. The effect of blm10 Delta on proteasome biogenesis is modest, apparently because the 19 S regulatory particle is capable of substituting for Blm10, as long as precursor complex dimers are stabilized by the Pre4Cterminus. We found that a mutation (sen3/rpn2) affecting the Rpn2 subunit inhibits attachment of the 19 S activator to the 20 S particle or its precursors. Although the sen3 mutation alone had no apparent effect on precursor complex dimerization and active site maturation, the sen3 blm10 double mutant was impaired in these processes. Together these data demonstrate that Blm10 and the 19 S activator have a partially redundant function in stabilizing nascent 20 S proteasomes and in promoting their activation.
dc.description.versioninfo:eu-repo/semantics/publishedVersion
dc.identifier.doi10.1074/jbc.M705836200
dc.identifier.issn0021-9258
dc.identifier.urihttp://hdl.handle.net/10400.1/11809
dc.language.isoeng
dc.peerreviewedyes
dc.publisherAmer Soc Biochemistry Molecular Biology Inc
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/
dc.subject26S Proteasome
dc.subjectSite formation
dc.subjectYeast
dc.subjectUbiquitin
dc.subjectDegradation
dc.subjectCompletion
dc.subjectBiogenesis
dc.subjectChaperones
dc.subjectExpression
dc.subjectResolution
dc.titleThe C-terminal extension of the beta 7 subunit and activator complexes stabilize nascent 20 S proteasomes and promote their maturation
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage34876
oaire.citation.issue48
oaire.citation.startPage34869
oaire.citation.titleJournal of Biological Chemistry
oaire.citation.volume282
rcaap.rightsopenAccess
rcaap.typearticle

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