Structural roles of Ump1 and ß-subunit propeptides in proteasome biogenesis.
Life Sci Alliance
; 7(11)2024 Nov.
Article
em En
| MEDLINE
| ID: mdl-39260885
ABSTRACT
The yeast pre1-1(ß4-S142F) mutant accumulates late 20S proteasome core particle precursor complexes (late-PCs). We report a 2.1 Å cryo-EM structure of this intermediate with full-length Ump1 trapped inside, and Pba1-Pba2 attached to the α-ring surfaces. The structure discloses intimate interactions of Ump1 with ß2- and ß5-propeptides, which together fill most of the antechambers between the α- and ß-rings. The ß5-propeptide is unprocessed and separates Ump1 from ß6 and ß7. The ß2-propeptide is disconnected from the subunit by autocatalytic processing and localizes between Ump1 and ß3. A comparison of different proteasome maturation states reveals that maturation goes along with global conformational changes in the rings, initiated by structuring of the proteolytic sites and their autocatalytic activation. In the pre1-1 strain, ß2 is activated first enabling processing of ß1-, ß6-, and ß7-propeptides. Subsequent maturation of ß5 and ß1 precedes degradation of Ump1, tightening of the complex, and finally release of Pba1-Pba2.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Saccharomyces cerevisiae
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Microscopia Crioeletrônica
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Proteínas de Saccharomyces cerevisiae
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Complexo de Endopeptidases do Proteassoma
Idioma:
En
Revista:
Life Sci Alliance
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
Alemanha
País de publicação:
Estados Unidos