Universität zu Köln

Zimmermann, Jessica, Ramos, Paula C. and Dohmen, R. Juergen (2022). Interaction with the Assembly Chaperone Ump1 Promotes Incorporation of the beta 7 Subunit into Half-Proteasome Precursor Complexes Driving Their Dimerization. Biomolecules, 12 (2). BASEL: MDPI. ISSN 2218-273X

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Abstract

Biogenesis of the eukaryotic 20S proteasome core particle (PC) is a complex process assisted by specific chaperones absent from the active complex. The first identified chaperone, Ump1, was found in a precursor complex (PC) called 15S PC. Yeast cells lacking Ump1 display strong defects in the autocatalytic processing of beta subunits, and consequently have lower proteolytic activity. Here, we dissect an important interaction of Ump1 with the beta 7 subunit that is critical for proteasome biogenesis. Functional domains of Ump1 and the interacting proteasome subunit beta 7 were mapped, and the functional consequences of their deletion or mutation were analyzed. Cells in which the first sixteen Ump1 residues were deleted display growth phenotypes similar to ump1 increment , but massively accumulate 15S PC and distinct proteasome intermediate complexes containing the truncated protein. The viability of these cells depends on the transcription factor Rpn4. Remarkably, beta 7 subunit overexpression re-established viability in the absence of Rpn4. We show that an N-terminal domain of Ump1 and the propeptide of beta 7 promote direct interaction of the two polypeptides in vitro. This interaction is of critical importance for the recruitment of beta 7 precursor during proteasome assembly, a step that drives dimerization of 15S PCs and the formation of 20S CPs.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Zimmermann, Jessica UNSPECIFIED UNSPECIFIED UNSPECIFIED Ramos, Paula C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Dohmen, R. Juergen UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-657066
DOI:	10.3390/biom12020253
Journal or Publication Title:	Biomolecules
Volume:	12
Number:	2
Date:	2022
Publisher:	MDPI
Place of Publication:	BASEL
ISSN:	2218-273X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language 20S PROTEASOME; SHUTTLE VECTORS; YEAST; MATURATION; MUTATIONS; SUBSTRATE; UBIQUITIN; SYSTEM; RPN4; DNA Multiple languages Biochemistry & Molecular Biology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/65706