TY - JOUR
T1 - Proteasome assembly from 15S precursors involves major conformational changes and recycling of the Pba1-Pba2 chaperone
AU - Kock, Malte
AU - Nunes, Maria M.
AU - Hemann, Matthias
AU - Kube, Sebastian
AU - Jürgen Dohmen, R.
AU - Herzog, Franz
AU - Ramos, Paula C.
AU - Wendler, Petra
N1 - Funding Information:
We thank Cordula Enenkel for providing plasmid YIp5 Ump1-GFP-HA-TEV-ProA and strain BMF1, Stephanie Schwab for the antiserum against b5, Filipa Pardelha for plasmid pFP2 and Thomas Fröhlich for peptide mass fingerprinting analysis. We are grateful to Michael Groll for his help in initiating this collaborative project. F.H. and colleagues are supported by the Bavarian Research Center for Molecular Biosystems, the Graduate School 1721 (DFG) and by an LMUexcellent Junior grant. M.M.N. was supported by a pre-doctoral fellowship from the Portuguese Science Foundation (FCT) and P.C.R. by a re-entry grant from the University of Cologne. P.W. and colleagues are supported by an Emmy Noether grant of the German Research Council (WE 4628/1) and the Graduate School 1721 (DFG).
Publisher Copyright:
© 2015 Macmillan Publishers Limited. All rights reserved.
PY - 2015/1/22
Y1 - 2015/1/22
N2 - The chaperones Ump1 and Pba1-Pba2 promote efficient biogenesis of 20S proteasome core particles from its subunits via 15S intermediates containing alpha and beta subunits, except beta7. Here we elucidate the structural role of these chaperones in late steps of core particle biogenesis using biochemical, electron microscopy, cross-linking and mass spectrometry analyses. In 15S precursor complexes, Ump1 is largely unstructured, lining the inner cavity of the complex along the interface between alpha and beta subunits. The alpha and beta subunits form loosely packed rings with a wider alpha ring opening than in the 20S core particle, allowing for the Pba1-Pba2 heterodimer to be partially embedded in the central alpha ring cavity. During biogenesis, the heterodimer is expelled from the alpha ring by a restructuring event that organizes the beta ring and leads to tightening of the alpha ring opening. In this way, the Pba1-Pba2 chaperone is recycled for a new round of proteasome assembly.
AB - The chaperones Ump1 and Pba1-Pba2 promote efficient biogenesis of 20S proteasome core particles from its subunits via 15S intermediates containing alpha and beta subunits, except beta7. Here we elucidate the structural role of these chaperones in late steps of core particle biogenesis using biochemical, electron microscopy, cross-linking and mass spectrometry analyses. In 15S precursor complexes, Ump1 is largely unstructured, lining the inner cavity of the complex along the interface between alpha and beta subunits. The alpha and beta subunits form loosely packed rings with a wider alpha ring opening than in the 20S core particle, allowing for the Pba1-Pba2 heterodimer to be partially embedded in the central alpha ring cavity. During biogenesis, the heterodimer is expelled from the alpha ring by a restructuring event that organizes the beta ring and leads to tightening of the alpha ring opening. In this way, the Pba1-Pba2 chaperone is recycled for a new round of proteasome assembly.
KW - Cross-Linking Reagents/chemistry
KW - Dimerization
KW - Mass Spectrometry
KW - Microscopy, Electron
KW - Molecular Chaperones/metabolism
KW - Proteasome Endopeptidase Complex/chemistry
KW - Protein Binding
KW - Protein Conformation
KW - Protein Structure, Secondary
KW - Protein Structure, Tertiary
KW - Protein Subunits/metabolism
KW - Saccharomyces cerevisiae Proteins/metabolism
KW - Saccharomyces cerevisiae/metabolism
UR - http://www.scopus.com/inward/record.url?scp=84941012942&partnerID=8YFLogxK
U2 - 10.1038/ncomms7123
DO - 10.1038/ncomms7123
M3 - Article
C2 - 25609009
AN - SCOPUS:84941012942
SN - 2041-1723
VL - 6
SP - 6123
JO - Nature Communications
JF - Nature Communications
M1 - 6123
ER -
