Proteomic Characterization of Aggregating Proteins after the Inhibition of the Ubiquitin Proteasome System

Protein aggregation, which is associated with the impairment of the ubiquitin proteasome system, is a hallmark of many neurodegenerative diseases. To better understand the contribution of proteasome inhibition in aggregation, we analyzed which proteins may potentially localize in chemically induced...

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Bibliographic Details
Published in:	Journal of proteome research Vol. 10; no. 3; pp. 1062 - 1072
Main Authors:	Wilde, Inga B, Brack, Maria, Winget, Jason M, Mayor, Thibault
Format:	Journal Article
Language:	English
Published:	United States American Chemical Society 04-03-2011
Subjects:	Amino Acid Sequence Cell Line, Tumor Humans Mass Spectrometry - methods Molecular Sequence Data Neuroblastoma - metabolism Proteasome Endopeptidase Complex - metabolism Proteasome Inhibitors Proteins - chemistry Proteins - genetics Proteins - metabolism Proteome - analysis Proteomics - methods Ubiquitin - metabolism proteasome aggregation neurodegenerative disease proteomics ubiquitin
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Summary:	Protein aggregation, which is associated with the impairment of the ubiquitin proteasome system, is a hallmark of many neurodegenerative diseases. To better understand the contribution of proteasome inhibition in aggregation, we analyzed which proteins may potentially localize in chemically induced aggregates in human neuroblastoma tissue culture cells. We enriched for proteins in high-density structures by using a sucrose gradient in combination with stable isotope labeling with amino acids in cell culture (SILAC). The quantitative analysis allowed us to distinguish which proteins were specifically affected by the proteasome inhibition. We identified 642 potentially aggregating proteins, including the p62/sequestosome 1 and NBR1 ubiquitin-binding proteins involved in aggregation. We also identified the ubiquitin-associated protein 2 like (UBAP2L). We verified that it cofractionated with ubiquitin in the high-density fraction and that it was colocalized in the ubiquitin-containing aggregates after proteasome inhibition. In addition, we identified several chaperone proteins and used data from protein interaction networks to show that they potentially interact with distinct subgroups of proteins within the aggregating structures. Several other proteins associated with neurodegenerative diseases, like UCHL1, were identified, further underlining the potential of our analysis to better understand the aggregation process and proteotoxic stress caused by proteasome inhibition.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	1535-3893 1535-3907
DOI:	10.1021/pr1008543