Genotoxic stress-induced nuclear localization of oncoprotein YB-1 in the absence of proteolytic processing

S B Cohen; W Ma; V A Valova; M Algie; R Harfoot; A G Woolley; P J Robinson; A W Braithwaite

doi:10.1038/onc.2009.321

Genotoxic stress-induced nuclear localization of oncoprotein YB-1 in the absence of proteolytic processing

Oncogene. 2010 Jan 21;29(3):403-10. doi: 10.1038/onc.2009.321. Epub 2009 Oct 19.

Authors

S B Cohen¹, W Ma, V A Valova, M Algie, R Harfoot, A G Woolley, P J Robinson, A W Braithwaite

Affiliation

¹ Cell Transformation Unit, Children's Medical Research Institute, Westmead, New South Wales, 2145, Australia.

PMID: 19838214
DOI: 10.1038/onc.2009.321

Abstract

Y-box-binding protein 1 (YB-1) is an oncogenic transcription factor whose overexpression and nuclear localization is associated with tumor progression and drug resistance. Transcriptional activation of YB-1 in response to genotoxic stress is believed to occur in the cytoplasm through sequence-specific endoproteolytic cleavage by the 20S Proteasome, followed by nuclear translocation of cleaved YB-1. To study the proteolysis model, we developed a two-step affinity purification of endogenous YB-1 protein species and characterized the products using mass spectrometry. Whereas full-length YB-1 was readily identified, the smaller protein band thought to be activated YB-1 was identified as hnRNP A1. An antibody specific for YB-1 was generated, which revealed only one YB-1 species, even after genotoxic stress-induced nuclear YB-1 translocation. These findings warrant re-evaluation of the mechanism of YB-1 nuclear translocation and transcriptional activation. The relationship between nuclear YB-1 and tumor progression may also have to re-evaluated in some cases.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Active Transport, Cell Nucleus / drug effects
Active Transport, Cell Nucleus / radiation effects
Antineoplastic Agents / pharmacology
Blotting, Western
Cell Line, Tumor
Cell Nucleus / metabolism*
Chromatography, Liquid
Cisplatin / pharmacology
Cytoplasm / metabolism*
DNA Damage*
DNA-Binding Proteins / chemistry
DNA-Binding Proteins / genetics
DNA-Binding Proteins / metabolism*
Dactinomycin / pharmacology
Fluorescent Antibody Technique, Indirect
Humans
Nuclear Proteins / chemistry
Nuclear Proteins / genetics
Nuclear Proteins / metabolism*
Nucleic Acid Synthesis Inhibitors / pharmacology
Protein Transport / drug effects
Protein Transport / radiation effects
RNA Interference
Tandem Mass Spectrometry
Transcriptional Activation / drug effects
Transcriptional Activation / radiation effects
Ultraviolet Rays
Y-Box-Binding Protein 1

Substances

Antineoplastic Agents
DNA-Binding Proteins
Nuclear Proteins
Nucleic Acid Synthesis Inhibitors
Y-Box-Binding Protein 1
YBX1 protein, human
Dactinomycin
Cisplatin