Accumulation of soluble and nucleolar-associated p53 proteins following cellular stress

Sergey A. Klibanov, Heather O'Hagan, Mats Ljungman

Research output: Contribution to journalArticle

69 Citations (Scopus)

Abstract

The tumor suppressor p53 is a nucleocytoplasmic shuttling protein that accumulates in the nucleus of cells exposed to various cellular stresses. One important role of nuclear p53 is to mobilize a stress response by transactivating target genes such as the p21Waf1 gene. In this study, we investigated more closely the localization of p53 in cells following various stresses. Immunocytochemistry of fixed human fibroblasts treated with either UV light, the kinase and transcription inhibitor DRB or the proteasome inhibitor MG132 revealed abundant p53 localized to the nucleus. When cells treated with UV or DRB were permeabilized prior to fixation to allow soluble proteins to diffuse, the nuclear p53 signal was abolished. However, in cells treated with MG132, residual p53 localized to distinct large foci. Furthermore, nucleolin co-localized with p53 to these foci, suggesting that these foci were nucleolar structures. Interestingly, the MDM2 protein was found to co-localize with p53 to nucleolar structures following proteasome inhibition. Our results suggest that the p53 proteins accumulating in the nucleus following UV-irradiation or blockage of transcription are freely soluble and, thus, should be able to roam the nucleus to ensure high occupancy of p53 binding sites. However, inhibition of proteasome activity may be a unique stress in that it leads to the sequestering of p53 proteins to the nucleolus, thereby blunting the p53-mediated transactivation of target genes.

Original languageEnglish (US)
Pages (from-to)1867-1873
Number of pages7
JournalJournal of Cell Science
Volume114
Issue number10
StatePublished - 2001
Externally publishedYes

Fingerprint

Dichlororibofuranosylbenzimidazole
Proteasome Endopeptidase Complex
Proteins
Genes
Proteasome Inhibitors
Ultraviolet Rays
Cell Nucleus
Transcriptional Activation
Phosphotransferases
Fibroblasts
Immunohistochemistry
Binding Sites
Neoplasms
benzyloxycarbonylleucyl-leucyl-leucine aldehyde
nucleolin

Keywords

  • MDM2
  • Proteasome inhibitors
  • Transcription Nucleolus
  • UV light

ASJC Scopus subject areas

  • Cell Biology

Cite this

Accumulation of soluble and nucleolar-associated p53 proteins following cellular stress. / Klibanov, Sergey A.; O'Hagan, Heather; Ljungman, Mats.

In: Journal of Cell Science, Vol. 114, No. 10, 2001, p. 1867-1873.

Research output: Contribution to journalArticle

Klibanov, Sergey A. ; O'Hagan, Heather ; Ljungman, Mats. / Accumulation of soluble and nucleolar-associated p53 proteins following cellular stress. In: Journal of Cell Science. 2001 ; Vol. 114, No. 10. pp. 1867-1873.
@article{50262c9013ee4ae2b55731eaa87e81ca,
title = "Accumulation of soluble and nucleolar-associated p53 proteins following cellular stress",
abstract = "The tumor suppressor p53 is a nucleocytoplasmic shuttling protein that accumulates in the nucleus of cells exposed to various cellular stresses. One important role of nuclear p53 is to mobilize a stress response by transactivating target genes such as the p21Waf1 gene. In this study, we investigated more closely the localization of p53 in cells following various stresses. Immunocytochemistry of fixed human fibroblasts treated with either UV light, the kinase and transcription inhibitor DRB or the proteasome inhibitor MG132 revealed abundant p53 localized to the nucleus. When cells treated with UV or DRB were permeabilized prior to fixation to allow soluble proteins to diffuse, the nuclear p53 signal was abolished. However, in cells treated with MG132, residual p53 localized to distinct large foci. Furthermore, nucleolin co-localized with p53 to these foci, suggesting that these foci were nucleolar structures. Interestingly, the MDM2 protein was found to co-localize with p53 to nucleolar structures following proteasome inhibition. Our results suggest that the p53 proteins accumulating in the nucleus following UV-irradiation or blockage of transcription are freely soluble and, thus, should be able to roam the nucleus to ensure high occupancy of p53 binding sites. However, inhibition of proteasome activity may be a unique stress in that it leads to the sequestering of p53 proteins to the nucleolus, thereby blunting the p53-mediated transactivation of target genes.",
keywords = "MDM2, Proteasome inhibitors, Transcription Nucleolus, UV light",
author = "Klibanov, {Sergey A.} and Heather O'Hagan and Mats Ljungman",
year = "2001",
language = "English (US)",
volume = "114",
pages = "1867--1873",
journal = "Journal of Cell Science",
issn = "0021-9533",
publisher = "Company of Biologists Ltd",
number = "10",

}

TY - JOUR

T1 - Accumulation of soluble and nucleolar-associated p53 proteins following cellular stress

AU - Klibanov, Sergey A.

AU - O'Hagan, Heather

AU - Ljungman, Mats

PY - 2001

Y1 - 2001

N2 - The tumor suppressor p53 is a nucleocytoplasmic shuttling protein that accumulates in the nucleus of cells exposed to various cellular stresses. One important role of nuclear p53 is to mobilize a stress response by transactivating target genes such as the p21Waf1 gene. In this study, we investigated more closely the localization of p53 in cells following various stresses. Immunocytochemistry of fixed human fibroblasts treated with either UV light, the kinase and transcription inhibitor DRB or the proteasome inhibitor MG132 revealed abundant p53 localized to the nucleus. When cells treated with UV or DRB were permeabilized prior to fixation to allow soluble proteins to diffuse, the nuclear p53 signal was abolished. However, in cells treated with MG132, residual p53 localized to distinct large foci. Furthermore, nucleolin co-localized with p53 to these foci, suggesting that these foci were nucleolar structures. Interestingly, the MDM2 protein was found to co-localize with p53 to nucleolar structures following proteasome inhibition. Our results suggest that the p53 proteins accumulating in the nucleus following UV-irradiation or blockage of transcription are freely soluble and, thus, should be able to roam the nucleus to ensure high occupancy of p53 binding sites. However, inhibition of proteasome activity may be a unique stress in that it leads to the sequestering of p53 proteins to the nucleolus, thereby blunting the p53-mediated transactivation of target genes.

AB - The tumor suppressor p53 is a nucleocytoplasmic shuttling protein that accumulates in the nucleus of cells exposed to various cellular stresses. One important role of nuclear p53 is to mobilize a stress response by transactivating target genes such as the p21Waf1 gene. In this study, we investigated more closely the localization of p53 in cells following various stresses. Immunocytochemistry of fixed human fibroblasts treated with either UV light, the kinase and transcription inhibitor DRB or the proteasome inhibitor MG132 revealed abundant p53 localized to the nucleus. When cells treated with UV or DRB were permeabilized prior to fixation to allow soluble proteins to diffuse, the nuclear p53 signal was abolished. However, in cells treated with MG132, residual p53 localized to distinct large foci. Furthermore, nucleolin co-localized with p53 to these foci, suggesting that these foci were nucleolar structures. Interestingly, the MDM2 protein was found to co-localize with p53 to nucleolar structures following proteasome inhibition. Our results suggest that the p53 proteins accumulating in the nucleus following UV-irradiation or blockage of transcription are freely soluble and, thus, should be able to roam the nucleus to ensure high occupancy of p53 binding sites. However, inhibition of proteasome activity may be a unique stress in that it leads to the sequestering of p53 proteins to the nucleolus, thereby blunting the p53-mediated transactivation of target genes.

KW - MDM2

KW - Proteasome inhibitors

KW - Transcription Nucleolus

KW - UV light

UR - http://www.scopus.com/inward/record.url?scp=0034993222&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034993222&partnerID=8YFLogxK

M3 - Article

C2 - 11329373

AN - SCOPUS:0034993222

VL - 114

SP - 1867

EP - 1873

JO - Journal of Cell Science

JF - Journal of Cell Science

SN - 0021-9533

IS - 10

ER -