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Title: Recruitment of phosphorylated small heat shock protein Hsp27 to nuclear speckles without stress

Abstract

During stress, the mammalian small heat shock protein Hsp27 enters cell nuclei. The present study examines the requirements for entry of Hsp27 into nuclei of normal rat kidney (NRK) renal epithelial cells, and for its interactions with specific nuclear structures. We find that phosphorylation of Hsp27 is necessary for the efficient entry into nuclei during heat shock but not sufficient for efficient nuclear entry under control conditions. We further report that Hsp27 is recruited to an RNAse sensitive fraction of SC35 positive nuclear speckles, but not other intranuclear structures, in response to heat shock. Intriguingly, Hsp27 phosphorylation, in the absence of stress, is sufficient for recruitment to speckles found in post-anaphase stage mitotic cells. Additionally, pseudophosphorylated Hsp27 fused to a nuclear localization peptide (NLS) is recruited to nuclear speckles in unstressed interphase cells, but wildtype and nonphosphorylatable Hsp27 NLS fusion proteins are not. The expression of NLS-Hsp27 mutants does not enhance colony forming abilities of cells subjected to severe heat shock, but does regulate nuclear speckle morphology. These data demonstrate that phosphorylation, but not stress, mediates Hsp27 recruitment to an RNAse soluble fraction of nuclear speckles and support a site-specific role for Hsp27 within the nucleus.

Authors:
 [1];  [1];  [2]
  1. School of Molecular Biosciences, Washington State University, Pullman, WA (United States)
  2. School of Molecular Biosciences, Washington State University, Pullman, WA (United States) and Center for Reproductive Biology, Washington State University, Pullman, WA (United States). E-mail: eshelden@wsu.edu
Publication Date:
OSTI Identifier:
20858071
Resource Type:
Journal Article
Resource Relation:
Journal Name: Experimental Cell Research; Journal Volume: 313; Journal Issue: 1; Other Information: DOI: 10.1016/j.yexcr.2006.10.004; PII: S0014-4827(06)00422-8; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; BIOLOGICAL STRESS; CELL NUCLEI; HEAT-SHOCK PROTEINS; KIDNEYS; MITOSIS; MORPHOLOGY; MUTANTS; NUCLEAR STRUCTURE; PEPTIDES; PHOSPHORYLATION; RATS

Citation Formats

Bryantsev, A.L., Chechenova, M.B., and Shelden, E.A. Recruitment of phosphorylated small heat shock protein Hsp27 to nuclear speckles without stress. United States: N. p., 2007. Web. doi:10.1016/j.yexcr.2006.10.004.
Bryantsev, A.L., Chechenova, M.B., & Shelden, E.A. Recruitment of phosphorylated small heat shock protein Hsp27 to nuclear speckles without stress. United States. doi:10.1016/j.yexcr.2006.10.004.
Bryantsev, A.L., Chechenova, M.B., and Shelden, E.A. Mon . "Recruitment of phosphorylated small heat shock protein Hsp27 to nuclear speckles without stress". United States. doi:10.1016/j.yexcr.2006.10.004.
@article{osti_20858071,
title = {Recruitment of phosphorylated small heat shock protein Hsp27 to nuclear speckles without stress},
author = {Bryantsev, A.L. and Chechenova, M.B. and Shelden, E.A.},
abstractNote = {During stress, the mammalian small heat shock protein Hsp27 enters cell nuclei. The present study examines the requirements for entry of Hsp27 into nuclei of normal rat kidney (NRK) renal epithelial cells, and for its interactions with specific nuclear structures. We find that phosphorylation of Hsp27 is necessary for the efficient entry into nuclei during heat shock but not sufficient for efficient nuclear entry under control conditions. We further report that Hsp27 is recruited to an RNAse sensitive fraction of SC35 positive nuclear speckles, but not other intranuclear structures, in response to heat shock. Intriguingly, Hsp27 phosphorylation, in the absence of stress, is sufficient for recruitment to speckles found in post-anaphase stage mitotic cells. Additionally, pseudophosphorylated Hsp27 fused to a nuclear localization peptide (NLS) is recruited to nuclear speckles in unstressed interphase cells, but wildtype and nonphosphorylatable Hsp27 NLS fusion proteins are not. The expression of NLS-Hsp27 mutants does not enhance colony forming abilities of cells subjected to severe heat shock, but does regulate nuclear speckle morphology. These data demonstrate that phosphorylation, but not stress, mediates Hsp27 recruitment to an RNAse soluble fraction of nuclear speckles and support a site-specific role for Hsp27 within the nucleus.},
doi = {10.1016/j.yexcr.2006.10.004},
journal = {Experimental Cell Research},
number = 1,
volume = 313,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}