Differential methylation and altered conformation of cytoplasmic and nuclear forms of protein phosphatase 2A during cell cycle progression.

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State: Public
Version: Final published version
License: Not specified
Serval ID
serval:BIB_8BFE9F59F2B8
Type
Article: article from journal or magazin.
Collection
Publications
Title
Differential methylation and altered conformation of cytoplasmic and nuclear forms of protein phosphatase 2A during cell cycle progression.
Journal
The Journal of cell biology
Author(s)
Turowski P., Fernandez A., Favre B., Lamb N.J., Hemmings B.A.
ISSN
0021-9525 (Print)
ISSN-L
0021-9525
Publication state
Published
Issued date
04/1995
Peer-reviewed
Oui
Volume
129
Number
2
Pages
397-410
Language
english
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Abstract
Protein phosphatase 2A (PP2A) appears to be involved in the regulation of many cellular processes. Control mechanisms that lead to the activation (and deactivation) of the various holoenzymes to initiate appropriate dephosphorylation events remain obscure. The core components of all PP2A holoenzymes are the catalytic (PP2Ac) and 63-65-kD regulatory (PR65) subunits. Monospecific and affinity-purified antibodies against both PP2Ac and PR65 show that these proteins are ubiquitously localized in the cytoplasm and the nucleus in nontransformed fibroblasts. As determined by quantitative immunofluorescence the core subunits of PP2A are twofold more concentrated in the nucleus than in the cytoplasm. Detailed analysis of synchronized cells reveals striking changes in the nuclear to cytoplasmic ratio of PP2Ac-specific immunoreactivity albeit the total amounts of neither PP2Ac nor PR65 in each compartment alters significantly during the cell cycle. Our results imply that differential methylation of PP2Ac occurs at the G0/G1 and G1/S boundaries. Specifically a demethylated form of PP2Ac is found in the cytoplasm of G1 cells, and in the nucleus of S and G2 cells. In addition nuclear PP2A holoenzymes appear to undergo conformational changes at the G0/G1 and G1/S boundaries. During mitosis PP2A is lost from the nuclear compartment, and unlike protein phosphatase 1 shows no specific association with the condensed chromatin.
Keywords
Amino Acid Sequence, Animals, Cell Nucleus/enzymology, Chromatin/chemistry, Cytoplasm/enzymology, Enzyme Activation, Humans, Interphase, Methylation, Mitosis, Molecular Sequence Data, Peptides/chemical synthesis, Peptides/immunology, Phosphoprotein Phosphatases/analysis, Phosphoprotein Phosphatases/chemistry, Phosphoprotein Phosphatases/metabolism, Protein Conformation, Protein Phosphatase 1, Protein Phosphatase 2, Rats, Recombinant Proteins/immunology, Recombinant Proteins/isolation & purification
Pubmed
Web of science
Open Access
Yes
Create date
25/01/2008 17:32
Last modification date
09/08/2024 13:52
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