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

Details

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
Journal of Cell Biology
Author(s)
Turowski  P., Fernandez  A., Favre  B., Lamb  N. J., Hemmings  B. A.
ISSN
0021-9525 (Print)
Publication state
Published
Issued date
04/1995
Volume
129
Number
2
Pages
397-410
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Apr
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/immunology Phosphoprotein Phosphatase/analysis/*chemistry/metabolism *Protein Conformation Rats Recombinant Proteins/immunology/isolation & purification
Pubmed
Web of science
Open Access
Yes
Create date
25/01/2008 17:32
Last modification date
20/08/2019 15:50
Usage data