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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
32
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pubmed:dateCreated |
1999-9-8
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pubmed:abstractText |
The cellular location and substrate specificity of the catalytic subunit (C) of protein phosphatase 2A (PP2A) depend on its interaction with A and B subunits. The distribution of epitope-tagged wild-type or mutated C subunits was studied by transient expression in COS-7 cells. Wild-type tagged C expressed at low levels formed ABC trimer and AC dimer like the endogenous C. Single mutations of C at the site of phosphorylation (Y307F) or carboxymethylation (L309Q) resulted in recovery of only AC dimer. Double mutation of both residues resulted in association of C with alpha 4 protein (alpha 4), a novel subunit of PP2A, instead of with A and B subunits. Thus, the distribution of C between ABC trimer, AC dimer, and alpha 4C complexes can be affected by modifications of the C-terminal residues. The alpha 4 protein is a homologue of the yeast Tap42 protein that functions downstream of the TOR protein to regulate protein synthesis. Transient overexpression of FLAG-alpha 4 resulted in increased dephosphorylation of elongation factor 2, but had no effect on phosphorylation of either p70S6 kinase or PHAS-I (eIF4E-BP). Signals that affect phosphorylation or methylation of the C subunit of PP2A may promote subunit exchange and direct phosphatase activity to specific intracellular substrates.
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pubmed:grant |
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Anion Exchange Resins,
http://linkedlifedata.com/resource/pubmed/chemical/Bacterial Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/FLAG peptide,
http://linkedlifedata.com/resource/pubmed/chemical/Hemagglutinins,
http://linkedlifedata.com/resource/pubmed/chemical/Lectins,
http://linkedlifedata.com/resource/pubmed/chemical/Leucine,
http://linkedlifedata.com/resource/pubmed/chemical/Mono Q,
http://linkedlifedata.com/resource/pubmed/chemical/Oligopeptides,
http://linkedlifedata.com/resource/pubmed/chemical/Peptide Elongation Factor 2,
http://linkedlifedata.com/resource/pubmed/chemical/Peptide Elongation Factors,
http://linkedlifedata.com/resource/pubmed/chemical/Peptides,
http://linkedlifedata.com/resource/pubmed/chemical/Phosphoprotein Phosphatases,
http://linkedlifedata.com/resource/pubmed/chemical/Phosphoproteins,
http://linkedlifedata.com/resource/pubmed/chemical/Protein Phosphatase 2,
http://linkedlifedata.com/resource/pubmed/chemical/Resins, Synthetic,
http://linkedlifedata.com/resource/pubmed/chemical/Tyrosine,
http://linkedlifedata.com/resource/pubmed/chemical/hemagglutinin A, Porphyromonas...
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pubmed:status |
MEDLINE
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pubmed:month |
Aug
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pubmed:issn |
0006-2960
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
10
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pubmed:volume |
38
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
10371-6
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pubmed:dateRevised |
2007-11-15
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pubmed:meshHeading |
pubmed-meshheading:10441131-Animals,
pubmed-meshheading:10441131-Anion Exchange Resins,
pubmed-meshheading:10441131-Bacterial Proteins,
pubmed-meshheading:10441131-COS Cells,
pubmed-meshheading:10441131-Catalytic Domain,
pubmed-meshheading:10441131-Chromatography, Ion Exchange,
pubmed-meshheading:10441131-Hemagglutinins,
pubmed-meshheading:10441131-Lectins,
pubmed-meshheading:10441131-Leucine,
pubmed-meshheading:10441131-Mutagenesis, Site-Directed,
pubmed-meshheading:10441131-Oligopeptides,
pubmed-meshheading:10441131-Peptide Elongation Factor 2,
pubmed-meshheading:10441131-Peptide Elongation Factors,
pubmed-meshheading:10441131-Peptides,
pubmed-meshheading:10441131-Phosphoprotein Phosphatases,
pubmed-meshheading:10441131-Phosphoproteins,
pubmed-meshheading:10441131-Phosphorylation,
pubmed-meshheading:10441131-Precipitin Tests,
pubmed-meshheading:10441131-Protein Phosphatase 2,
pubmed-meshheading:10441131-Resins, Synthetic,
pubmed-meshheading:10441131-Transfection,
pubmed-meshheading:10441131-Tyrosine
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pubmed:year |
1999
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pubmed:articleTitle |
Mutation of Tyr307 and Leu309 in the protein phosphatase 2A catalytic subunit favors association with the alpha 4 subunit which promotes dephosphorylation of elongation factor-2.
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pubmed:affiliation |
Center for Cell Signaling, The University of Virginia, Charlottesville 22908, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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