Phorbol ester-dependent regulation of nuclear protein tyrosine phosphatase in situ.
Incubation of splenal lymphocytes with phorbol ester (50 nM PMA) influenced nuclear protein tyrosine phosphatase activity in a time-dependent manner. The activity was elevated after a short incubation (90 s) but was decreased in comparison to untreated cells after 30 and 120 min of incubation. The presence of H7 suppressed the changes. Okadaic acid, an inhibitor of protein phosphatases 2A and 1, led to a similar increase in the activity of nuclear protein tyrosine phosphatase during short-term incubations as phorbol ester but eliminated the subsequent activity decrease. Immunoblots revealed that the same amounts of two forms (49,000 and 60,000 M(r)) of protein tyrosine phosphatases were present in the nuclei from phorbol ester-stimulated and non-stimulated cells. The 60,000 M(r) form co-migrated with a phosphotyrosine-containing protein. The amount of phosphotyrosine was increased in comparison to control cells after 30 min of phorbol ester treatment.
Faculty of Biology, University of Konstanz, Germany.
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Heimerl
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Stader
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Willmann
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Hofer
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D002273:Carcinogens / Q000494:pharmacology*; D002467:Cell Nucleus / Q000187:drug effects / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004988:Ethers, Cyclic / Q000494:pharmacology; D015151:Immunoblotting; D007546:Isoquinolines / Q000494:pharmacology; D008214:Lymphocytes / Q000187:drug effects / Q000201:enzymology*; D008970:Molecular Weight; D009687:Nuclear Proteins / Q000378:metabolism; D019319:Okadaic Acid; D010766:Phosphorylation; D010879:Piperazines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D013154:Spleen / Q000166:cytology; D013552:Swine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013997:Time Factors
D002273:Carcinogens; D004791:Enzyme Inhibitors; D004988:Ethers, Cyclic; D007546:Isoquinolines; D009687:Nuclear Proteins; D010879:Piperazines; D019319:Okadaic Acid; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D017027:Protein Tyrosine Phosphatases; D013755:Tetradecanoylphorbol Acetate