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Inhibitors of phosphoprotein phosphatases 1 and 2A cause activation of a 53 kDa protein kinase accompanying the apoptotic response of breast cancer cells
Author(s) -
Rossini Gian Paolo,
Pinna Cristina,
Viviani Romano
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00659-5
Subject(s) - okadaic acid , phosphoprotein , cycloheximide , protein kinase a , phosphatase , kinase , mitogen activated protein kinase kinase , phosphorylation , map2k7 , biochemistry , biology , chemistry , microbiology and biotechnology , cancer research , cyclin dependent kinase 2 , protein biosynthesis
Treatment of MCF‐7 breast cancer cells with 50 nM okadaic acid triggers an apoptotic response which is accompanied by a 7‐fold increase in the activity of a protein kinase with a relative molecular mass of 53 kDa. The activity of the kinase was stimulated by cell treatment with inhibitors of phosphoprotein phosphatase 1 and 2A, but not by stressing conditions. Okadaic acid‐induced stimulation of the 53 kDa protein kinase was not abolished by coincubation of cells with cycloheximide. We conclude that stimulation of the 53 kDa protein kinase by inhibitors of phosphoprotein phosphatases involves pre‐existing molecular components whose activity depends on the phosphorylation state of serine/threonine residues.