Abstract
Many protein kinases themselves are regulated by reversible phosphorylation. Upon cell stimulation, specific kinases are transiently phosphorylated and activated. Several of these protein kinases are substrates for protein phosphatase 2A (PP2A), and PP2A appears to be the major kinase phosphatase in eukaryotic cells that downregulates activated protein kinases. This idea is substantiated by the observation that some viral proteins and naturally occurring toxins target PP2A and modulate its activity. There is increasing evidence that PP2A activity is regulated by extracellular signals and during the cell cycle. Thus, PP2A is likely to play an important role in determining the activation kinetics of protein kinase cascades.
Publication types
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Research Support, Non-U.S. Gov't
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Review
MeSH terms
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Calcium-Calmodulin-Dependent Protein Kinases / metabolism
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Cell Cycle Proteins*
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Cyclin-Dependent Kinases / metabolism
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Dual Specificity Phosphatase 1
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I-kappa B Kinase
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Immediate-Early Proteins / metabolism
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Phosphoprotein Phosphatases / chemistry*
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Phosphoprotein Phosphatases / metabolism*
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Protein Kinase C / metabolism
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Protein Kinases / metabolism*
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Protein Phosphatase 1
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Protein Phosphatase 2
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Protein Serine-Threonine Kinases / metabolism
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Protein Tyrosine Phosphatases / metabolism
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins c-akt
Substances
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Cell Cycle Proteins
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Immediate-Early Proteins
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Proto-Oncogene Proteins
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Protein Kinases
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Protein Serine-Threonine Kinases
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Proto-Oncogene Proteins c-akt
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I-kappa B Kinase
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Protein Kinase C
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Calcium-Calmodulin-Dependent Protein Kinases
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Cyclin-Dependent Kinases
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Phosphoprotein Phosphatases
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Protein Phosphatase 1
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Protein Phosphatase 2
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Dual Specificity Phosphatase 1
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Protein Tyrosine Phosphatases