Abstract
Calcineurin homologous protein (CHP) is an EF-hand Ca(2+)-binding protein capable of interacting with various cellular proteins including Na(+)/H(+) exchangers, kinesin-related proteins, and apoptosis-inducing protein kinase DRAK2. We investigated the role of CHP on the DRAK2 protein kinase in vitro. CHP significantly reduced (approximately 85% inhibition) the kinase activity of DRAK2 for both autophosphorylation and phosphorylation of exogenous substrate (myosin light chain). The inhibitory effect of CHP was dependent on the presence of Ca(2+), whereas the interaction between CHP and DRAK2 was not Ca(2+)-dependent. These observations suggest that CHP negatively regulates the apoptosis-inducing protein kinase DRAK2 in a manner that depends on intracellular Ca(2+)-concentration.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Apoptosis / physiology
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Apoptosis Regulatory Proteins
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COS Cells
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Calcineurin / genetics
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Calcium / chemistry
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Calcium / metabolism*
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Calcium-Binding Proteins / genetics
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Calcium-Binding Proteins / metabolism
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Calcium-Binding Proteins / pharmacology*
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Chlorocebus aethiops
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Dose-Response Relationship, Drug
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Enzyme Inhibitors / pharmacology
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Myosin Light Chains / metabolism
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Phosphorylation
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Protein Binding
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Protein Serine-Threonine Kinases / antagonists & inhibitors*
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism
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Recombinant Proteins / antagonists & inhibitors
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
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Recombinant Proteins / pharmacology
Substances
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Apoptosis Regulatory Proteins
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Calcium-Binding Proteins
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Enzyme Inhibitors
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Myosin Light Chains
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Recombinant Proteins
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Protein Serine-Threonine Kinases
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STK17B protein, human
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Calcineurin
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Calcium