Abstract
cGMP-dependent protein kinase-I (cGK-I) induces apoptosis in various cancer cell lines. However, the signaling mechanisms involved remain unknown. Using protein microarray technology, we identified a novel cGK substrate, death-associated protein kinase 2 (DAPK2), which is a Ca(2+)/calmodulin-regulated serine/threonine kinase. cGK-I phosphorylated DAPK2 at Ser(299), Ser(367) and Ser(368). Interestingly, a phospho-mimic mutant, DAPK2 S299D, significantly enhanced its kinase activity in the absence of Ca(2+)/calmodulin, while a S367D/S368D mutant did not. Overexpression of DAPK2 S299D also resulted in a twofold increase in apoptosis of human breast cancer MCF-7 cells as compared with wild-type DAPK2. These results suggest that DAPK2 is one of the targets of cGK-I in apoptosis induction.
Copyright © 2012 Elsevier Inc. All rights reserved.
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 Regulatory Proteins / genetics
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Apoptosis Regulatory Proteins / metabolism*
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Apoptosis*
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COS Cells
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Calcium-Calmodulin-Dependent Protein Kinases / genetics
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Calcium-Calmodulin-Dependent Protein Kinases / metabolism*
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Cell Line, Tumor
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Chlorocebus aethiops
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Cyclic GMP-Dependent Protein Kinase Type I
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Cyclic GMP-Dependent Protein Kinases / metabolism*
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Death-Associated Protein Kinases
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Enzyme Activation
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Humans
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Mice
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Mutation
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Phosphorylation
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Protein Array Analysis
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Serine / genetics
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Serine / metabolism
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Substrate Specificity
Substances
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Apoptosis Regulatory Proteins
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Serine
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DAPK2 protein, human
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Death-Associated Protein Kinases
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dapk2 protein, mouse
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Cyclic GMP-Dependent Protein Kinase Type I
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Cyclic GMP-Dependent Protein Kinases
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PRKG1 protein, human
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Prkg1 protein, mouse
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Calcium-Calmodulin-Dependent Protein Kinases