Identification of a new form of death-associated protein kinase that promotes cell survival.
In this study, two alternatively spliced forms of the mouse death-associated protein kinase (DAPK) have been identified and their roles in apoptosis examined. The mouse DAPK-alpha sequence is 95% identical to the previously described human DAPK, and it has a kinase domain and calmodulin-binding region closely related to the 130-150 kDa myosin light chain kinases. A 12-residue extension of the carboxyl terminus of DAPK-beta distinguishes it from the human and mouse DAPK-alpha. DAPK phosphorylates at least one substrate in vitro and in vivo, the myosin II regulatory light chain. This phosphorylation occurs preferentially at Ser-19 and is stimulated by calcium and calmodulin. The mRNA encoding DAPK is widely distributed and detected in mouse embryos and most adult tissues, although the expression of the encoded 160-kDa DAPK protein is more restricted. Overexpression of DAPK-alpha, the mouse homolog of human DAPK has a negligible effect on tumor necrosis factor (TNF)-induced apoptosis. Overexpression of DAPK-beta has a strong cytoprotective effect on TNF-treated cells. Biochemical analysis of TNF-treated cell lines expressing mouse DAPK-beta suggests that the cytoprotective effect of DAPK is mediated through both intrinsic and extrinsic apoptotic signaling pathways and results in the inhibition of cytochrome c release from the mitochondria as well as inhibition of caspase-3 and caspase-9 activity. These results suggest that the mouse DAPK-beta is a negative regulator of TNF-induced apoptosis.
Jin
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Department of Cellular and Integrated Physiology, Indiana University School of Medicine, 635 Barnhill Dr., Indianapolis, IN 46202, USA.
Blue
E K
EK
Dixon
S
S
Hou
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L
Wysolmerski
R B
RB
Gallagher
P J
PJ
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics* / Q000378:metabolism*; D064550:Death-Associated Protein Kinases; D051379:Mice; D008969:Molecular Sequence Data; D018994:Myosin Light Chains / Q000378:metabolism; D024462:Myosin Type II / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D010766:Phosphorylation; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014018:Tissue Distribution; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D051017:Apoptosis Regulatory Proteins; D018994:Myosin Light Chains; D016328:NF-kappa B; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D064550:Death-Associated Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D024462:Myosin Type II