Abstract
Death-associated protein kinase (DAPK) is a multi-domain Ser/Thr protein kinase with an important role in apoptosis regulation. In these studies we have identified a DAPK-interacting protein called DIP-1, which is a novel multi-RING finger protein. The RING finger motifs of DIP-1 have E3 ligase activity that can auto-ubiquitinate DIP-1 in vitro. In vivo, DIP-1 is detected as a polyubiquitinated protein, suggesting that the intracellular levels of DIP-1 are regulated by the ubiquitin-proteasome system. Transient expression of DIP-1 in HeLa cells antagonizes the anti-apoptotic function of DAPK to promote a caspase-dependent apoptosis. These studies also demonstrate that DAPK is an in vitro and in vivo target for ubiquitination by DIP-1, thereby providing a mechanism by which DAPK activities can be regulated through proteasomal degradation.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Animals
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Apoptosis Regulatory Proteins
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Apoptosis*
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Blotting, Northern
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Blotting, Western
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COS Cells
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Calcium-Calmodulin-Dependent Protein Kinases / chemistry
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Calcium-Calmodulin-Dependent Protein Kinases / metabolism*
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Cell Line
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Cloning, Molecular
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Cysteine Endopeptidases / metabolism
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Death-Associated Protein Kinases
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Dose-Response Relationship, Drug
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Electrophoresis, Polyacrylamide Gel
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Flow Cytometry
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Fungal Proteins / metabolism
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Gene Expression Regulation, Enzymologic*
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HeLa Cells
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Humans
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Ligases / biosynthesis*
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Ligases / chemistry*
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Mice
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Molecular Sequence Data
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Multienzyme Complexes / metabolism
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Precipitin Tests
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Proteasome Endopeptidase Complex
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Protein Binding
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Recombinant Fusion Proteins / metabolism
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Sequence Homology, Amino Acid
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Substrate Specificity
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Time Factors
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Tissue Distribution
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Tumor Necrosis Factor-alpha / metabolism*
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Two-Hybrid System Techniques
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Ubiquitin / metabolism
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Ubiquitin-Protein Ligases
Substances
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Apoptosis Regulatory Proteins
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Fungal Proteins
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Multienzyme Complexes
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Recombinant Fusion Proteins
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Tumor Necrosis Factor-alpha
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Ubiquitin
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MIB1 protein, mouse
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Ubiquitin-Protein Ligases
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Death-Associated Protein Kinases
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Calcium-Calmodulin-Dependent Protein Kinases
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Cysteine Endopeptidases
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Proteasome Endopeptidase Complex
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Ligases