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The p34cdc2-related cyclin-dependent kinase 11 interacts with the p47 subunit of eukaryotic initiation factor 3
Jiaqi Shi1, Yongmei Feng, Anne-Christine Goulet
1Department of Pathology, Arizona Cancer Center, University of Arizona, Tucson, Arizona 85724, USA.
Abstract:
Cyclin-dependent kinase 11 (CDK11; also named PITSLRE) is part of the large family of p34(cdc2)-related kinases whose functions appear to be linked with cell cycle progression, tumorigenesis, and apoptotic signaling. However, substrates of CDK11 during apoptosis have not been identified. We used a yeast two-hybrid screening strategy and identified eukaryotic initiation factor 3 p47 protein (eIF3 p47) as an interacting partner of caspase-processed C-terminal kinase domain of CDK11 (CDK11(p46)). We demonstrate that the eIF3 p47 can interact with CDK11 in vitro and in vivo, and the interaction can be strengthened by stimulation of apoptosis. EIF3 p47 contains a Mov34/JAB domain and appears to interact with CDK11(p46) through this motif. We show in vitro that the caspase-processed CDK11(p46) can phosphorylate eIF3 p47 at a specific serine residue (Ser(46)) and that eIF3 p47 is phosphorylated in vivo during apoptosis. Purified recombinant CDK11(p46) inhibited translation of a reporter gene in vitro in a dose-dependent manner. In contrast, a kinase-defective mutant CDK11(p46M) did not inhibit translation of the reporter gene. Stable expression of CDK11(p46) in vivo inhibited the synthesis of a transfected luciferase reporter protein and overall cellular protein synthesis. These data provide insight into the cellular function of CDK11 during apoptosis.
Insights
Cyclin-dependent kinase 11 (CDK11) phosphorylates eukaryotic initiation factor 3 p47 (eIF3 p47) during apoptosis, inhibiting protein synthesis. This reveals a novel role for CDK11 in regulating cellular processes during programmed cell death.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Cyclin-dependent kinase 11 (CDK11) is implicated in cell cycle, tumorigenesis, and apoptosis.
- Specific substrates of CDK11 during apoptosis remain unidentified.
Purpose of the Study:
- To identify substrates of CDK11 during apoptosis.
- To elucidate the function of CDK11-interacting proteins in apoptotic signaling.
Main Methods:
- Yeast two-hybrid screening to identify CDK11 interacting partners.
- In vitro and in vivo interaction assays.
- In vitro kinase assays and reporter gene translation assays.
- In vivo protein synthesis inhibition studies.
Main Results:
- Eukaryotic initiation factor 3 p47 (eIF3 p47) was identified as a CDK11 interacting partner.
- CDK11 directly phosphorylates eIF3 p47 at Serine 46 during apoptosis.
- CDK11 inhibits reporter gene translation and cellular protein synthesis in a kinase-dependent manner.
Conclusions:
- CDK11 directly interacts with and phosphorylates eIF3 p47 during apoptosis.
- CDK11's kinase activity is crucial for inhibiting protein synthesis in apoptotic cells.
- This study uncovers a novel mechanism for CDK11 in regulating protein synthesis during apoptosis.