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Studying Cell Cycle-regulated Gene Expression by Two Complementary Cell Synchronization Protocols
Published on: June 6, 2017
Cell cycle and activation of CK2
Miwako Kato Homma1, Yoshimi Homma
1Department of Biomolecular Science, Fukushima Medical University School of Medicine, 1-Hikari-gaoka, Fukushima, 960-1295, Japan. mkhomma@fmu.ac.jp
Molecular and Cellular Biochemistry
|July 24, 2008
Summary
Casein kinase 2 (CK2) activation regulates cell cycle progression. CK2 phosphorylates eukaryotic translation-initiation factor eIF5, impacting cell growth and protein expression.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Casein kinase 2 (CK2) is a conserved eukaryotic protein kinase involved in cell proliferation and signal transduction.
- CK2 has been considered constitutively non-regulated, with its precise regulatory mechanisms remaining unclear.
Purpose of the Study:
- To investigate the regulation of CK2 during cell cycle progression.
- To identify downstream targets of CK2 involved in cell cycle control.
- To elucidate the role of eIF5 phosphorylation by CK2 in cell cycle progression.
Main Methods:
- Cell synchronization and stimulation with FBS.
- Analysis of CK2 activity during cell cycle progression.
- Identification and characterization of CK2 substrates using biochemical and genetic approaches.
- Western blotting to detect protein phosphorylation and expression.
- Subcellular fractionation to determine CK2 localization.
Main Results:
- CK2 activation was observed during cell cycle progression in response to FBS stimuli in G0-arrested cells.
- The eukaryotic translation-initiation factor eIF5 was identified as a direct substrate of CK2, phosphorylated at Ser389 and Ser390.
- Expression of eIF5 phosphorylation site mutants demonstrated dominant-negative effects on endogenous eIF5 phosphorylation, complex formation, growth rate, and cell cycle-regulated protein expression.
- Activated CK2 translocates to the nuclear fraction during cell cycle progression.
Conclusions:
- CK2 activity is regulated during the cell cycle.
- Phosphorylation of eIF5 by CK2 plays a critical role in cell cycle progression.
- CK2 regulates cell cycle progression through phosphorylation of translation initiation factors and nuclear substrates upon its activation.
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