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Updated: Jun 29, 2025
12:26
Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay
Published on: May 3, 2018
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CDK activity at the centrosome regulates the cell cycle.
Emma L Roberts1, Jessica Greenwood1, Nitin Kapadia1
1Cell Cycle Laboratory, The Francis Crick Institute, NW1 1AT London, UK.
Cell Reports
|April 5, 2024
Summary
The hydrophobic patch on mitotic cyclins is crucial for their localization to centrosomes, which is essential for cell division. Restoring this localization enables entry into mitosis and CDK substrate phosphorylation.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Mitotic cyclin localization to centrosomes is vital for cell division.
- A hydrophobic patch on cyclins is known to be important for this localization.
- Mutations in this patch can disrupt mitosis, but the exact cause is unclear.
Purpose of the Study:
- To investigate whether defective centrosomal localization or broader substrate docking is responsible for mitotic defects caused by a hydrophobic patch mutant (HPM) in fission yeast cyclin Cdc13.
- To determine the role of the S-phase B-cyclin hydrophobic patch in centrosomal localization and S phase progression.
Main Methods:
- Utilized a hydrophobic patch mutant (HPM) of fission yeast mitotic cyclin Cdc13.
- Artificially restored centrosomal localization of the Cdc13-HPM mutant.
- Assessed mitotic entry and cyclin-dependent kinase (CDK) substrate phosphorylation at the centrosome and cytoplasm.
- Examined the role of the S-phase B-cyclin hydrophobic patch.
Main Results:
- Artificial restoration of Cdc13-HPM centrosomal localization rescued mitotic entry.
- Increased CDK substrate phosphorylation was observed at the centrosome and in the cytoplasm upon restoring localization.
- The S-phase B-cyclin hydrophobic patch is necessary for centrosomal localization but not for S phase progression.
Conclusions:
- The hydrophobic patch is essential for mitosis due to its role in concentrating cyclin-CDK complexes with substrates and regulators at the centrosome.
- The centrosome acts as a critical hub for coordinating cell-cycle control.
- This study explains the essential nature of the cyclin hydrophobic patch for successful mitosis.
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