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Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay
Published on: May 3, 2018
Polo-like kinase interacts with proteasomes and regulates their activity
Y Feng1, D L Longo, D K Ferris
1Biological Mechanisms Section, Laboratory of Leukocyte Biology, National Cancer Institute-Frederick Cancer Research and Development Center, Maryland 21702, USA.
Cell Growth & Differentiation : the Molecular Biology Journal of the American Association for Cancer Research
|February 24, 2001
Summary
Polo-like kinase (Plk) regulates proteasome activity by phosphorylating its subunits. This phosphorylation enhances the proteasome
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Polo-like kinase (Plk) is involved in cell cycle regulation, particularly at the metaphase to anaphase transition.
- Plk interacts with the anaphase-promoting complex and influences ubiquitination, a key process for protein degradation.
- The proteasome is a multi-subunit protease complex responsible for degrading ubiquitinated proteins.
Purpose of the Study:
- To investigate the interaction between Plk and proteasomal proteins.
- To determine if Plk directly regulates proteasome activity through phosphorylation.
- To elucidate the role of Plk in mitotic regulation of proteasome function.
Main Methods:
- Mass spectrometry to identify Plk-interacting proteasomal proteins.
- Immunoprecipitation assays using human CA46 and HEK 293 cells.
- In vitro and in vivo phosphorylation studies using baculovirus-expressed Plk and metabolic labeling.
- Assays to measure proteasome proteolytic activity.
Main Results:
- Plk was found to interact with 20S proteasome subunits.
- Plk directly phosphorylates proteasome subunits C9 and C8 in vivo.
- Phosphorylation of proteasomes by Plk enhanced their proteolytic activity.
- Plk association with 26S proteasomes was observed under specific conditions.
Conclusions:
- Plk is a novel regulator of proteasome activity.
- Plk-mediated phosphorylation of proteasomes influences their function.
- Plk plays a significant role in the mitotic regulation of the ubiquitin-proteasome system.
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