A unique insertion in STARD9's motor domain regulates its stability
Silvia Senese1, Keith Cheung1, Yu-Chen Lo2
1Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095.
Molecular Biology of the Cell
|December 16, 2014
Summary
STARD9 protein levels are regulated by phosphorylation and degradation during mitosis. This regulation by Plk1 and SCFβ-TrCP is crucial for proper spindle assembly and cell division.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- STARD9 is an uncharacterized mitotic kinesin involved in spindle assembly.
- Its precise regulatory mechanisms and role in cell division remain unclear.
- Understanding STARD9 regulation is vital as it's a potential cancer target.
Purpose of the Study:
- To investigate the factors controlling STARD9 stability.
- To elucidate the mechanisms regulating the STARD9 motor domain.
- To understand STARD9's role in mitotic spindle assembly.
Main Methods:
- Biochemical assays to study STARD9 motor domain.
- Phosphorylation site mapping using mass spectrometry.
- Ubiquitination assays with SCFβ-TrCP ligase.
- Analysis of STARD9 mutants in cell division.
Main Results:
- STARD9 possesses a unique motor domain insertion compared to other kinesins.
- STARD9 motor domain is phosphorylated by Plk1 during mitosis.
- Phosphorylation targets STARD9 for SCFβ-TrCP mediated degradation.
- Mutants resistant to phosphorylation and degradation cause spindle assembly defects.
Conclusions:
- STARD9 protein levels are dynamically regulated by Plk1 and SCFβ-TrCP during mitosis.
- This regulation is essential for maintaining proper mitotic spindle assembly.
- Targeting STARD9 degradation pathways may offer therapeutic strategies for cancer.
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