Plk1 and Mps1 Cooperatively Regulate the Spindle Assembly Checkpoint in Human Cells
Conrad von Schubert1, Fabien Cubizolles1, Jasmine M Bracher1
1Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.
Cell Reports
|June 30, 2015
Summary
Human Plk1 kinase cooperates with Mps1 to strengthen the spindle assembly checkpoint (SAC). Plk1 enhances Mps1 activity and the recruitment of key SAC proteins to kinetochores, ensuring accurate chromosome segregation.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Accurate mitotic chromosome segregation is essential for maintaining genome integrity.
- The spindle assembly checkpoint (SAC) monitors this process.
- The SAC kinase Monopolar spindle 1 (Mps1) shares a phosphorylation motif with Polo-like kinase 1 (Plk1).
Purpose of the Study:
- To investigate whether human Plk1 cooperates with Mps1 in SAC signaling.
- To elucidate the role of Plk1 in SAC establishment and maintenance.
Main Methods:
- Phosphorylation analysis of Mps1 substrates.
- Assessment of kinetochore recruitment of SAC components.
- Enzyme activity assays for Mps1.
Main Results:
- Plk1 promotes SAC signaling at kinetochores by phosphorylating Mps1 substrates, including KNL-1 and Mps1.
- Plk1 enhances Mps1 catalytic activity.
- Plk1 facilitates the recruitment of Mad1:C-Mad2 and Bub3:BubR1 complexes to kinetochores.
Conclusions:
- Plk1 acts as a crucial co-factor with Mps1 in SAC regulation.
- Plk1 strengthens SAC establishment at mitosis onset.
- Plk1 supports SAC maintenance during extended mitotic arrest, ensuring genome stability.
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