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Updated: May 20, 2026
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Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay
Published on: May 3, 2018
SAPCD2 phosphorylation modulates astral microtubule stability to control spindle orientation
Shuang Chen1,2, Ying Hong1, Yaping Fang1
1State Key Laboratory of Swine and Poultry Breeding Industry, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China.
Communications Biology
|May 18, 2026
Summary
Suppressor APC domain-containing 2 (SAPCD2) links microtubule stability to spindle orientation. Phosphorylation during mitosis creates a form of SAPCD2 that destabilizes microtubules, ensuring proper cell division.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Accurate spindle orientation is crucial for organogenesis and tissue homeostasis.
- Cortical tethering complexes, like the Gαi-LGN-NuMA complex, anchor astral microtubules for spindle guidance.
- The link between astral microtubule stability and mitosis-dependent regulation is not fully understood.
Purpose of the Study:
- To identify cell cycle-regulated factors controlling astral microtubule stability and spindle orientation.
- To elucidate the mechanism by which SAPCD2 influences microtubule dynamics during mitosis.
- To investigate the role of SAPCD2 phosphorylation in regulating spindle orientation.
Main Methods:
- Utilized non-polarized HeLa and HaCaT cell culture models.
- Employed live-cell imaging to observe spindle behavior.
- Used siRNA-mediated depletion of SAPCD2 and analyzed the effects of specific phosphorylation site mutations.
Main Results:
- SAPCD2 depletion led to spindle misorientation, mitotic delay, and aberrant cell division.
- SAPCD2 functions as a microtubule-associated protein promoting microtubule stability.
- CDK1-mediated phosphorylation at S157 and S27 generates a mitosis-specific isoform that destabilizes astral microtubules; disruption of this phosphorylation prevents rescue of spindle misorientation.
Conclusions:
- SAPCD2 is a key cell cycle-regulated factor linking astral microtubule stability to spindle orientation control.
- Mitosis-dependent dynamic phosphorylation of SAPCD2 fine-tunes astral microtubule behavior.
- These findings enhance understanding of the molecular mechanisms ensuring accurate spindle orientation during cell division.
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