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Updated: Jul 3, 2026
Live Cell Imaging to Assess the Dynamics of Metaphase Timing and Cell Fate Following Mitotic Spindle Perturbations
Published on: September 20, 2019
Aurora-A and ch-TOG act in a common pathway in control of spindle pole integrity
M De Luca1, L Brunetto, I A Asteriti
1Institute of Molecular Biology and Pathology, CNR, c/o University of Rome La Sapienza, Rome, Italy.
Abstract:
Mitotic spindle assembly is a highly regulated process, crucial to ensure the correct segregation of duplicated chromosomes in daughter cells and to avoid aneuploidy, a common feature of tumors. Among the most important spindle regulators is Aurora-A, a mitotic centrosomal kinase frequently overexpressed in tumors. Here, we investigated the role of Aurora-A in spindle pole organization in human cells. We show that RNA interference-mediated Aurora-A inactivation causes pericentriolar material fragmentation in prometaphase, yielding the formation of spindles with supernumerary poles. This fragmentation does not necessarily involve centrioles and requires microtubules (MTs). Aurora-A-depleted prometaphases mislocalize the MT-stabilizing protein colonic hepatic tumor-overexpressed gene (ch-TOG), which abnormally accumulates at spindle poles, as well as the mitotic centromere-associated kinesin (MCAK), the major functional antagonist of ch-TOG, which delocalizes from poles. ch-TOG is required for extrapole formation in prometaphases lacking Aurora-A, because co-depletion of Aurora-A and ch-TOG mitigates the fragmented pole phenotype. These results indicate a novel function of Aurora-A, the regulation of ch-TOG and MCAK localization, and highlight a common pathway involving the three factors in control of spindle pole integrity.
Insights
Aurora-A kinase is vital for organizing mitotic spindle poles. Its depletion causes fragmentation and supernumerary poles by mislocalizing ch-TOG and MCAK, highlighting a key pathway for spindle integrity.
Area of Science:
- Cell Biology
- Molecular Biology
- Cancer Biology
Background:
- Mitotic spindle assembly ensures accurate chromosome segregation, preventing aneuploidy, a hallmark of cancer.
- Aurora-A kinase, a centrosomal kinase, is frequently overexpressed in tumors and plays a critical role in spindle regulation.
Purpose of the Study:
- To investigate the role of Aurora-A in organizing spindle poles in human cells.
- To elucidate the molecular mechanisms by which Aurora-A influences spindle pole integrity.
Main Methods:
- RNA interference (RNAi) was used to deplete Aurora-A in human cells.
- Immunofluorescence microscopy was employed to analyze spindle pole organization, pericentriolar material, and the localization of key proteins.
- Co-depletion experiments were performed to assess the functional relationship between Aurora-A, ch-TOG, and MCAK.
Main Results:
- Aurora-A inactivation led to pericentriolar material fragmentation and the formation of spindles with supernumerary poles.
- This fragmentation was dependent on microtubules but not necessarily centrioles.
- Aurora-A depletion caused mislocalization of the microtubule-stabilizing protein ch-TOG and the kinesin MCAK, a functional antagonist of ch-TOG.
- Co-depletion of Aurora-A and ch-TOG rescued the fragmented pole phenotype, indicating ch-TOG's requirement for abnormal pole formation.
Conclusions:
- Aurora-A plays a novel role in regulating the localization of ch-TOG and MCAK.
- A common pathway involving Aurora-A, ch-TOG, and MCAK is crucial for maintaining spindle pole integrity.
- Dysregulation of this pathway may contribute to aneuploidy observed in tumors.
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