CENP-W plays a role in maintaining bipolar spindle structure

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• The CENP-W/T complex is crucial for proper mitosis.
• CENP-W depletion leads to mitotic defects including disorganized prometaphases and multipolar spindles.

Purpose of the Study:

• To investigate the mechanism of multipolar spindle formation upon CENP-W depletion.
• To understand the role of CENP-W in maintaining spindle pole integrity.

Main Methods:

• HeLa cells depleted of CENP-W were analyzed using fluorescent proteins for histone H2B and tubulin.
• Immunofluorescence microscopy was used to examine centrioles and centrosomal markers.
• Experiments involved nocodazole arrest, monastrol treatment, and TPX2 overexpression.

Main Results:

• CENP-W depletion caused rapid fragmentation of bipolar spindles and depletion of Hec1 at kinetochores.
• Centrioles were abnormally split, and supernumerary poles often lacked centrioles.
• Spindle pole fragmentation was microtubule-dependent, involved Eg5, and was suppressed by TPX2 overexpression.
• CENP-W depletion rescued monastrol-induced monopolar spindles, promoting bipolarity.

Conclusions:

• CENP-W is essential for stable kinetochore-microtubule attachments, resisting motor protein forces.
• Defective kinetochores contribute to spindle pole disruption via mechanical forces.
• Centrosome integrity is regulated by pathways controlling kinetochore-microtubule attachment stability.