CSPP1 stabilizes microtubules by capping both plus and minus ends.

Area of Science:

• Cell Biology
• Molecular Biology

Background:

• Microtubules (MTs) exhibit dynamic instability crucial for cellular functions.
• Quiescent MTs with free ends are prevalent and vital for cellular dynamics.
• Mechanisms stabilizing free MT ends are poorly understood.

Purpose of the Study:

• To investigate the role of centrosome and spindle pole protein 1 (CSPP1) in stabilizing MT ends.
• To elucidate how CSPP1 influences MT dynamics and end capping.

Main Methods:

• Real-time imaging of laser-ablated MTs in live cells.
• Analysis of MT dynamics in cells with CSPP1 overexpression and depletion.
• Assessing CSPP1's effect on MT depolymerization by kinesin.

Main Results:

• CSPP1 directly caps and stabilizes both plus and minus ends of static MTs.
• CSPP1 deposition at newly formed MT ends suppresses their dynamic instability.
• CSPP1 overexpression hyper-stabilizes MT ends; depletion increases MT dynamics.
• CSPP1 suppresses MT catastrophe and restricts polymerization.
• CSPP1-bound MTs resist kinesin-mediated depolymerization.

Conclusions:

• CSPP1 possesses a novel MT end-capping activity.
• CSPP1 integrates MT end capping to orchestrate quiescent MTs.
• This function is critical for regulating cellular dynamics powered by static MTs.