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PhD defense of van C. Yang MSc

End Binding proteins orchestrate microtubule plus- and minus-end dynamics

The microtubule cytoskeleton is very important for various cellular activities. Microtubules are dynamic and they can rapidly switch between phases of growth and shrinkage. The End binding proteins (EBs) can track and accumulate at growing microtubule plus ends. In this thesis, we give insight into the molecular mechanism of how EBs control microtubule plus- and minus-end dynamics.

More compact Golgi

First, we generated a series of EB1, EB2 and EB3 mutant cell lines. Surprisingly, we found that CAMSAP2 stabilized microtubule minus ends were detached from the Golgi and the Golgi became more compact in these cells. Further studies showed that the EB1/EB3-myomegalin interaction can tether microtubules to the Golgi and counteract compaction of Golgi stacks. In addition, we investigated how EBs and their partners affect the properties of growing microtubule plus ends. We found a stable, depolymerization-resistant microtubule zone in the tip-proximal region, which showed higher mobility in the EB1/EB2/EB3 triple knockout cells.

Microtubule tip regulation

We also explored the role of liquid-liquid phase separation in microtubule tip regulation. We found that SLAIN2 can undergo phase separation and form droplets both in vitro and in cells. In cells, SLAIN2 scaffolds recruit EBs and chTOG but not CLASP and CLIP170. In vitro, SLAIN2 and chTOG, but not EB3, can form droplets, and chTOG scaffolds could nucleate microtubule asters. Furthermore, we investigated how different microtubule binding domains could affect microtubule dynamics when targeted to microtubule tips by the N-terminal part of EB3. Our results indicate that different parameters of microtubule dynamics can be regulated independently of each other.

Start date and time
End date and time
Location
Online
PhD candidate
C. Yang MSc
Dissertation
End Binding proteins orchestrate microtubule plus- and minus-end dynamics
PhD supervisor(s)
prof. dr. A.S. Akhmanova