Puppeteering of microtubule-kinetochore coupling proteins: On the molecular control of minimal spindles

This thesis presents the use of DNA origami nanosprings to investigate the mechanical basis of chromosome segregation, focusing on microtubule-kinetochore (Ndc80) force transmission.

Traditional force measurement techniques lack control over protein interactions. The nanosprings were developed as accessible force sensors and validated against optical trapping, successfully measuring piconewton forces from growing and shrinking microtubules.

A key finding is the stoichiometric control of kinetochore function: by varying the number of atruncated version Ndc80 (jubaea) on the nanosprings, the study demonstrated that microtubule stability and force capture are critically tuned by protein copy number, with higher valency (15-20 copies) leading to significant microtubule stabilization and rescue, mirroring native kinetochore behavior.

The work establishes the DNA nanospring as a powerful tool to dissect mitotic mechanics, revealing that cellular mitotic fidelity depends fundamentally on dynamic protein stoichiometry. It also lays the foundation for reconstituting minimal mitotic spindle systems.