Force generation and (regulated) dynamics at microtubule ends

Marian Baclayon, Georges Weber
Collaborators: Prof. Peter Peters group in Maastricht University and FEI company

The assembly of microtubules generates forces that play a role in the organization of cellular structures and in dynamic processes such as spindle formation and chromosome segregation during cell division. Over the years we have developed a unique set of in-vitro experimental techniques that allows for quantitative measurements of the dynamics of microtubules when generating force in contact with a barrier. In addition, we have demonstrated that in living cells, where a complete set of microtubule regulatory proteins is present, force has a clearly measurable effect on the dynamics of microtubules as well.

Our focus is to establish how microtubule regulatory proteins and motors, in combination with force, operate to regulate microtubule dynamics in a functional way. Our approach is based on an optical tweezers technique with force-feedback where the dynamics and forces of a microtubule interacting with a micro-fabricated barrier can be followed with nanometer-resolution. In combination with our recent capability of reconstituting an in-vitro microtubule plus-end tracking system with proteins derived from the fission yeast, this allows for a careful quantitative investigation of how end-tracking proteins and motors affect the dynamics of both freely growing microtubules and microtubules that are generating force in contact with an (artificial) barrier. With cryo-EM imaging, we are also investigating how these end-tracking proteins and motors are structurally and physically interacting with the microtubule ends.