How molecular motors collaborate to remodel the cytoskeleton (MEP)

What and Why

Eukaryotic cells can undergo dramatic shape changes: they move, squeeze through tight spaces, and even divide themselves. They can do this because they have a highly dynamic actin cytoskeleton, a network of protein filaments which is constantly remodelled by the motor protein myosin. We can capture the characteristic contractile behaviour of the actin cytoskeleton in vitro with just three components: actin, myosin, and a crosslinking protein. It has been shown that the amount of crosslinkers in the network determines the dynamics and length scale of contraction in such a system, but we find experimentally that small changes in the physiochemical environment can also alter the network behaviour dramatically. We think that this sensitivity comes from an often-overlooked parameter: The self-assembly of individual motor proteins into functional motor filaments, which depends strongly on the environmental conditions. 

The Project

This MEP combines numerical simulations and in vitro reconstitution experiments, and we offer it in collaboration with the Idema group (BN).

In this project you will set up simulations using Cytosim (Nedelec, 2007 New J. Phys. 9 427) to study how microscopic changes in motor assembly can translate into macroscopic changes in network contractility. You will also use purified proteins to reconstitute comparable networks in vitro, and systematically study their behavior using fluorescence microscopy.

This project is ideal for a student of (bio)physics, nanobiology, or related fields, who is motivated to combine computational and experimental approaches to understand biological questions. With support from both groups, you will be using modern computing tools as well as state of the art microscopy to study contractile actomyosin networks. 

Contact

Lucia Baldauf (l.baldauf@tudelft.nl), Gijsje Koenderink (g.h.koenderink@tudelft.nl), Timon Idema (T.Idema@tudelft.nl)

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