Regulating a multi-functional cytoskeletal protein (BEP)

What and Why

Eukaryotic cells rely on their actin cytoskeleton for many functions: Cell division, mobility, and even mechanical protection from the forces their environment exerts on them. Since all of these functionalities are conferred by one key player – actin – the cytoskeleton must be tightly regulated by auxiliary proteins.

In vitro reconstitution approaches, like the one we take in the consortium Building A Synthetic Cell, generally focus on reducing the number of regulatory proteins, to make the system easier to understand and experimentally more controllable. However, the evidence is mounting that to truly capture the functionality of the actin cytoskeleton, we must bring actin regulatory proteins into the in vitro system. With this project, you will be laying the groundwork for reconstituting dynamic actin cortices in vitro.

The Project

In this internship, you will purify recombinant actin regulatory proteins. You will use fluorescence spectrophotometry to characterize the functionality of these proteins and assess the effect they have on the dynamic properties of actin. Finally, you will combine the proteins in a cell-free in vitro reconstituted system to build a minimal dynamic actin cortex. You will study such minimal cortices using TIRF microscopy and, depending on your interests, also characterize their mechanical properties.

You will learn how to express and purify proteins from bacteria. You will use different techniques for characterizing a protein’s function, and get comfortable with advanced microscopy techniques. In addition to these core techniques, our group is highly collaborative and we believe in giving interns the freedom to develop their own research direction, depending on the project’s initial success and your personal interests and skills.


You participate in a Bachelor or Master study in biology, physics, chemistry or similar. You must be available for at least 4 months, although longer is preferable.


Lucia Baldauf (, Gijsje Koenderink (

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