Studying the dynamics of cytoskeletal polymers in membraneless compartments

We are all familiar with the phenomenon of phase separation between two immiscible liquids, such as oil-in-water droplets. Recently, a series of exciting scientific discoveries have revealed that cells use liquid-liquid phase separation all the time to regulate their internal biochemistry1! Thus, in addition to the well-known membrane-bound confinements like mitochondria, cells possess numerous membraneless organelles (MOs) like the nucleolus and germ granules. While the role of MOs in enhancing biochemical reactions is well-known, their impact on physical manipulation of the local environment such as membranes and intracellular polymer networks is unclear.

In this project you will investigate how actin, a major protein involved in maintaining cell shape and driving motility, is affected in presence of MOs. You will design simple microfluidic chips to study actin biochemistry in MOs, such as their polymerization rates and network properties. Once properly characterized, we will further study this system within liposomes to assess its interaction with lipid membranes. This will be done with the help of OLA2, a microfluidic technique to produce liposomes in a high-throughput manner, which already has been proved as a promising tool to form MOs3.

Figure 1. Schematic of actin network formation within MO, followed by deformation and disintegration of the entire structure.
Figure 1. Schematic of actin network formation within MO, followed by deformation and disintegration of the entire structure.

If you want to get hands-on experience with microfluidics, fluorescence microscopy, handling proteins and the exciting phenomenon of liquid-liquid phase separation, just drop us an email (siddharth.deshpande@wur.nl) or pass by our lab/office (Helix, 7056).

References

1.         Shin, Y. & Brangwynne, C. P. Liquid phase condensation in cell physiology and disease. Science 357, eaaf4382 (2017).

2.         Deshpande, S., Caspi, Y., Meijering, A. E. C. & Dekker, C. Octanol-assisted liposome assembly on chip. Nat. Commun. 7, 10447 (2016).

3.         Deshpande, S. et al. Spatiotemporal control of coacervate formation within liposomes. Nat. Commun. 10, 1800 (2019).