RESEARCH

OVERARCHING GOAL

The interior of the cell is unlike a dilute buffer. However, traditionally, most biochemistry experiments have been performed in a dilute buffer. To understand how the interior of the cell influences biochemical processes, such as the organization of the biopolymers, we need to know the important parameters in the cell and quantify their contribution to the intracellular organization.

We aim to improve our understanding of the intracellular molecular self-organization by:

1) measuring relevant parameters in living cells using novel probes, such as crowding and (pathogenic) protein self-assembly/aggregation

2) perturbing such parameters in living cells,

3) Reconstruct aspects of the living cell organization in artificial systems.

Examples of some of our sensors are below:

MACROMOLECULAR CROWDING

We study macromolecular crowding with our unique sensors, which we developed. The sensors provide a readout for the excluded volume in bacteria under stress, aging yeast cells, and mammalian cells. Our efforts are to improve these sensors and map macromolecular crowding in different species and conditions.

IONIC STRENGTH

We developed genetically encoded sensors that measure ionic strength. Ionic strength is important for anything charged, including pretty much every molecule in the living cell (apart from a few small molecules). Our FRET-based ionic strength sensor allows determining the ionic strength inside living cells, with all the advantages of FRET-based genetically encoded sensors, such as high spatiotemporal resolution and easy targeting to different compartments.

PROTEIN SELF-ORGANIZATION

We engineered proteins that allow the self-assembly of proteins in cells to be observed and their structural transition assessed. It provides a precise readout of minor variations through continuous monitoring. Notably, this probing method also gives a fast readout, for example by FACS, and can be applied to aggregating proteins (mutants of Huntingtin protein associated with Huntington's disease) and condensate forming proteins (such as mutants of the FUS protein associated with some forms of ALS).