The glycocalyx is a complex layer that surrounds every cell in the body. It consists of sugars as well as proteins and lipids to which these sugars are attached. One could picture the glycocalyx as a cloak – indeed, “glycocalyx” means “sweet husk”. Thus, the glycocalyx is the first part of the cell that interacts with the extracellular environment – e.g. other cells, proteins, and pathogens. Importantly, the thickness of the glycocalyx amounts to many tens to several hundreds of nanometers. Therefore, all membrane proteins are literally buried under the glycocalyx. For many decades, the glycocalyx was not in the focus of research, but recent findings have shown its key importance for a range of vital cellular processes. For example, the glycocalyx is a regulator of the immune response, drives cancer progression and metastasis, and is a binding partner for pathogens, be it bacteria or viruses.
We now know that the glycocalyx is involved in such key cellular events, but we do not know how. The reason for this gap is the astounding complexity of the glycocalyx: Tens of thousands of different compounds, from small sugar “trees” on proteins to huge sugar polymers, are incredibly densely packed.
Our research aims to close this gap. We want to find out how the glycocalyx tunes the cellular state and vice versa at the mechanistic level. We employ the latest non-invasive optical methods, e.g. iSCAT and super-resolution microscopy. This enables us to access the relevant length and time scales of few nanometers and microseconds to analyze key biophysical properties of glycocalyx components like diffusion, clustering, and spatial organization. To broaden the scope of our studies, we do not only use established, highly specific labeling approaches, but also develop novel labeling strategies. We pay special attention to the cancer glycocalyx, which allows us to understand how the glycocalyx drives cancer progression and metastasis.
Have a look at a recent review from our group to get an impression of the fascinating world of the glycocalyx!