In more complex organisms like humans, very dynamic proteins, so called intrinsically disordered proteins (IDPs) enriched. Those proteins are most famous for their involvement in misfolding neurodegenerative aging diseases like Alzheimer, Parkinson, Huntington. However, they are actually key to many important and precise cellular mechanisms, likely because the ability to encode multiple tasks into those dynamic polymer like proteins vs more stable proteins apparently outweighs the seeming disadvantages. This was likely key to evolution of more complex species. Studying such highly dynamics is a major challenge and requires novel technology development. The ability to observe single molecules using fluorescence was awarded in 2014 with the Nobel Prize in Chemistry, as it enables a direct look on how fundamental molecular processes work in biology. This ultimately gives an unbiased view at how the molecular building blocks of live are designed by nature, and how they function together. Furthermore, malfunctions in such processes can be directly visualized using modern spectroscopy and microscopy techniques, which is of high relevance for health and society.
Despite all progress, single molecule fluorescence science suffers from the need for site-specific labelling and the intrinsic low throughput. In this project, we aimed to improve single molecule science, by integrating chemical biology and microfluidic tools into a synergistic process on how to study disordered biological building blocks with high resolution. The tools were directly used to study a set of IDPs highly relevant to a fundamental function of the eukaryotic cell, which in turn also feedbacks on the tool development.
In the eukaryotic cell all genetic material is stored in the nucleus, which for example protects it modifications due to pathogens, like viruses. However, constant information exchange in the form of biomolecules entering and exiting the nucleus is essential for cellular function. Intrinsically disordered proteins termed nucleoporins form a permeability barrier of still elusive nature inside nuclear pore complexes spanning the nuclear envelope. While key to controlling nucleocytoplasmic transport, likely due to their disordered nature, many of those proteins can also take on vital functions in processes like gene regulation elsewhere in the cell. The fundamental principles behind such multifunctionality are largely unknown.
