Colloquium: Elias Puchner

Cellular processes are regulated by complex interactions of biomolecules. The spatio-temporal organization of these biomolecules such as their localization to intracellular organelles is critical for their function. With the breakthrough of optical single-molecule and super-resolution microscopy techniques it became possible to study the spatio-temporal organization of biomolecules on a nanoscopic length scale far below the optical diffraction limit of conventional microscopes. However, challenges remained for quantifying the abundance of biomolecules and for investigating living cells. Here, I will present our novel developments of quantitative live-cell super-resolution microscopy techniques as well as improved fluorescent probes that overcome these limitations. I will exemplify the power of such precision measurements by presenting our new insights in the protein complex initiating autophagosome formation, which degrades and recycles cellular components. Furthermore, we gained a deeper understanding of lipid droplet regulation by following fatty acid incorporation and changes in enzyme densities based on metabolic needs of cells. In my outlook I will summarize how ongoing and future applications of these techniques enable us to study phase transitions of regulatory proteins and to establish collaborative projects of biomedical relevance.