Speaker: Elias M. Puchner

University of Minnesota,
School of Physics and Astronomy


Title: Exploring intra-cellular processes at the nanoscopic length scale with quantitative single-molecule microscopy in living cells


Abstract: 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 such as Single Molecule Localization Microscopy (SMLM) 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 developments for quantitative live-cell SMLM techniques as well as improved fluorescent probes that overcome these limitations. First, I will present a characterization of chromatin structure and dynamics in living cells using telomeres as a model system. I will then present our surprising finding of SMLM based on ground-state dimers of conventional BODIPY probes. This widely applicable labeling approach allowed us to follow fatty acid incorporation into lipid droplets based on the metabolic need of cells. When combined with quantitative SMLM, we further detected changes in enzyme densities on lipid droplets that are responsible for the incorporation or breakdown of fatty acids.