Biophysical Imaging

Peroxisomes are small (100-300 nm) intracellular organelles that fulfil many anabolic and catabolic functions. Mistargeting of peroxisomal proteins, which are imported from the cytosol, therefore leads to severe diseases making this organelle an object of research of utmost importance for medical applications. The import of proteins is mediated in a by now unknown manner through a transient translocation pore which assembles either in a way similar to pore forming toxins or through a liquid/liquid phase separated matrix. We here aim at adding knowledge about peroxisomes using a toolbox of advanced (super-resolution) microscopy methods. We use STED and Minflux super-resolution microscopy and spectroscopy to study the distribution of peroxisomal proteins involved in protein translocation on the peroxisomal membrane as well as we studied the diffusion dynamics of the peroxisomal import receptor and its cargo proteins in the cytosol of cells. Further, we employ a photoactivatable protein to induce and quantify peroxisomal import as well as we study peroxisomal movements in living cells through fast timelapse imaging and sophisticated image analysis.