Prof. Dr. Alexander Rohrbach (CIBSS-AI), IMTEK (Technical Faculty), University of Freiburg
In this project we investigate how bacterial lectins drive the dynamics of host cell cortical cytoskeleton for bacterial invasion. The binding of lectin LecA may induce membrane domains (enriched in saturated Gb3 and the GPI-anchored protein CD59) at the outer leaflet, followed by membrane curvature formation through acto-myosin required for endocytic uptake (see sketch in the figure). In collaboration with the group of W. Römer we inspect the driving mechanisms of both LecA cluster formation and opposite dynamics of septins and actin?
Cell cortex observations from milliseconds to hours requires new optical technology such as Rotating Coherent Scattering (ROCS) microscopy, which offers 160nm spatial resolution at > 100 Hz and without fluorescence labeling.
In this project we will extend the ROCS technology to life cell imaging at several focal planes using several lasers and fast cameras. A novel multi-phase brightfield mode combined with deep learning algorithms (in collaboration with the group of T. Brox) will enable ROCS imaging with sensitivity and specificity, which will be combined with fluorescence microscopy in addition (see first images in figure).
We expect to discover new insights about the reorganization of the actin and septin cortex during and after endocytosis on so far unreached spatial and temporal scales.