Photoactivatable fluorescence has enabled several imaging methods that provide information-rich, quantitative data for dissecting biological structure and dynamics. These include fluorescence pulse-chase imaging as well as super-resolution imaging approaches like photoactivated localization microscopy (PALM). Three vignettes demonstrate insights these tools provide into the cytoskeleton, viruses, and the endoplasmic reticulum.

Using pulse-chase imaging approaches, we demonstrate that the lamellipodial actin network at the edge of cells evolves into the lamella behind it. This occurs during edge retraction, when myosin II redistributes to the lamellipodial actin and condenses it into an actin arc.

Imaging with minimal perturbations is crucial to gain meaningful insights into processes such as the assembly of the HIV-1 Gag protein into virus-like particles (VLPs). The impact of the fluorescent label on VLP assembly is controversial due to their size, which are too small to resolve using diffraction-limited imaging. We address this by studying the morphology of VLPs with PALM imaging.

The endoplasmic reticulum is a complex structure composed of membrane sheets and tubules. We use a combination of 3D and live cell PALM to dissect the organization of reticulons, proteins responsible for shaping the ER.


Wednesday, April 20, 2011, 11:45. Seminar Room

Hosted by Prof. Melike Lakadamyali