Regensburg 2013 – scientific programme

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BP: Fachverband Biologische Physik

BP 28: Focus session: Intracellular Spectroscopy

BP 28.2: Talk

Thursday, March 14, 2013, 10:00–10:15, H44

Quantifying the milieu of organelles in living cells via fluorescence lifetime imaging — Nisha Pawar, Saeedeh Aliaskarisohi, and •Matthias Weiss — Experimental Physics I, University of Bayreuth, Germany

Compartmentalization is a hallmark of eukaryotic cells. A diverse set of organelles is dynamically maintained by eukaryotes to provide biochemical reaction vessels with a distinct milieu. Prominent examples are the endoplasmic reticulum (ER) and the Golgi apparatus, both of which are major constituents of the cell's secretory pathway. Along this pathway, about 10,000 different protein species are sorted and eventually sent to their final destination. It has long been hypothesized that the lumenal milieu of the ER and the distinct cisternae of the Golgi apparatus provide important cues for these sorting processes, yet assessing their milieu in a living cell has been a challenge. Using fluorescence lifetime imaging (FLIM), we have monitored the milieu of the Golgi apparatus and the ER under various conditions. We find a significant change in the Golgi milieu towards that of the ER when adding perturbative drugs. Moreover, following the trajectory of proteins from the ER through the Golgi, we can attribute distinct milieus to the individual sub-compartments along the secretory pathway, e.g. Golgi cisternae.