One of the most intriguing challenges in life sciences is to understand how a complex mixture of molecular particles and structures can make up a living cell. Despite the immense number of studies still much is unknown about the molecular basis of numerous biological processes such as cell proliferation, differentiation, intra- and extra-cellular communication and apoptosis. To increase our understanding about the complexity of these processes in living cells, experimental and especially quantitative data on the spatial-temporal organisation is required. Fluorescence based techniques are ideal tools for this type of studies.
Fluorescence Fluctuation Spectroscopy (FFS) is a family of fluorescence techniques that is capable of detecting concentration, dynamics and interactions of fluorescent particles down to the single-molecule level and, if desired, in the living cell. We are applying, optimising and expanding FFS techniques like FCCS, PCH, PIE-FLCS, stICS and RICS to describe signal transduction pathways, like the Galpha signalling pathway quantitatively. Thereto, the proteins of interest are genetically labeled with the various color- and lifetime variants of the green fluorescent protein (partly developed in our laboratory) expressed in living cells and studied by advanced fluorescence microscopes.