Berlin 2005 – wissenschaftliches Programm
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AKB: Biologische Physik
AKB 100: Poster Session I
AKB 100.54: Poster
Samstag, 5. März 2005, 16:45–18:45, Poster TU D
Investigation of the TNF Mediated Apaptotic Pathway by Means of Fluorescence Correlation Spectroscopy — •Carsten Tietz1, Margarita Gerken1, Elmar Thews1, Anja Krippner-Heidenreich2, Peter Scheurich2, and Jörg Wrachtrup1 — 1Institute of Physics, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart — 2Institute of Cell Biology and Immunology, University of Stuttgart, Allmandring 31, 70569 Stuttgart
We investigate the behavior of apoptosis mediating cell receptors (TNF-R1/2) before and after stimulation by means of FCS. Studies on TNF-R show that the response of the cell on stimulation with TNF is a slowing down of the diffusion by approximately one order of magnitude but only a very slight increase of the intensity per diffusing particle. Several experiments were carried out to reveal the origin of this slowing down. We can exclude aggregation of receptors, interaction of the cytoplasmic domain of the receptor with the cytoskeleton, and change of the viscosity of the whole plasma membrane. On the other hand, cholesterol depletion of the membrane with MβCD show no effect on the diffusion coefficient of activated TNF-R2 but TNF-R1 shows an increases of the diffusion coefficient after MβCD treatment. From this results we conclude that TNF-receptors can be associated with membrane micro domains. Whereas TNF-R1 can be associated with cholesterol rich domains, the TNF-R2 must be associated to a so far unknown type of domain.