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SYBP: Biophotonik

SYBP 4: Postersitzung

SYBP 4.3: Poster

Donnerstag, 7. März 2002, 17:45–20:00, Schloss

Determination of the mobility of membrane proteins in living cells with Fluorescence Correlation Spectroscopy — •Margarita Khazarchyan¹, Jan Exmann¹, Elmar Thews¹, Uwe Gerken¹, Andrea Melzer¹, Jörg Wrachtrup¹, and Reiner Eckert² — ¹3. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart — ²Biologisches Institut Abt. Biophysik, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart

Fluorescence correlation spectroscopy (FCS) is an attractive method of measuring diffusion processes in living cells. We use one- and two-photon excitation for investigation of translational mobility in the cytoplasm and on plasma membranes using different fluorophores for intracellular applications of FCS. Here we show an application of this approach to study the mobility of the TRAF2-protein in cytoplasm of cells. Diffusion coefficients of the TRAF2-protein were determined and we can show that the coefficient depends on the location of the TRAF2-protein in the cytoplasm: when it is close to the membrane the diffusion coefficient is remarkably slower than within the cytoplasm.

We also want to show an application of FCS to study gap junction intercellular membrane channels. Gap junction channels provide direct cell-cell communication. We tagged the protein subunits of gap junctions with an autofluorescent reporter green fluorescent protein (GFP) to examine the dynamics of gap junction hemichannels in the plasma membrane of living cells. Both single molecule results are in good agreement with predictions based on structural data.