Regensburg 2004 – scientific programme

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SYLS: Life Sciences on the Nanometer Scale - Physics Meets Biology

SYLS 1: Symposium "Life Sciences on the Nanometer Scale - Physics Meets Biology"

SYLS 1.2: Invited Talk

Wednesday, March 10, 2004, 14:30–15:00, H 37

Single-Molecule Cellular Signaling — •Thomas Schmidt — Physics of Life Processes, Leiden Institute of Physics, Leiden University

Recent studies showed that several types of membrane microdomains are involved in H-Ras signal transduction. However, our knowledge about the in vivo dynamics of these domains is still in its infancy. In this study, the effect of plasma membrane organization on the activation of the small GTPase H-Ras was studied by single-molecule fluorescence microscopy. Diffusion analysis revealed a major, fast diffusing population and a minor, slow diffusion population for both inactive and active H-Ras. Activation of H-Ras resulted in a transfer from free diffusion to confinement into 200 nm-sized domains for the minor, slowly diffusing fraction. This is a first indication for the relevance of membrane ultrastructure on cellular signalling.