Regensburg 2002 – wissenschaftliches Programm
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SYBM: Physik biologischer Materie
SYBM 401: Physics of biological matter: Poster
SYBM 401.30: Poster
Dienstag, 12. März 2002, 18:00–19:30, H37
SINGLE-MOLECULE IMAGING OF LIPID-ANCHORED PROTEINS REVEALS DOMAINS IN THE CYTOPLASMIC LEAFLET OF THE CELL — •P. Lommerse1, G.A. Blab1, E. Snaar-Jagalska2, H.P. Spaink2 und T. Schmidt1 — 1Dept Biophysics, Leiden University — 2Dept Biology, Leiden University
A multitude of signal transduction cascades are initiated and mediated by interactions between proteins in or at the plasma membrane. The last decade evidence has accumulated that small subdomains located in the exoplasmic leaflet of the plasma membrane contain specific sets of proteins and in that way facilitate signal transduction cascades. However, it is not yet clear whether subdomains are also present in the cytoplasmic leaflet of the plasma membrane. To test this, a C-terminal fusion between enhanced Yellow Fluorescent Protein (eYFP) and the membrane targeting sequence of H-Ras was made. Lipid groups attached to cysteine residues in the H-Ras membrane targeting sequence anchor the fluorescent fusion protein to the cytoplasmic leaflet of the plasma membrane. Using single-molecule microscopy, the diffusion of individual membrane localized eYFP molecules was studied in live cells on the millisecond timescale. The results show that the diffusion of a fraction of molecules is constrained in domains with a size of 310 nm. This is the first time that such diffusional domains are observed in the cytoplasmic leaflet of the cell membrane. The measurement method described in this paper is suitable to further investigate the properties and biological relevance of the observed domains.