Publications in Scientific Journals:

S. Sunzenauer, V. Zojer, M. Brameshuber, A. Tröls, J. Weghuber, H. Stockinger, G. Schütz:
"Determination of Binding Curves via Protein Micropatterning In Vitro and in Living Cells";
Cytometry Part A, 83 (2013), 847 - 854.

English abstract:
Quantification of protein interactions in living cells is of key relevance for understanding
cellular signaling. With current techniques, however, it is difficult to determine binding
affinities and stoichiometries of protein complexes in the plasma membrane. We introduce
here protein micropatterning as a convenient and versatile method for such investigations.
Cells are grown on surfaces containing micropatterns of capture antibody to a
bait protein, so that the bait gets rearranged in the live cell plasma membrane. Upon
interaction with the bait, the fluorescent prey follows the micropatterns, which can be
readout with fluorescence microscopy. In this study, we addressed the interaction between
Lck and CD4, two central proteins in early T-cell signaling. Binding curves were recorded
using the natural fluctuations in the Lck expression levels. Surprisingly, the binding was
not saturable up to the highest Lck expression levels: on average, a single CD4 molecule
recruited more than nine Lck molecules. We discuss the data in view of protein- and
lipid-mediated interactions.

Micropatterning; plasma membrane; CD4; Lck; single molecule microscopy; equilibrium binding constant

Created from the Publication Database of the Vienna University of Technology.