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G. Fülöp, M. Brameshuber, A. Arnold, G. Schütz, E. Sevcsik:
"Determination of the Membrane Environment of CD59 in Living Cells";
Biomolecules, 8 (2018), 2801 - 2813.

The organization and dynamics of proteins and lipids in the plasma membrane, and
their role in membrane functionality, have been subject of a long-lasting debate. Specifically, it is
unclear to what extent membrane proteins are affected by their immediate lipid environment and
vice versa. Studies on model membranes and plasma membrane vesicles indicated preferences
of proteins for lipid phases characterized by different acyl chain order; however, whether such
phases do indeed exist in live cells is still not known. Here, we refine a previously developed
micropatterning approach combined with single molecule tracking to quantify the influence of the
glycosylphosphatidylinositol-anchored (GPI-anchored) protein CD59 on its molecular environment
directly in the live cell plasma membrane. We find that locally enriched and immobilized CD59
presents obstacles to the diffusion of fluorescently labeled lipids with a different phase-partitioning
behavior independent of cell cholesterol levels and type of lipid. Our results give no evidence for
either specific binding of the lipids to CD59 or the existence of nanoscopic ordered membrane regions
associated with CD59.

plasma membrane; CD59; lipid; diffusion; micropatterning; GPI-anchored protein; membrane rafts