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E. Sevcsik, M. Brameshuber, M. Fölser, J. Weghuber, A. Honigmann:
"GPI-anchored proteins do not reside in ordered domains in the live cell plasma membrane";
Nature Communications, 6 (2015), 69691 - 696910.

The organization of proteins and lipids in the plasma membrane has been the subject of a
long-lasting debate. Membrane rafts of higher lipid chain order were proposed to mediate
protein interactions, but have thus far not been directly observed. Here we use protein
micropatterning combined with single-molecule tracking to put current models to the test: we
rearranged lipid-anchored raft proteins (glycosylphosphatidylinositol(GPI)-anchored-mGFP)
directly in the live cell plasma membrane and measured the effect on the local membrane
environment. Intriguingly, this treatment does neither nucleate the formation of an ordered
membrane phase nor result in any enrichment of nanoscopic-ordered domains within the
micropatterned regions. In contrast, we find that immobilized mGFP-GPIs behave as
inert obstacles to the diffusion of other membrane constituents without influencing their
membrane environment over distances beyond their physical size. Our results indicate that
phase partitioning is not a fundamental element of protein organization in the plasma
membrane.