GPI-anchored proteins do not reside in ordered domains in the live cell plasma membrane

Nat Commun. 2015 Apr 21:6:6969. doi: 10.1038/ncomms7969.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CD59 Antigens / chemistry
  • CD59 Antigens / metabolism
  • Carcinoma / metabolism
  • Cell Line, Tumor
  • Cell Membrane / metabolism*
  • Glycosylphosphatidylinositols / chemistry
  • Glycosylphosphatidylinositols / metabolism*
  • Green Fluorescent Proteins
  • Humans
  • Immunoglobulin Fab Fragments
  • Lipid-Linked Proteins / chemistry
  • Lipid-Linked Proteins / metabolism*
  • Protein Structure, Tertiary

Substances

  • CD59 Antigens
  • Glycosylphosphatidylinositols
  • Immunoglobulin Fab Fragments
  • Lipid-Linked Proteins
  • Green Fluorescent Proteins