N-terminal protein acylation confers localization to cholesterol, sphingolipid-enriched membranes but not to lipid rafts/caveolae

Mol Biol Cell. 2001 Nov;12(11):3601-17. doi: 10.1091/mbc.12.11.3601.

Abstract

When variably fatty acylated N-terminal amino acid sequences were appended to a green fluorescent reporter protein (GFP), chimeric GFPs were localized to different membranes in a fatty acylation-dependent manner. To explore the mechanism of localization, the properties of acceptor membranes and their interaction with acylated chimeric GFPs were analyzed in COS-7 cells. Myristoylated GFPs containing a palmitoylated or polybasic region colocalized with cholesterol and ganglioside GM(1), but not with caveolin, at the plasma membrane and endosomes. A dipalmitoylated GFP chimera colocalized with cholesterol and GM(1) at the plasma membrane and with caveolin in the Golgi region. Acylated GFP chimeras did not cofractionate with low-density caveolin-rich lipid rafts prepared with Triton X-100 or detergent-free methods. All GFP chimeras, but not full-length p62(c-yes) and caveolin, were readily solubilized from membranes with various detergents. These data suggest that, although N-terminal acylation can bring GFP to cholesterol and sphingolipid-enriched membranes, protein-protein interactions are required to localize a given protein to detergent-resistant membranes or caveolin-rich membranes. In addition to restricting acceptor membrane localization, N-terminal fatty acylation could represent an efficient means to enrich the concentration of signaling proteins in the vicinity of detergent-resistant membranes and facilitate protein-protein interactions mediating transfer to a detergent-resistant lipid raft core.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acylation*
  • Animals
  • Biomarkers
  • COS Cells
  • Caveolae / metabolism*
  • Caveolin 1
  • Caveolins / metabolism
  • Cell Fractionation
  • Cell Membrane / metabolism
  • Chlorocebus aethiops
  • Cholesterol / metabolism*
  • Detergents
  • Filipin / metabolism
  • G(M1) Ganglioside / metabolism
  • Green Fluorescent Proteins
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Membrane Microdomains / metabolism*
  • Membrane Proteins / metabolism
  • Octoxynol
  • Organelles
  • Proteins / metabolism*
  • Proto-Oncogene Proteins / metabolism
  • Proto-Oncogene Proteins c-yes
  • Solubility
  • Sphingolipids / metabolism*
  • Transferrin / metabolism
  • Vesicular Transport Proteins
  • Xanthenes
  • src-Family Kinases*

Substances

  • Biomarkers
  • Caveolin 1
  • Caveolins
  • Detergents
  • Luminescent Proteins
  • Membrane Proteins
  • Proteins
  • Proto-Oncogene Proteins
  • Sphingolipids
  • Transferrin
  • Vesicular Transport Proteins
  • Xanthenes
  • early endosome antigen 1
  • Green Fluorescent Proteins
  • G(M1) Ganglioside
  • Texas red
  • Filipin
  • Octoxynol
  • Cholesterol
  • Proto-Oncogene Proteins c-yes
  • src-Family Kinases