Both raft- and non-raft proteins associate with CHAPS-insoluble complexes: Some APP in large complexes

Alexander Rouvinski, Inbar Gahali-Sass, Ilana Stav, Esther Metzer, Henri Atlan, Albert Taraboulos*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Components of caveolae and lipid rafts are characterized by their buoyancy after detergent extraction. Using flotations in density gradients, we now show that non-raft membrane molecules are also associated with detergent-insoluble, buoyant assemblies. When Triton X-100 cellular extracts were spun to equilibrium in Nycodenz, only components of classical rafts floated. In contrast, with the zwitterionic detergent CHAPS, non-raft residents such as calnexin and APP also buoyed. When CHAPS extracts were spun in non-equilibrium (velocity) conditions, some raft components rapidly exited the input fractions while other raft markers and non-raft molecules remained relatively immobile. This pointed to size heterogeneities of CHAPS-insoluble complexes. Combined velocity/equilibrium gradients broadly divided CHAPS-insoluble membrane complexes into three size categories, which all contained cholesterol and the glycosphingolipid GM1. Large complexes were enriched in caveolin and ESA. Medium size complexes were enriched in PrP, whereas small complexes contained non-raft proteins, PrP, and some ESA. While Alzheimer's APP was primarily confined to small assemblies, a portion of its glycosylated form did buoy with large complexes. Large CHAPS-insoluble complexes resemble, but are not equal to, classical rafts. These findings extend considerably the range of detergent-insoluble membranal domains.

Original languageAmerican English
Pages (from-to)750-758
Number of pages9
JournalBiochemical and Biophysical Research Communications
Issue number4
StatePublished - 5 Sep 2003

Bibliographical note

Funding Information:
This work was supported by the Israel Center for the Study of Emerging Diseases. We thank Avihai Hovav and Yuval Tal for help with the animal tissues.


  • Alzheimer
  • Cholesterol
  • Detergent
  • GM1
  • GPI
  • Insoluble
  • Microdomain


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