Skip to content
Login Register

#membrane microdomains

3 public questions tagged with this topic.

Plasma Membrane

Which of the following statements about lipid rafts is correct?

Lipid rafts are defined as transient, nanoscale domains 10-200 nm enriched in saturated sphingolipids including sphingomyelin and glycosphingolipids, cholesterol, and GPI-anchored proteins plus acylated inner leaflet proteins like Src kinases, exhibiting liquid-ordered phase where acyl chains are extended and ordered yet laterally mobile, surrounded by liquid-disordered PC-rich matrix. Their cholesterol dependence arises from hydrogen bonding between cholesterol hydroxyl and sphingolipid amide, plus van der Waals interaction with saturated chains, increasing order and thickness. Importantly ra

Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 10: Lipid Rafts and Membrane Domains.

View Details
Glycolipid and Phospholipid

Which of the following is NOT abundant in lipid rafts?

Isolation detergent resistant membranes quantitative shotgun lipidomics show selective lipid sorting excluding certain anionic glycerophospholipids and enriching sphingolipid cholesterol species. Sphingomyelin cholesterol ceramide cerebrosides galactosylceramide gangliosides GM1 associate preferentially due saturated acyl chains fourteen to twenty four carbons hydrogen bonding amide hydroxyl enabling tight packing into liquid ordered phase high chain order low fluidity lateral diffusion moderate. Glycolipids project bulky headgroups outward stabilizing raft extracellular leaflet sterically hin

Ref: Levental I et al., PNAS 2010, Lipid raft composition PS depleted not enriched and coupling.

View Details
Glycolipid and Phospholipid

Which feature allows lipid rafts to regulate signal transduction?

Signal compartmentalization arises because cholesterol sphingolipid rich liquid ordered platforms concentrate specific proteins while excluding others lowering activation threshold facilitating downstream signaling. Cholesterol fills interstitial gaps between sphingomyelin saturated chains raising order parameter decreasing fluidity variance thickening bilayer promoting sequestration GPI anchored proteins dual acylated Src family kinases Fyn Lyn palmitoylated LAT adaptor PAG and flotillins. Extracellular ganglioside glycans form lattice galectins stabilizing clusters via multivalent interactio

Ref: Simons & Toomre, Nature Rev Mol Cell Biol 2000, Raft signaling dependence cholesterol sphingolipids and kinases.

View Details