Effects of cholesterol depletion by cyclodextrin on the sphingolipid microdomains of the plasma membrane

Autor: Subburaj Ilangumaran, Daniel C. Hoessli
Rok vydání: 1998
Předmět:
Liquid ordered phase
Glycosylphosphatidylinositols
Caveolin 1
Beta-Cyclodextrins
ddc:616.07
Biochemistry
Cell membrane
Mice
Caveolin
Lymphocytes
beta-Cyclodextrins
Protein-Tyrosine Kinases
Transmembrane protein
Cell biology
Endothelium
Vascular/cytology/drug effects
Membrane
medicine.anatomical_structure
Cholesterol
Hyaluronan Receptors
Detergents/pharmacology
Antigens
CD59/metabolism
lipids (amino acids
peptides
and proteins)
Cholesterol/ metabolism
Research Article
Detergents
CD59 Antigens
G(M1) Ganglioside
Biology
Caveolins
Sphingolipids/chemistry/ metabolism
medicine
Animals
Humans
Antigens
CD44/metabolism
Molecular Biology
Cyclodextrins
Sphingolipids
Antigens
Thy-1/metabolism
Cell Membrane
Membrane Proteins
Membrane Proteins/chemistry/drug effects/metabolism
Cell Biology
Cyclodextrins/metabolism/ pharmacology
Lymphocytes/chemistry/drug effects/metabolism
Sphingolipid
Glycosylphosphatidylinositols/metabolism
Protein-Tyrosine Kinases/drug effects/metabolism
carbohydrates (lipids)
Membrane protein
Cell Membrane/chemistry/drug effects/ metabolism
Antigens
CD45/metabolism
Leukocyte Common Antigens
Thy-1 Antigens
Endothelium
Vascular
G(M1) Ganglioside/metabolism
Zdroj: Biochemical Journal, Vol. 335, No Pt 2 (1998) pp. 433-440
ISSN: 0264-6021
Popis: Sphingolipid microdomains are thought to result from the organization of plasma membrane sphingolipids and cholesterol into a liquid ordered phase, wherein the glycosylphosphatidylinositol (GPI)-anchored proteins are enriched. These domains, resistant to extraction by cold Triton X-100, can be isolated as buoyant membrane complexes (detergent-resistant membranes) in isopycnic density gradients. Here the effects of methyl-β-cyclodextrin (MBCD), a specific cholesterol-binding agent that neither binds nor inserts into the plasma membrane, were investigated on the sphingolipid microdomains of lymphocytes. MBCD released substantial quantities of GPI-anchored Thy-1 and glycosphingolipid GM1, and also other surface proteins including CD45, and intracellular Lck and Fyn kinases. From endothelial cells, MBCD released GPI-anchored CD59, and CD44, but only a negligible amount of caveolin. Most MBCD-released Thy-1 and CD59 were not sedimentable and thus differed from Thy-1 released by membrane-active cholesterol-binding agents such as saponin and streptolysin O, or Triton X-100. Unlike that released by Triton X-100, only part of the Thy-1 molecules released by MBCD was buoyant in density gradients and co-isolated with GM1. Finally, treatment of Triton X-100-isolated detergent-resistant membranes with MBCD extracted most of the cholesterol without affecting the buoyant properties of Thy-1 or GM1. We suggest that (1) MBCD preferentially extracts cholesterol from outside, rather than within the sphingolipid microdomains and (2) this partly solubilizes GPI-anchored and transmembrane proteins from the glycerophospholipid-rich membrane and releases sphingolipid microdomains in both vesicular and non-vesicular form.
Databáze: OpenAIRE
Externí odkaz: