Lipid Raft

Lipid Raft

1. Fonctions

   • Transduction of signal
     • Rcp + L
       • Recruitment of proteins
   • Endocytosis (of receptors)
     • CD44 + LR
       • Ac. hyaluronic
         • Internalisation (via Calveolin)
           • Lysosome
             • RCP degrated
   • Cellular polarisation
     • Apical MB : GPI proteins
     • Basal MB : MB proteins
   • Viral budding
     • Hemagglutin

2. Structure

   • 35-40% in plasma MB
   • Outer layer
   • Cytosolic face
     • Calveolin
       • Stabilisation of LR

3. Composition

   • Cholesterol
     • +++
     • MB rigidity
   • Glycoshingolipids
     • Shyngosine
     • Outer leaflet of the lipid bilayer
     • When @ cell surface
       • Intercellular communication
       • Important role in cell adhesion mecanisms
     • When associated with LR
       • Signal transduction
       • Receptor for pathogens
       • Addressing proteins
   • Proteins
     • GPI-anchored proteins
       • Associated to the MB
       • Biosynthesis of GPI-proteins
         • PICTURE
     • MB proteins
       • Extracellular domain
         • EGF receptor
         • Area rich in cystein
       • Transmembrane domain
         • Ex : for virus enveloppe
           • Hemagglutin
             • HA1 : attachement viral particule
             • HA2 : release of the virus' contents
       • Intracellular Domain
       • For LR adressing

4. Microdomaine formation via linking between

   • Cholesterol
   • Glycosphingolipids

5. Detergent insoluble