The platelet receptor for type III collagen (TIIICBP) is present in platelet membrane lipid microdomains (rafts).
Platelet interactions with collagen are orchestrated by the presence or the migration of platelet receptor(s) for collagen into lipid rafts, which are specialized lipid microdomains from the platelet plasma membrane enriched in signalling proteins. Electron microscopy shows that in resting platelets, TIIICBP, a receptor specific for type III collagen, is present on the platelet membrane and associated with the open canalicular system, and redistributes to the platelet membrane upon platelet activation. After platelet lysis by 1% Triton X-100 and the separation of lipid rafts on a discontinuous sucrose gradient, TIIICBP is recovered in lipid raft-containing fractions and Triton X-100 insoluble fractions enriched in cytoskeleton proteins. Platelet aggregation, induced by type III collagen, was inhibited after disruption of the lipid rafts by cholesterol depletion, whereas platelet adhesion under static conditions did not require lipid raft integrity. These results indicate that TIIICBP, a platelet receptor involved in platelet interaction with type III collagen, is localized within platelet lipid rafts where it could interact with other platelet receptors for collagen (GP VI and alpha2beta1 integrin) for efficient platelet activation.
Maurice
Pascal
P
INSERM, U 553, IFR 105, Institut d'Hématologie, Université Paris VII Denis Diderot, 75475, Paris, France.
Waeckel
Ludovic
L
Pires
Viviane
V
Sonnet
Pascal
P
Lemesle
Monique
M
Arbeille
Brigitte
B
Vassy
Jany
J
Rochette
Jacques
J
Legrand
Chantal
C
Fauvel-Lafève
Françoise
F
D001792:Blood Platelets / Q000378:metabolism* / Q000648:ultrastructure; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D002784:Cholesterol / Q000378:metabolism; D024061:Collagen Type III / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D038982:Integrin alpha2beta1 / Q000378:metabolism; D021962:Membrane Microdomains / Q000378:metabolism* / Q000648:ultrastructure; D010446:Peptide Fragments / Q000378:metabolism; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism; D038981:Receptors, Collagen / Q000378:metabolism*
D024061:Collagen Type III; D038982:Integrin alpha2beta1; D010446:Peptide Fragments; D010980:Platelet Membrane Glycoproteins; D038981:Receptors, Collagen; C098341:platelet membrane glycoprotein VI; C519344:platelet receptor for type III collagen, human; C082835:thrombin receptor peptide (42-47); D002784:Cholesterol