We have investigated raft formation in @entity1 platelets in response to cell activation. Lipid phase separation and domain formation were detected using the fluorescent dye @entity9717 ( @entity9717 ) that preferentially partitions into gel-like lipid domains. We showed that when @entity1 platelets are activated by cold and physiological agonists, rafts coalesce into visible aggregates. These events were disrupted by depletion of membrane @entity165 . Using Fourier transform infrared spectroscopy (FTIR), we measured a thermal phase transition at around 30 degrees C in intact platelets, which we have assigned as the liquid-ordered to the liquid-disordered phase transition of rafts. Phase separation of the phospholipid and the @entity4291 -enriched rafts could be observed as two phase transitions at around 15 and 30 degrees C, respectively. The higher transition, assigned to the rafts, was greatly enhanced with removal of membrane @entity165 . Detergent-resistant membranes (DRMs) were enriched in @entity165 (50%) and @entity4291 (20%). The multi-functional platelet receptor @entity4210 selectively partitioned into DRMs, whereas the GPI-linked protein @entity9819 and the major platelet integrin alpha(IIb)beta(3a) did not, which suggests that the clustering of proteins within rafts is a regulated process dependent on specific lipid protein interactions. We suggest that raft aggregation is a dynamic, reversible physiological event triggered by cell activation.

Evidence for a physiological role for membrane rafts in XXXX platelets.

@entity1 :: ('9606', 'Species') :: ['human'] @entity4210 :: ('948', 'Gene') :: ['CD36'] @entity165 :: ('MESH:D002784', 'Chemical') :: ['cholesterol'] @entity9819 :: ('1604', 'Gene') :: ['CD55'] @entity4291 :: ('CHEBI:17636', 'Chemical') :: ['sphingomyelin'] @entity9717 :: ('MESH:C024286', 'Chemical') :: ["1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine perchlorate", 'diI-C(18)']
@entity1 :: (9606,Species) :: ['human']
