Also called membrane rafts or lipid rafts, they are specific membrane sites, rich in cholesterol and sphingolipids.

These fractions typically contain caveolae and 'membrane rafts' thought to be enriched in active signaling complexes [ 34 35 43 ] .

Crosslinking Thy-1 molecules in the membrane raft, in the context of strong costimulatory signaling through CD28 in mouse T cells can act to some extent as a substitute activating signal for T-cell receptor signaling.