Aggregation of Lipid Rafts Accompanies Signaling via the T Cell Antigen Receptor

摘要: The role of lipid rafts in T cell antigen receptor (TCR) signaling was investigated using fluorescence microscopy. Lipid labeled with cholera toxin B subunit (CT-B) and cross-linked into patches displayed characteristics isolated biochemically, including detergent resistance colocalization raft-associated proteins. LCK, LAT, the TCR all colocalized patches, although association sensitive to nonionic detergent. Aggregation by anti-CD3 mAb cross-linking also caused coaggregation However, protein tyrosine phosphatase CD45 did not colocalize either CT-B or CD3 patches. Cross-linking strongly induced phosphorylation recruitment a ZAP-70(SH2)2–green fluorescent (GFP) fusion Also, patching events analagous stimulation, same dependence on expression key molecules. Targeting LCK necessary for these events, as nonraft- associated transmembrane chimera, which could reconstitute CT-B–induced signaling. Thus, our results indicate mechanism whereby engagement promotes aggregation rafts, facilitates whilst excluding CD45, thereby triggering phosphorylation.