GPI-microdomains (membrane rafts) and signaling of the multi-chain interleukin-2 receptor in human lymphoma/leukemia T cell lines

摘要: Subunits (α, β and γ) of the interleukin-2 receptor complex (IL-2R) are involved in both proliferative activation-induced cell death (AICD) signaling T cells. In addition, γ chains shared by other cytokines (e.g. IL-7, IL-9, IL-15). However, molecular mechanisms responsible for recruiting/sorting α to at surface not clear. Here we show, four lines human adult T cell lymphoma/leukemia origin, that three IL-2R subunits compartmented together with HLA glycoproteins CD48 molecules plasma membrane, means fluorescence resonance energy transfer (FRET), confocal microscopy immuno-biochemical techniques. addition γc constitutively expressed detergent-resistant membrane fractions (DRMs) T cells, IL-2Rα (CD25) was also found DRMs, independently its ligand-occupation. Association CD25 rafts confirmed colocalization GM-1 ganglioside. Depletion cholesterol using methyl-β-cyclodextrin substantially reduced co-clustering HLA-DR, as well IL-2 stimulated tyrosine-phosphorylation STATs (signal transducer activator transcription). These data indicate a GPI-microdomain (raft)-assisted recruitment vicinity chains. Rafts may promote rapid formation high affinity complex, even low levels stimulus, form platform regulation induced signals GPI-proteins CD48). Based on these data, integrity GPI-microdomains seems critical signal transduction through complex.