We previously showed that the association of CD4 and G_M3 ganglioside induced by CD4 ligand binding was required for the down-regulation of adhesion and that aggregation of ganglioside-enriched domains was accompanied by transient co-localization of LFA-1 (lymphocyte function-associated antigen-1), PI3K (phosphoinositide 3-kinase) and CD4. We also showed that these proteins co-localized with the G_M1 ganglioside that partially co-localized with G_M3 in these domains. In the present study, we show that CD4–p56^lck association in CD4 signalling is required for the redistribution of p56^lck, PI3K and LFA-1 in ganglioside-enriched domains, since ganglioside aggregation and recruitment of these proteins were not observed in a T-cell line (A201) expressing the mutant form of CD4 that does not bind p56^lck. In addition, we show that although these proteins associated in different ways with G_M1 and G_M3, all of the associations were dependent on CD4–p56^lck association. Gangliosides could associate with these proteins that differ in affinity binding and could be modified following CD4 signalling. Our results suggest that through these associations, gangliosides transiently sequestrate these proteins and consequently inhibit LFA-1-dependent adhesion. Furthermore, while structural diversity of gangliosides may allow association with distinct proteins, we show that the tyrosine phosphatase SHP-2 (Src homology 2 domain-containing protein tyrosine phosphatase 2), also required for the down-regulation of LFA-1-dependent adhesion, transiently and partially co-localized with PI3K and p56^lck in detergent-insoluble membranes without association with G_M1 or G_M3. We propose that CD4 ligation and binding with p56^lck and their interaction with G_M3 and/or G_M1 gangliosides induce recruitment of distinct proteins important for CD4 signalling to form a multimolecular signalling complex.