Figure 5.

p56^Lck triggers CD4 segregation in DRMs. DRMs were prepared from CEM and HL60 cells as described in Materials and Methods and fractions were analyzed by SDS/PAGE and Western blotting. (A) Typical distribution of CD4, p56^Lck, CD71, and AlkP is shown. Data are representative of three independent experiments. (B) Disruption of the CD4-p56^Lck complex by 1,10-O-phenanthroline redistributes CD4, but not p56^Lck, out of DRMs. CEM cells were treated for 30 min at 37°C with 1,10-O-phenanthroline before starting the fractionation procedure, and distribution of CD4 and p56^Lck was analyzed. Data are representative of three independent experiments. (C) CD4 is palmitoylated in both CEM and HL60 cells. Cells were metabolically labeled with [³H]palmitate, and CD4 palmitoylation was revealed as described in Materials and Methods. Data are representative of three independent experiments.