Cell fractionation studies of IL-4–treated monocytes at various calcium concentrations. Cell preparation, sample work-up, and immunoblotting are described in Materials and Methods. Cell lysis was performed at two calcium concentrations (10−6 mol/L for A through D and 5 × 10−8 mol/L for E through H). After lysis, the membranes were spun down at 100,000g. The membrane pellet and the supernatant of the 100,000g centrifugation, which was considered the cytosol, were prepared for electrophoresis as described in the Materials and Methods section. (A) Membrane pellet; (B) cytosol; (C) washing supernatant (washed at 10−6mol/L calcium); (D) washed membrane pellet (washed at 10−6 mol/L calcium); (E) membrane pellet; (F) cytosol; (G) washing supernatant (washed at 5 × 10−8 mol/L calcium); (H) washed membrane pellet (washed at 5 × 10−8 mol/L calcium).
