Figure 1

Sca associates with Dl. A-C. Fluorescent photomicrographs of different cell lines treated with Sca-GFP medium for 30 minutes. Cells simultaneously fixed and rinsed in 4% paraformaldehyde/1X PBS are shown in the insets. Experiments were repeated three times. D. Western blots showing recovery of Dl in Sca immuno-precipitates from total protein extracts prepared from S2-Dl cells treated with S2-Sca cells. S2-Sca cells were used instead of Sca conditioned medium to maximize the ratio of bound to unbound Sca. Cross-linker = membrane insoluble and cleavable 3,3'- Dithiobis (sulfosuccinimidylpropionate) (DTSSP), which cross-links proteins interacting at the cell surface. IP Ab = antibody used for immunoprecipitation; W Ab = antibody used on the western blot; ppt = immunoprecipitate; super = supernatant. Experiments were repeated two times.