Fig. 2. Immunoprecipitation analysis of solubilized lysosomal membranes. Cytosolic proteins (15 µg) from fibroblasts deprived of serum for 18 hours were separated by SDS-PAGE and immunoblotted with the indicated antibodies. Solubilized lysosomal membrane proteins (100 µg) from fibroblasts deprived of serum for 18 hours were immunoprecipitated with anti-Hsc70, anti-Hip and anti-p19 as a negative control. Samples were treated as described in Materials and Methods. Blots were probed with specific antibodies against the indicated proteins and developed with chemiluminescense (see Materials and Methods).