Fig. 4

Immunoprecipitation of ln-5 from cultured 70N normal and MDA-MB-435 tumor cells. Cells were metabolically labeled, then cell monolayer (Cells) or spent medium (Medium) samples of equal volume and protein concentration were immunoprecipitated using α3-specific, β3-specific or no antibody, as indicated. Immunoprecipitations were performed prior to disruption of ln-5 heterotrimers. Following precipitation, proteins were reduced, denatured, and electrophoresed on 5% acrylamide SDS gels. The ln-5 chains are indicated by arrows. Arrows indicate unprocessed forms and lines, processed forms. Positions of size standards are indicated at right.