Fig. 4.
Immunocomplexes between cdk4 and cyclin D2 were detected only in the presence of anti–TGF-β antibody.
After starvation in methionine-free DMEM for 4 hours, CD34+progenitors were metabolically labeled for 18 hours with35S-methionine/cysteine in the presence or absence of soluble TGF-β1 or anti–TGF-β antibody. Cell lysates were first immunoprecipitated with agarose-coated polyclonal CDK4 antibody. Subsequent serial immunoprecipitation was then carried out further using agarose-coated polyclonal cyclin D2 antibody. Samples were run on a 10% SDS-PAGE gel, dried, and exposed to autoradiogram film.